Science Grade 10 Part 3

DEPED COPYSummary • The nervous system is composed of cells, tissues, and organs that regulate the body’s responses to internal and external stimuli. Each component of the nervous system has a specific role to do as an important part of a team. • The nervous system has two main divisions, which are the Central Nervous System (CNS) and the Peripheral Nervous System (PNS). • The Central Nervous System (CNS) serves as the main “processing center” for the entire nervous system. It has two main components, which are the brain, and the spinal cord. • The Peripheral Nervous System (PNS) contains all nerves that extend outside the brain and spinal cord. It has two main divisions, which are the Somatic Nervous System and the Autonomic Nervous System. • The basic unit of the nervous system is the nerve cell, called neuron. Neurons have dendrites and axons that aid in transmitting the message. • Neurons have the special ability to carry signals or impulses. A nerve impulse is an electrochemical gradient moving along a neuron. The space between neurons is called synapse. A stimulus is any factor in the environment that may induce a nerve impulse that initiates physiological and behavioural changes. A response is a reaction to a condition or stimulus. To survive, an organism must be able to respond to a stimulus. Reaction time is the length of time between application of a stimulus and detection of a response. • When a receptor such as an organ perceives a stimulus, the impulse is sent to the brain by the sensory neurons, transmitting information from one nerve cell to another. As the message reaches the brain, it processes the information and commands an effector such as a muscle or an organ to respond. The message coming from the brain is sent through the motor neurons. • The Endocrine System consists of glands that secrete chemicals called hormones which control various body processes. This control system usually brings about slow changes in the body because chemical agents move more slowly than nerve impulses. The major glands in the body are the pituitary, thyroid, parathyroid, thymus, adrenal, pancreas, ovaries and testes. 185 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

DEPED COPY• Hormones affect various processes in the body as they regulate and balance the functioning of organs, tissues, and cells. Hormones greatly influence growth, appearance, emotions, and reproductive functions. It plays an essential role in the prevalence of disorders such as diabetes, thyroid disease, growth and/or sexual dysfunction. Hormones act in very small amounts. An increase or decrease in the said amount may result in a body disorder due to hormonal imbalance.• The Reproductive System is a collection of organs in an organism that function together for sexual reproduction. The male reproductive organs are the penis, the testicles, the epididymis, the vas deferens, and the prostate gland. The female reproductive organs are the vagina, uterus (womb), fallopian tubes and ovaries.• Hormones play an important role in both male and female reproductive systems. The pituitary gland controls the functions of both the testes and the ovaries. These hormones keep the reproductive system properly functioning.• Hormones secreted by the ovaries and a small gland in the brain called the pituitary gland control the menstrual cycle.• A feedback mechanism is the process through which the level of one substance influences the level of another substance. A negative feedback affects the production of hormones in the menstrual cycle. High levels of one hormone may inhibit the production of another hormone.• Homeostasis is the state reached when each part of the body functions in equilibrium with every other part. This is attained through the regulation of the bodily functions by the endocrine and nervous systems. 186 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

Answers to Summative Assessment:I. (Understanding)1. Like the CPU, the CNS serves as the main processing center of the sys- tem. The main function of the CNS like the CPU is to process and inte- grate of information.  2. During puberty, there are significant hormonal activities occuring in the ado- lescent’s body that cause observable physical and emotional changes.3. The nervous system uses nerve impulses while the endocrine system uses hormones that normally enter the circulatory system to communicate messages.4. It is important to maintain homeostasis in the body to ensure balance and proper bodily functions in order to survive.DEPED COPYII. (Knowledge) 1. d. 2. g. 3. e. 4. c. 5. b. 6. a. 7. f. 8. h.III. (Process) • • • • • • • 187 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

GlossaryAxon the part of the neuron that transmits impulses away from the cell bodyDendrite the branch-like structure of the neuron that extends from the cell body to receive the impulseEmbryo an organism in its early stages of development, especially before it has reached a distinctively visible formDEPED COPYEndocrine Gland an organ that produces chemical secretions poured directly into the bloodstreamEgg Cell also called ovum (plural: ova); the female gameteFertilization a process that occurs when the sperm and egg combine to produce an embryoHomeostasis the ability or tendency of an organism to maintain internal equilibrium by regulating its processesHormone a chemical substance produced in the body that controls and regulates the activity of certain cells or organsImpulse an electrochemical signal moving along a neuronNeuron the basic unit of the nervous system, also called nerve cell, that transmits messages to and from the central nervous systemSemen the ejaculated fluid containing sperms and secretions from the seminal vesicle, prostate gland, and bulbourethral glandSperm shorter term for spermatozoon (plural: spermatozoa); the male gameteStimulus any factor in the environment that influences the behavior of an organismSynapse the space between neurons where electrochemical signals pass 188 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

DEPED COPYReferences and Links Printed Materials: Rabago, L., et. al., (2010). Functional Biology - Modular Approach. 2nd ed. Philippines: Vibal Publishing House, Inc Strauss, E; Lisowski, M. (2003). Biology: The Web of Life. 2nd ed. Philippines: Pearson Education Asia Pte Ltd.. Electronic Sources: (DepEd Materials) BEAM: Biology – Organ System – Endocrine and Nervous Systems EASE, Module 9: Life Support Systems EASE, Module 13: Reproductive Systems APEX Biology – Unit IV, The Organ Systems 189 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

DEPED COPY(Online Resources)ADAM Inc. (2013). Central Nervous System. Retrieved July 5, 2014 from: http://www.nlm.nih.gov/medlineplus/ency/article/002311.htmAlzeimer’s Association (2011). Three Main Parts of the Brain. Retrieved July 4, 2014 from:https://www.alz.org/braintour/3_main_parts.aspEncyclopedia Britannica Inc. (2014). Homeostasis. Retrieved July 5, 2014 from: http://global.britannica.com/EBchecked/topic/270188/ homeostasisKG Investments (2014). Stimulation Crucial to Devt. Retrieved July 3, 2014from: http://www.kidsgrowth.com/resources/articledetail.cfm?id=259MCB Berkely (2014). The Central Nervous System. Retrieved July 4, 2014 from:http://mcb.berkeley.edu/courses/mcb135e/central.htmlMissouri University of Science and Technology (n.d.). Neuroscience. Retrieved July 5, 2014 from: http://web.mst.edu/~rhall/ neuroscience/02_structure_and_pharmacology.pdfNational Center for Infants (2014). Zero to Three. Retrieved July 5, 2014 from: http://www.zerotothree.org/child-development/brain-development/Public Library of Science (2004). A Window into the Brain. Retrieved July 4, 2014 from: http://www.plosbiology.org/article/info:doi/10.1371/ journal. pbio.0020115Tamarkin, Dawn (2011). The Nervous System. Retrieved July 4, 2014 from: http://faculty.stcc.edu/AandP/AP/AP1pages/nervssys/unit10/division. htmUniversity of Texas (2012). Health Science. Retrieved July 3, 2014 from: http://teachhealthk-12.uthscsa.edu/ curriculum/ brain/brain01e-Wires. asp 190 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

Unit 3 Suggested time allotment: 8 hoursMODULE Heredity: Inheritance2 and Variation Content StandardDEPED COPY The learners demonstrate understanding of… • the information stored in DNA as being used to make proteins • how changes in DNA molecule may cause changes in its product • mutations that occur in sex cells as being inherited Overview In Grade 9, learners were able to identify characters whose inheritance does not conform to the Mendelian patterns of inheritance, solve genetic problems related to incomplete dominance, codominance, multiple alleles and polygenes; and identify the law that was not strictly followed in the non- Mendelian patterns. Learners were also able to describe the structure of the DNA and make models of DNA molecule. They also learned that the genes in their DNA influence their characteristics. In Grade 10, learners will work on activities to assess their understanding of the structure of the DNA, explain how DNA replication takes place, how RNA is made using the information from DNA, how it is transposed into proteins, and explain how mutations may cause changes in the structure and function of a protein. In this module, learners are expected to: 1. Explain how a protein is made using information from DNA. a. Identify the role of DNA and RNA in protein synthesis b. Relate DNA replication to its complementary structure. c. Trace the process of replication, transcription and translation. d. Describe the steps in protein synthesis. 191 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

2. Explain how mutations may cause changes in the structure and function of a protein. a. Compare the different types of mutations and their possible results. The key questions will be used by the teacher as a guide in planningthe lessons that are included in the Learners’ Material.Key questions for this module:DEPED COPY The pre-assessment questions will allow the teacher to discover whatis already known in a specific topic. The information gained in pre-assessmentwill be used to make instructional decision about learners’ strength and needsand determining which learners are ready for advance instructions.Answers to Pre-assessment: 1. T T G G G A C T C A G A 2. C G U U C A U G G A C U 3. Arginine Serine Tyrptophan ThreonineAnswer 192 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

DEPED COPY 4. Any change in the sequence of nitrogenous bases in the DNA, and any mistake in the transcription of genetic information from DNA to RNA or pairing of the codon and anticodon, can cause changes in the kind, sequence, and number of amino acids of proteins synthesized by cells. These changes are called mutation. Suggestion to the Teacher: Try out all activities (Activities 1 to 6) before you start with the lesson. Activity 1 Getting to Know the DNA and RNA Structures This activity is an initial assessment activity that will measure the learners’ understanding of the DNA and RNA structures. The learners are expected to compare the structures of the DNA and RNA molecule. Teaching Tips: 1. Establish the motivation for the lesson. Direct learners’ attention to the visual of the DNA molecule. (The teacher should prepare this visual ahead of time). Help the students see the “pieces” that are alike or different. 2. Ask learners to think about working on a puzzle. Prepare two separate sets of RNA and DNA nucleotides [six(6) pieces each set]. The teacher can use the DNA and RNA nucleotides on pages ___ and ___. 3. Tell one group of learners to put together the nucleotides of the DNA molecule and the nucleotides of the RNA molecule, as if fitting the pieces in a puzzle. 4. Ask learners to show their output. 5. Ask leading questions to the activity. • How is DNA different from RNA? • What nitrogen bases are found in DNA and RNA? 193 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

6. Ask the learners to work on Activity 1 individually. 7. Remind learners to answer the guide questions.Point out the location of DNA and RNA in prokaryotic and eukaryotic cells. Based on the structure of the nucleus, cells may be one of two types:prokaryotic or eukaryotic. The main difference is that the prokaryotic celllacks a nuclear membrane. Its genetic materials, which is a long circularDNA, occupies a space in the cell called nucleoid, while it is DNA occupiesa space in the nucleoid. Both the RNA and protein are synthesized in thesame compartment. Meanwhile, the eukaryotic cell, has the so called ‘true’ nucleus, whichmeans that its nuclear materials are enclosed by a nuclear membrane. Inorder to make proteins, the messenger RNA (mRNA) is assembled insidethe nucleus through transcription. The coded genetic information carried bymRNA is translated through protein synthesis using transfer RNA (tRNA).DEPED COPYAnswer to comparison table. Basis of Comparison DNA RNA1. Number of strand 2 12. Location in the cell nucleus cytoplasm3. Type of sugar deoxyribose ribose4. Nitrogenous bases A, T, C, G A, U, C, GAnswers to Guide Questions:Q1. The DNA and RNA are made up of three components: namely: a. sugar b. phosphate group, and c. nitrogenous base.Q2. DNA and RNA are different in the following: a. DNA is double stranded while RNA is single-stranded. b. The sugar in DNA is deoxyribose while that in RNA is ribose. c. The nitrogen bases in DNA are adenine (A), guanine (G), thymine (T) and cytosine (C). In RNA are adenine, guanine, cytosine and uracil.Q3. Uracil 194 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

DEPED COPY KEY CONCEPT TO EMPHASIZE: • A DNA molecule consists of two strands of nucleotides composed of sugar, phosphate, and nitrogenous bases that pair through hydrogen bonds. The paired strands form a twisted- sipper shape called a double helix. • RNA molecule is single stranded and is composed of nucletides. • RNA is three major types: mRNA, rRNA and tRNA. • In DNA, adenine bodns with thymine and cytosine bonds with guanine. • In RNA, adenine bonds with uracil and cytosine bonds with guanine. Note: The teacher may read from Biology books and Learner’s Material about replication for background knowledge. Activity 2 DNA Makes DNA In this activity, the learners will demonstrate the replication of the DNA molecule and the specificity of base pairing between nitrogenous bases. They will make a model of a DNA template to determine the sequence of bases in the new DNA strand. Teaching Tips: • Before working on the activity, introduce a reading strategy. Ask the students to study the diagram and read a paragraph about DNA replication. You may also show a DNA replication video which you can download from the YouTube. 195 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

DEPED COPY A DNA “unzips” to form two strands, as shown in Figure 1. Notice that, as the molecule unzips, the base pairs separate. Each single strand of DNA then picks up bases present in the cell’s cytoplasm. In this way, two complete molecules of DNA are created. Notice that each new DNA molecule has the same order of base pairs as the original. The copying process is called replication.Figure 1. Unzipping of DNA Molecule• After learners have completed the reading activity or viewed the video on replication, you may check for understanding. Ask the following questions: 1. Why does DNA replicate? (To produce a copy of the genetic material that will be transferred to new cells during mitosis or to new gametes during meiosis.) 2. Which nitrogen bases fit together to make base pairs? (Adenine and thymine fit together, and guanine and cytosine fit together.) 3. When a DNA molecule unzips to form two strands, what is added to each strand? What is produced? (Complementary bases attach to the exposed bases on the strands so that two complete molecules of DNA are produced.) 4. What is the copying of the DNA called? (replication) 5. How is the gene in the DNA coded? (It is usually coded by a particular sequence of base triplet called codons.) 196 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

DEPED COPY 6. In what form does a gene carry information? (A gene carries information through the sequence of nitrogenous bases that may code for RNA or amino acids in proteins.) • Determine the number of groups in your class for the activity. Ideally, about ten (10) learners or less per group. • Provide the learners with the patterns of the components of the DNA found on page ___. The other materials should have been assigned a day before the activity. • Explain the procedure of the activity; make sure that the learners will be able to follow the steps and come up with the expected output. • Check on the groups from time to time; see to it that the learners are able to do correctly Steps 3 to Step 12. • Remind them to answer the guide questions. • Ask the learners to “show and tell” something about their output. (You may decide as to how many groups will actually present). • Lead learners to the answers to the guide questions. Answers to Guide Questions: Q4. Each new strand formed is a complement of one of the original strands. The result is the formation of two DNA molecules containing the original DNA strand and the complementary daughter strands. The two new daughter strands are also complementary to each other. Q5. The two chains of nucleotides in a DNA molecule are held together by hydrogen bonds between the bases. In DNA, cytosine forms three hydrogen bonds with guanine, and thymine forms two hydrogen bonds with adenine. Q6. The pairing of the bases produces a long, two-stranded molecule that is often compare to a zipper. If you look at a zipper, the sides of the zipper represent the sugar and phosphate units, while the teeth of the zipper represent the pairs of nitrogenous bases of the DNA. 197 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

DEPED COPYQ7. Before a cell can divide by mitosis or meiosis, it must first make a copy of its chromosomes. The DNA in the chromosomes are then copied in a process called DNA replication.Q8. The variety of life forms is encoded in the DNA sequences of these organisms. More variations are alternative forms of genes cross-over and recombine in meiosis. Production of different gametes containing different sets of these genes and subsequent fusion with other gametes result to a myriad of variations in the population.• Assess the learners’ understanding by reviewing the steps of the replication process.The following events can help the learners understand how DNA copies itself:Step 1. An enzyme called helicase breaks the bond between nitrogenous bases. The two strands of DNA split.Step 2. The bases attached to each strand then pair up with the free nucleotides found in the cytoplasm.Step 3. The complementary nucleotides are added to each strand by DNA polymerase to form new strands. Two new DNA molecules, each with a parent strand and each with a new strand are formed. The DNA replication is known as semi-conservative replication, because one of the old strands is conserved in each new molecule. Figure 2 illustrates the semi-conservative replication of DNA. Figure 2. DNA Replication 198 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

KEY CONCEPT TO EMPHASIZE:• DNA is made up of nucleotides containing sugars, phosphate groups, and nitrogenous bases and its shape is double helix. The complementary structure of DNA’s two strands allow each strand to serve as a template during replication.• The specificity of base pairing in DNA, adenine with thymine, and cytosine with guanine, allows DNA to replicate itself with accuracy.DEPED COPYNote: The teacher can read from Biology books and LearnersMaterial about transcription for background knowledge.Activity 3 What’s the Message In this activity, the learners will find out how the information in DNA,which is found in the nucleus, moves to the ribosome in the cytoplasm.Learners will demonstrate the process of transcription through the use ofpaper DNA and mRNA models. Teaching Tips: • Introduce the lesson using guided inquiry to activate learners’ prior knowledge. • Establish the importance of the transcription process in gene expression. 1. What happens during the process of cell cycle? (Learners should answer that DNA is replicated and new cell structures are formed). Emphasize that DNA is already replicated before “cell division.” In eukaryotes, this process takes place in S phase of the interphase. The statement maybe applicable to bacterial cell division. 199 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

DEPED COPY• Next establish the need for mRNA to carry the genetic code from the nucleus to the cytoplasm. 1. How are proteins made? (Learners should know that proteins are made by ribosomes). 2. Where are ribosomes located in the cell? (Learners should know that ribosomes are located in the cytoplasm). 3. Where are genes located in the cell? (Learners should know that genes are located on DNA, which is located in the nucleus of eukaryotic cells and cytoplasm in bacterial cells). 4. How does the genetic code get out of the nucleus? (Learners should be able to understand that the genetic code found in the DNA sequence is “copied” or transcribed into RNA sequence. The messenger RNA leaves the nucleus and the message is translated into amino acid sequence in proteins).• Determine the number of groups in your class for the activity. Ideally, about ten (10 learners or less per group.• Provide the learners with the patterns of the components of the DNA and RNA found on pages 29 to 31. The other materials should have been assigned a day before the activity.• Explain the procedure of the activity. Make sure that the learners will be able to follow the steps and come up with the expected output.• Check on the groups from time to time, see to it that the learners are able to do correctly Steps 6 up to 9.• Remind them to answer the guide questions.• Ask the learners to “show and tell” something about their output. (You may decide as to how many groups will actually present).• Lead learners to the answers to guide questions.Q9. It resembles the complementary strand that was not used. 200 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

DEPED COPYQ10. It can be unzipped by RNA polymerase and make corresponding RNA that maybe translated proteins required by the cell. This is important to keep the integrity of the DNA as the basis of heredity but at the same time produce the products that are encoded in the genes. Q11. RNA brings the information from the DNA, which is in the nucleus, and brings it to the cytoplasm and serves as a template for protein synthesis. Q12. The messenger RNA carries the information of the gene in the DNA through the DNA-dependent RNA synthesis or transcription. In eukaryotes, the mRNA moves from the nucleus to the cytoplasm, where the information is translated into proteins with the help of ribosomes. • Assess the learners’ understanding by reviewing the steps of the transcription process. The following events will help the learners understand the process of transcription: • Step 1. RNA polymerase enzyme binds and opens the DNA molecule that will be transcribed. • Step 2. As the DNA molecule opens, the RNA polymerase slides along the DNA strand and links free RNA nucleotides that pair with the nitrogenous bases of the complementary DNA strand. Hence, if the sequence of bases on the DNA strand were CCG TTA CAT, the sequence of bases on the RNA strand would be GGC AAU GUA. • Step 3. When the process of base-pairing is completed, the RNA molecule breaks away as the DNA strands rejoin. The RNA leaves the nucleus and goes to the cytoplasm. Figure 6 shows the transcription process. 201 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

DEPED COPY Figure 3. Transcription KEY CONCEPT TO EMPHASIZE: • The order of nucleotides in DNA determines the order of nucleotides in messenger RNA in a process called transcription. • There are three types of RNA that help build proteins: mRNA, rRNA and tRNA. • mRNA carries the information in DNA, which is found in the nucleus, to the ribosomes found in the cytoplasm.After doing the three (3) activities, the learners should be able to explain thefollowing concepts: • DNA directs the production of proteins. • DNA determines the formation of mRNA. • The order of bases of mRNA determines the protein synthesized. Note: The teacher can read from Biology books and Learner’s Material about transalation for background knowledge. 202 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

Activity 4 Relay the Message In this activity, the learners will demonstrate the process of translation.Learners will find out how the message of the mRNA is translated to proteins.Teaching Tips:• Establish the conceptual relationship between DNA, mRNA and protein. 1. How do cells use DNA to make proteins? (Most genes contain the information needed to make functional molecules called proteins. Through the processes of transcription and translation, information from DNA is used to make proteins). 2. What are cell structures made of? (Proteins and other types of biomolecules including lipid, carbohydrates, and other metabolites).• Introduce the Central Dogma. Refer to Figure 4.DEPED COPY The Central Dogma of Molecular BiologyFigure 4. The Central Dogma on the Flow of Genetic Information Source: www.accesssexcellence.com 203 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

DEPED COPY• Explain that a particular gene in the DNA that code for proteins is transcribed into a single-stranded molecule called messenger RNA (mRNA). The mRNA travels out of the nucleus into the cytoplasm, where it is translated by the ribosome and transfer RNA (tRNA) molecules into a peptide sequence. Once the peptide sequence is translated, it folds into a three-dimensional protein, which acts to work or provide structure to the cell.• Before starting the activity, determine the number of groups in your class for the activity. Ideally, about ten (10) learners per group or less).• Provide the learners with the patterns of the components of the DNA and RNA found on pages __, __, and __. The other materials should have been assigned a day before the activity.• Explain the procedure of the activity, make sure that the learners will be able to follow the steps and come up with the expected output.• Check on the groups from time to time seeing to it that starting with Step 6 up to Step 9, the learners are able to do it correctly.• Remind them to answer the guide questions.• Ask the learners to “show and tell” something about their output. (The teacher can decide as to how many groups will actually present).• Lead them to the answers to the guide questions. 204 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

DEPED COPYAnswers to Guide Questions: Q13. In tRNA , the nucleotides are adenine, uracil, guanine and cytosine. The same nitrogenous bases are found in mRNA. The tRNA contains other nitrogenous bases that are derivatives of the same nucleotides. Q14. Adenine pairs with uracil and vice-versa. Q15. A codon is a set of three nitrogenous bases in mRNA which codes for a specific amino acid. Q16. Transfer RNA brings an amino acid in the cytoplasm to the ribosomes. Each tRNA molecule attaches to only one type of amino acid. Q17. In tRNA there is a sequence of three nucleotides that are complementary to the nucleotides in the mRNA codon. These three nucleotides are called an anticodon because they bond to the codon of the messenger RNA. The tRNA carries only the amino acid that the anticodon specifies. Q18. When a stop codon is reached, translation ends and amino acid strand is released from the ribosome. Q19. It resembles the job of the tRNA and the hollow blocks represent the amino acids. • Assess the learners’ understanding by reviewing the steps of the translation process. The following events in translation can help the learners understand the process: • Step 1. As translation begins, mRNA binds to a ribosome in which the ribosomal RNA is found. Then, tRNA molecules, each carrying a specific amino acid, attract the ribosome. The tRNA anticodon pairs with the first mRNA (start) codon AUG, to form the initiation complex. The two molecules temporarily join together. 205 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

DEPED COPY• Step 2. Usually, the first codon on mRNA is AUG, which codes for the amino acid methionine. AUG signals the start of protein synthesis. Then, the ribosome slides along the mRNA to the next codon.• Step 3. A new tRNA molecule carrying an amino acid pairs with the second mRNA codon.• Step 4. When the first and second amino acids are in place, an enzyme joins them by forming a peptide bond between them.• Step 5. As the process continues, a chain of amino acids is formed until the ribosome reaches a stop codon (e.g., UAA, UGA, UAG) on the mRNA strand. The polypeptide chain is released and protein synthesis is complete. Figure 7 summarizes the translation process. Figure 5. Translation Source: www. scq.ubc.ca KEY CONCEPT TO EMPHASIZE: • The process of converting the information in a sequence of nitrogenous bases in mRNA into a sequence of amino acids that make a protein is known as translation. • The role of transfer RNA (tRNA) is to bring the amino acids in the cytoplasm to the ribosomes to form polypeptides. Note: The teacher can read from Biology books and Learners Material about the Genetic Code for background knowledge. 206 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

Activity 5 Trace the Code In this activity, the learners will apply what they have learned about DNAand mRNA, and the use of the information in the Genetic Code Table. Teaching Tips:• Point out to the learners that they have only explored the overall process of transcription and translation, and that the activity will help them walk through the sequence of the DNA, transcribe it into mRNA and mRNA translating it into protein.• Introduce the Genetic Code Table to the learners.• Refer to the Genetic Code Table to identify the amino acid.• Explain the procedure of the activity.• Reproduce the activity sheet on page 209.• Illustrate an example on the board on how to locate amino acids in the Genetic Code Table below.• Remind students to answer the guide questions.DEPED COPYOrder of bases Order of bases Order of bases in Amino Acid in DNA in mRNA tRNA Coded into (codon) (anticodon) ProteinsTAG AUC UAG IsoleucineCAT GUA CAU ValineCAG GUC CAG ValineGGT CCA GGU ProlineATG UAC AUG MethionineGTT,GTC,GTA,GTG CAA,CAG,CAU,CAC GUU,GUC,GUA,GUG ValineTGA ACU UGA ThreonineACA UGU ACA CysteineAAA UUU AAA PhenylalanineGAA CUU GAA Leucine• To determine the order of bases in the first column (DNA), second column (codon), and third column (anticodon), consider the complementary base pairs in DNA: adenine pairs with thymine and guanine pairs with cytosine. While in RNA: adenine pairs with uracil and guanine pairs with cytosine.• To identify the amino acid, look at the bases in the mRNA codon, e.g., AUG using the Genetic Code Table. Look for the first letter of the mRNA codon on the left side of the Genetic Code Table (A), the second letter of the mRNA on the second column (U), and the third letter on the right column (G). AUG codes for the amino acid-methionine. 207 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

Q20. The complementarity of the base pairing is essential in transcription and translation. The final products coded by the DNA are RNA and proteins. Some of the DNA sequences are regulatory sequences that do not code for RNA or proteins but are important in gene expression. Protein synthesis is the basis of expression of hereditary characteristics in both structure and form.Q21. Each codon specifies a particular amino acid that is to be placed in thepolypeptide chain. There is more than one codon for each amino acid.• Assess learners’ understanding by giving an example of a DNAsequence on the board. Ask one volunteer to transcribe it into mRNAsequence and another volunteer to translate it into protein one codonat a time.DEPED COPYExample:DNA sequence: AGACTTATCmRNA sequence: UCUGAAUAGPROTEIN: Serine – Glutamic acid – Stop codon• Ask students about the function of the ‘STOP’ codon to check forunderstanding.• Lead learners to the next lesson by asking them what will happen ifthe first C in the sequence is changed to G. Learners are expectedto answer that the protein sequence would be changed. This is anexample of mutation.• Tell the students that they will be learning about mutation in the nextlesson. 208 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

Name: _________________________________ Section: ___________ Activity 5 Trace the CodeOrder of bases Order of bases in Order of bases in Amino Acid Coded in DNA mRNA (codon) tRNA (anticodon) into Proteins TAG AUC CAT Methionine GUC Valine ACA CCA AAA GAA ACU UGU CUUDEPED COPYGenetic code Table Q22. Why is the specific base pairing essential to the processes of transcription and translation. ________________________________ Q23. How many codon/s codes for one amino acid? _______________________________________________________ 209 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

Activity 6 Chromie Change In this activity the learners will illustrate and differentiate the kinds ofchromosomal mutations.Teaching Tips: • Introduce the lesson using guided inquiry to activate learners’ prior knowledge. • Establish the motivation for mutation lesson. 1. How do errors in base pairing of the DNA change the DNA sequence? (Different protein that is usually non-functional or with altered function will be made). 2. What do you call these changes? (Mutation) 3. What might cause a mutation to occur? (Mutations may be caused by mutagens in the form of radiation, chemicals, extremes of temperature, and even viral infection). • Determine the number of groups in your class for the activity. Ideally, about ten (10) learners or less per group. • Explain the procedure of the activity. Make sure that the learners will be able to follow the steps and come up with the expected output. • Check on the groups from time to time, see to it that the learners are able to do it correctly. • Remind them to answer the guide questions. • Lead learners to the answers of guide questions. • Guide the students in filling out the table below. Refer to the possible answers in the table.DEPED COPY Chromosomal Mutations Translocation Deletion Inversion1. How many 2 11 Broke a part Broke a part,chromosome/s is/are reversed andinvolved? reinserted it into2. How did you change Broke a part the the original structure and chromosome of the chromosomes? attached it to another chromosome. 210 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

3. Which condition/s Either gain or Loss of Either gain or do you think loss of genetic genetic loss of genetic result/s to change/s material OR no Material material OR no of chromosome loss or gain of loss or gain of material? Please genetic genetic material indicate using the material during the words loss, gain, during the process either loss or gain of exchange genetic material. process Answers to Guide Questions:DEPED COPY Q24. Translocation occurs when a piece of chromosome breaks off and attaches to another chromosome. An inversion involves the breakage of a chromosome in two places in which the resulting piece of DNA is reversed and re-inserted into the chromosome. Deletion refers to the loss of a segment of DNA or chromosome. Changes that affect the structure of chromosomes can cause problems with growth, development, and function of the body’s systems. These changes can affect many genes along the chromosome and disrupt the proteins made from these genes. Q25. The normal genetic content of the chromosome may be affected. Many diseases are caused by the effects of inherited genes. In most cases, there is only a small difference between the DNA sequence in the defective gene and a normal one. This difference is enough to cause serious and often fatal diseases. Q26. Gain or loss of chromosome material results in chromosomal mutations or aberrations; may also result to Down’s syndrome, Klinefelter’s Syndrome, or Turner’s Syndrome. However, Cri-du-chat Syndrome is due to loss of chromosome. Q27. The possible effects of chromosomal mutations are medical problems, problems on growth and development, genetic disorders, and even death. • Assess the learners’ understanding by showing a drawing of the four kinds of chromosomal mutations. Let learners analyze and identify the type of chromosomal mutation. • Show a normal male and female karyotype and some examples of karyotypes of chromosomal abnormalities, e.g. Down’s Syndrome, Cri-du-chat, Klinefelter’s syndrome and Turner’s syndrome. Let learners compare the normal karyotype with the karyotype of affected individuals. Let them identify which set of homologous chromosomes are affected. • Conclude the lesson by asking learners if their knowledge of molecular genetics may affect their lives. Ask for some volunteers and listen to their thoughts and ideas. 211 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

• Point out to the learners that in agriculture, traits of plants and animalscould be modified by targeted or random mutations and that not allmutations are harmful.• Mention to the learners the concept about genetic engineering. Inrecombinant DNA technology, scientists have developed methodsto move genes from one species into another. This process usesrestriction enzymes to cleave one organism’s DNA into fragmentsand other enzymes to splice the DNA fragment into a plasmid or viralDNA. Transgenic organisms are able to manufacture genetic productsalien to themselves using recombinant DNA. Genetic engineeringhas already been applied to bacteria, plants, and animals. These organisms are engineered to be of use to humans.• Access additional resources about genetic engineering on this linkDEPED COPYwww.worldofteaching.com• Cite the work of Luther Burbank, an American horticulturist whointroduced more than 200 varieties of fruit. The teacher can tell thelearners that he developed pomato (tomato/potato), plumcot (plum/ apricot), and the white raspberry. The teacher can localize examples.• (Optional)Have students think about a hybrid fruit, vegetable, floweror animals that they might like to breed. Let them draw pictures oftheir hybrid organisms considering the qualities that they would like their hybrid organisms to have.• You may use the given sample rubric for this task or you may createyour own rubric.Suggested website for hybrid fruits and vegetables: (www.buzzle.com/articles/hybrid-fruits-and-vegetables.html)Note: The teacher can acces the LRMDS(BEAM) material ofDepEd from which Activity 6 was adapted. KEY CONCEPT TO EMPHASIZE: • A mutation is a change in the base sequence of DNA. Mutations may affect only one gene, or they may affect whole chromosomes. • Mutations in eggs or sperm effect future generations by producing offspring with new characteristics. • Mutations in body cells affect only the individual and are not passed on to the offspring. • When DNA from two different species are joined together, it is called recombinant DNA. This process uses restriction enzymes to cleave one organism’s DNA into fragments and other enzymes to splice the DNA fragment into a plasmid or viral DNA. 212 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

Name: _______________________________ Date: ________________Grade: _____________ Teacher: _________________________________ RUBRIC Performance Criteria Value Indicator 1 234Creativity andOriginality Finished the Includes an Includes some Includes many piece of drawing idea, unique ideas unique ideas but but lacks and several and provides no originality and materials were creative use of evidence may have used, based his materials, made of creativity or imitated or her work on connections originality someone else’s someone else’s to previous plan idea; made knowledge,DEPED COPY decisions after generating referring to one many ideas sourceConcept Piece was not Piece was Piece was Piece was well-understanding created at all created but created to show planned and unclear desired traits of created to show the hybrid animal desired traits or plant crops of the hybrid animal or plant cropsEffort Did not finish Finished the Completed the Gave effort far the work in a project, but it project in an beyond the satisfactory lacks finishing above average requirements of manner touches or can manner, yet the project be improved more could have with little effort been done/ developed/ accomplishedResponsiveness Displayed Displayed Displayed Displayed a negative a negative a positive a positive response response at response most response all the throughout the times during the of the time time during the development of development of during the development of the piece the piece development of the piece the piece TotalTeacher Comments: 213 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

DEPED COPYSUMMARY • DNAis the genetic material of organisms.ADNAis a double helix molecule composed of two complementary strands of deoxyribonucleotides units. The complementary base pairs of the DNA are held by hydrogen bonds. • The central dogma of the transfer of genetic information states that the sequence involved in the expression of hereditary characteristics is from DNA to RNA to proteins. • Genes are segments of DNA that may code for RNA or proteins. • Most sequences of three bases in the DNA of a gene code for a single amino acid in a protein. • Transcription is the process by which the information in a strand of DNA is copied into a new molecule of messenger RNA (mRNA). • There are three major types of RNA in the cell and their functions: 1. mRNA carries the information from DNA to the ribosomes. 2. tRNA translates the genetic message carried by the mRNA through protein synthesis. 3. rRNA forms the structural component of the ribosome. • Ribosomal RNA serves as the site for attachment of mRNA and tRNA and for protein synthesis • Translation is a process which the order of bases in mRNA of amino acids is synthesized/converted/decoded into a protein. It occurs in a ribosome of the cytoplasm. • A mutation is a change in the base sequence of DNA. Mutations may affect only one gene, or they may affect whole chromosomes. • Mutations in eggs or sperm may affect future generations by transmitting these changes in the offsprings. Mutations in non-sex (somatic) cells only are not hereditary. • When DNA from two different species are joined together, it is called recombinant DNA. This process uses restriction enzymes to cleave one organism’s DNA into fragments and other enzymes to splice the DNA fragment into a plasmid or viral DNA. 214 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

Answers to Summative Assessment:A. 1. (a) TTACGGTCACCA 2. (a) (c) UUACGGUCACCA 3. (b) AAUGCCAGUGGUB. 4. UGG 5. 6 6. Aspartic acid 7. U & A C. Arrange the following steps in protein synthesis from first to last (1-6). 1 A. Transcription 3 B. tRNA – amino acid units link to mRNA 4 C. Amino acid separate from tRNA 5 D. Polypeptide chain assembled 2 E. mRNA links to ribosome 6 F. Stop codon encountered in mRNADEPED COPYD. Given the list of amino acids, determine the sequence of bases in the codonof the mRNA that codes for these amino acids. Use the table for theGenetic Code1. AUG 6. AAU/AAC2. UUA/UUG/CUU/ 7. GUU/GUC/GUA/GUG CUC/CUA/CUG3. AGA/AGG 8. GGU/GGC/CGA/GGG4. ACU/ACC/ACA/ACG 9. GAU/GAC5. AAA/AAG 10. GAA/GAG DNA Template E. AUG UUA AGA ACU AAA AAU GUU GGU GAU GAA Note: The teacher should consider that there are other possible answers to be presented by students since one amino acid maybe coded by several codons. 215 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

Glossary of TermsDNA replication process in which the DNA is copiedAmino acid the building blocks of a protein moleculeAnticodon the complement of the mRNA triplet code in the tRNAChromosomal changes in the chromosomes where parts mutations of the chromosomes are broken off and lost during mitosisDEPED COPYCodon each set of three nitrogenous bases in mRNA representing an amino acid or a start/stop signalGenetic code set of rules that specify to the codons in DNA or RNA that corresponds to the amino acids in proteinsNitrogenous base is a carbon ring structure that contains one or more atoms of nitrogen. In DNA, there are four possible nitrogen bases: adenine(A), thymine(T), cytosine(C) and guanine(G).mRNA messenger RNA; brings information from the DNA in the nucleus to the cytoplasm.Mutation Any change in the DNA sequenceRecombinant DNA A form of DNA produced by combining genetic material from two or more different sources by means of genetic engineering.rRNA ribosomal RNA; hold tightly to the mRNA and use its information to assemble amino acids.tRNA transfer RNA; a type of RNA that attach the correct amino acid to the protein chain that is being synthesized in the ribosomeTranscription process of copying DNA sequence into RNATranslation process of converting information in mRNA into a sequence of amino acids in a protein 216 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

DEPED COPYReferences and Links Books Rabago, L., et.al. (2010).Functional Biology:Modular Approach.Vibal Publishing House, Inc. Biggs. A. Gregg, K., et.al. (2000).Biology: the Dynamics of Life. USA: McGraw - Hill Companies. Inc. Addison-Wesley (1996). Science Insights:Exploring Living Things. USA: Addison Wesley Publishing Company. Teaching Guide – Integrative Science Biology by Eferza Publications Internet www.chemguide.co.uk/organic props/amino acids/dna1.html/ www.accessexcellence.org www.elmhurst.edu ghr.nlm.nih.gov/handbook/mutations and disorders/gene mutation www.nature.com/scitable/topicpage/Genetic-Mutation - 1127 www.buzzle.com/articles/hybrid-fruits-and-vegetables.html DepEd Materials APEX Biology Unit 6 Anatomy of Genes Lessons 1-5 Heredity and Genetics BEAM Learning Guide, Nov.2008, Genetic Book of Life pp. 28-34 EASE Biology Lesson 3 The DNA Material pp. 20-24 217 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

DEPED COPY DNA Template 218 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

DEPED COPY RNA Template 219 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

DEPED COPY tRNA Template 220 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

Unit 1 Suggested time allotment: 8 hoursMODULE Biodiversity and3 EvolutionContent Standards Performance StandardsDEPED COPYThe learners demonstrate the The learners write an essay orunderstanding of how evolution make a multimedia presentation onthrough natural selection can result the importance of adaptation as ato biodiversity. mechanism for survival of a species.Overview From Grade 7 to Grade 9, the students learned that organisms aregrouped into Kingdom, Phylum, Class, Order, Family, Genus and Species. Theyalso learned that organisms possess unique qualities. Some organisms maylook the same but they are totally different from one another, e.g. shark anddolphin; others may be related to one another but they have different physicalfeatures and characteristics, like bat and rodent. This is because organismschange over time. When climate changes, the environment will also changeand so with organisms living in that environment. Some changes are easilynoticeable. While other changes occur so slowly through time and not easilynoticed. In Grade 10, learners will realize that individual differences and varietyof characteristics are important to ensure the survival of species. The presenceof advantageous and desirable traits allow organisms to survive naturalcalamities, disaster, and changes in the environment. This year, the students will learn how fossil records, patterns indevelopment, and molecular data could be used to study the concept ofevolution. They will also be provided with a variety of activities to help themunderstand the general processes and mechanism of evolution believed toproduce the Earth’s biodiversity. 221 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

Moreover, they will realize that the gift of human intelligence and abilitiescarries great responsibility to protect life and the environment, and to increasebiodiversity. At the end of this module the learners are expected to: 1. Understand how evolution is being studied from the fossil record and molecular data. 2. Give the importance of understanding the origin of life. 3. Explain why reproduction, variation, and adaptation are necessary for the survival of species. 4. Discuss how natural selection promotes expression and propagation of traits, and species that adapt with the changing environment. Key questions for this module:DEPED COPYPre-assessment is given as a tool to measure the learners’ prior knowledgeabout Evolution.Answers to the Pre-assessment1. A 6. D2. C 7. A3. B 8. A4. D 9. C5. B 10. DII. Note: Instruct the learners to use line graph for graphical representation of the given situation.1. b. 222 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

DEPED COPYIII. Patterns of Evolution. 1. Divergent 2. Convergent Sources of Evidences in the Study of Evolution Organisms inhabiting the earth have changed overtime. Their structures, traits and abilities allowed them to adapt and survive in their environment. Data from the fossil records, anatomy and morphology, embryonic development, and biochemistry could be analyzed to demonstrate if evolution of life on Earth has taken place. Evidences from Fossil Records Teaching Tips: • You may start the lesson by showing a picture of fossil remains as a motivation. • Explain that fossils are examples of materials that paleontologists use in studying evolution; they are traces of organisms that lived in the past and were preserved by natural processes or catastrophic events in rocks, peat, or ice; some fossils are remains of organisms, that include bones, shells, teeth and also feces (coprolite). Through time, the fossil-bearing rocks were exposed by movement of the Earth’s surface, by weathering, or dug out by paleontologists. KEY CONCEPT TO EMPHASIZE: Most fossil remains are commonly found in sedimentary rocks; they are from the hard parts of the organism like woody stem, bones, or teeth. Determining the age of the fossil Activity 1A should enable the students to estimate the age of fossils by their positions in the sedimentary rock. Teaching Tips: • Explain that fossils are formed from remains of organisms which were buried in layers of sedimentary rocks due to catastrophic events and natural geologic processes. In time, these remains were replaced by minerals forming rock like materials known as fossils. 223 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

DEPED COPY • In your discussion, state that relative dating is a method used to determine the age of the rocks by comparing them with the rocks in the other layers. The younger rock is found on the top layer and the older rock is found in bottom layer. Mention also that relative dating method depends upon the assumption that the age of a fossil is based on the relative age of the rock from which they are found; the technique is also used to date the rock based on the fossil it contained. This makes the method unreliable and require Carbon -14 dating, other radioisotopes dating, and molecular techniques. • Point out that some fossils have no living representatives today due to extinction. By comparing the fossils in the different rock layers, scientists were able to predict the changes that occurred in the characteristics of various organisms and to reconstruct the order of changes that these generations of organisms have undergone. • The teacher may ask the learners to draw a rock layer and put the four examples of fossils in every layer. Then the teacher can ask the learners these questions: a. Which of the fossils is found at the deepest layer? b. Which is found at the uppermost layer? Explain your answer.Activity 1A Where Do I Belong Images of trilobite and crinoid stem taken from The Virtual Petrified Wood Museum 224 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

DEPED COPYQ1. The oldest organism in the list are the trilobites, (answers may vary). They lived during Paleozoic Era, in the Silurian and Ordovician period. They can be 600 million years old. Q2. Cenozoic Era, the recent fossil may be found in the uppermost layer of the rock. (Answers may vary). Q3. Yes. Rock layers in the Cambrian period also have traces /imprints of mollusks that lived during that time. Most of them were invertebrates. (Answers may vary). Q4. Cenozoic Era, the fossil of the first human was found during this Era. Q5. Organisms are arranged from invertebrates to vertebrates, from simple organisms to complex organisms and from unicellular to multicellular. (Answers may vary). KEY CONCEPT TO EMPHASIZE: Paleontologist determine the age of the fossils through their positions in the sedimentary rocks. Fossils found in the bottom layer are assumed to be older than those found in the upper layers. In the next activity, the learners will determine the age of fossils by checking its amount of radioactive Carbon-14. Teaching Tips: • You may mention another method of determining the age of fossils, and that is through the use of radioactive isotopes. This is done by analyzing the age of the fossils and rocks where the fossils were found, using the rate of decay of certain radioactive isotopes. This is called absolute dating technique. • Explain how the examination of layers of rocks and dating fossils allowed scientists to develop the Geologic Time Scale. The Geologic Time Scale proposes the major events in the earth’s history. It also suggests the appearance of various kinds of organisms in a particular period of time on earth. • You may discuss the Geologic Time Scale and highlight the notable dominant life forms in every period and era. Allow the students to gauge the environmental and climatic conditions in every era, and relate them to the kind of organisms that existed during that time. 225 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

DEPED COPY• Explain how the Geologic Time Scale might be used to determine the approximate age of the Earth, estimated to be around 4.6 billion years old. The information given by radioactive dating of the fossils, along with observations of rocks and rock layers, enabled the geologists to speculate on the history of life on our planet. • You may end the lesson by asking the students to reflect on this situation: You have been given an opportunity to travel in the future for severalhundred years. Use your imagination to think of organisms that might be livingon earth in that particular time, considering the environmental disturbances,calamities, and changes that occurred.Activity 1B What’s My Age?Note: In this activity, you may allow the learners to use calculator.Activity taken from Payawal P. (1993)Q6. The age of the oldest fossil is 17 190 years old, a petrified wood.Q7. The age of the fossil will determine the particular Era or Period the organisms existed on earth. 226 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

Evolutionary Patterns from Comparative Anatomy Another evidence of evolution is from comparative anatomy. Structurescan be homologous or analogous.Teaching Tips:• Point out that divergent evolution proposed that homologous structures that developed from common ancestors may have different functions, such as bat wings and rodent forelimbs. On the other hand, convergent evolution suggest that analogous structures of organisms of different ancestors have similar function such as butterfly wings and bird wings.DEPED COPY• You may refer to the diagram below, for comparison between homologous and analogous structures.Comparison between Homologous and Analogous StructuresBasis of Comparison Homologous Structure Analogous structureOrigin Have the same ancestor . Have different ancestorsFunction Modified to perform Adapted to similar different functions functionsExample Forelimbs of bat and Wings of birds, bat and whale butterflyQ8. The teacher can ask the learners to research examples about analogous structures. (Answers may vary). The next activity will help the learners understand the importance ofcomparative anatomy in the study of evolution. 227 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

DEPED COPYActivity 2 AHA! Analogous! Homologous!Directions: Write, in the space provided, H if the structures below arehomologous and A if they are analogous. H H H AActivity from Payawal P. (1993)Q9. Yes, because their forelimbs are made up of same kinds of bones that just vary in size and function differently, suggest that they share a common ancestor.Q10. The teacher can assign the students to do some research to determine examples about homologous structures. (Answers may vary). To summarize the lesson, you may ask the students this question: Whatis the relevance of homologous structures in studying divergent evolution, andanalogous structures in studying convergent evolution?Patterns in Embryonic Development The next activity is about the comparison of the embryonic developmentof different organisms. This activity will help the learners understand howembryonic development provides patterns in the concept of evolution andrelatedness of certain animals. 228 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

Teaching Tips: • Start the activity by asking the following questions: o Who is your relative? Why is it important to know your relatives? • Explain that as the organisms grow and develop, the embryos gradually become more and more dissimilar. These differences in form are caused by genes that were turned on in the process of development through time. Differences in the form are controlled by the genetic blueprint of the organisms; and mutations in some of these genes may lead to congenital defects, physical abnormalities, cancer, and predisposition to infection. Yet on some very rare occasions minor mutations promote desired trait for growth or resistance to disease.DEPED COPYActivity 3 So, Who is My Relative?Q11. The first and second stages of development of the organisms show better similarities.Q12. Possible answers: the shape of head, lower parts of the body, and forelimbs.Q13. Possible answers: organisms are different in size, shape of the head, hind limbs, forelimbs, structure of the eyes, etc.Q14. Similarity in structures may suggest that organisms share common ancestors. (Answer may vary). KEY CONCEPT TO EMPHASIZE: Species that are closely related exhibit similar embryonic development although in the adult stage the organisms are quite different.Evidence from Amino Acid Sequence Another area of study in the evidence of evolutionary concept is providedby protein and DNA sequences. The next activity will further help learnersunderstand more about the relationship of organisms based on their moleculardata. 229 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

Teaching Tips: • Start the session with a review on DNA, protein structures, and relationships learned in module 2. • For tables 2, 3, 4, the teacher can ask the students to highlight the different amino acid by using other colors of pen. • For graphical representation of tables 6 and 7, you may ask the students to use different colors to represent pairing of species. • You may ask the learners to analyze the results and interpret the graphs, and discuss the results. • The teacher may assign the students to search about the theory of Jean Baptiste de Lamarck and Charles Darwin. Allow the students to organize their readings about Jean Baptiste de Lamarck and Charles Darwin in foldable as shown below (Figure 1). Figure 1DEPED COPYActivity 4 Let’s CompareTable 2 Table 3 230 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

DEPED COPYTable 4 Table 5 Activity taken from Brittain T. (Biology the Living World) Lab Manual, 1989 Q15. Chimpanzee Q16. Kangaroo Graphs for Table 6 and Table 7 231 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

DEPED COPYQ17. Bread molds, with 48 differences in amino acid sequence.Q18. Fruit fly and screwworm Fruit fly and wheat, with 47 differences in amino acid sequence.Q19.Yes, the similarity in amino acid sequence may suggest similarity in their DNA sequence.Q20. Yes, similarity in amino acid sequence may suggest the closer relationship of the organisms. KEY CONCEPT TO EMPHASIZE: DNA and amino acid sequences maybe explored to investigate evolutionary concepts. These tools may provide identify and are used in the classification of organisms to their respective genus and species. Activity 5 Follow the track Activity 5 is a simple simulation of natural selection using footprints oftwo different organisms. Encourage the students to use their imagination tocreate a story out of the footprints.Teaching Tips: • This activity is best carried out in groups. Two days before the lesson, assign each group to interpret or create a story out of the four diagrams. • Allow the group to present their work in class. You may choose the best story. • During the activity, it helps if you will post on the board an illustrations of the activity “Follow the Track” especially during group presentation. • During the discussion, point out that organisms struggle for existence in order to survive; they compete for food and space. Organisms with favorable and advantageous characteristics survive and reproduce. Fitness refers to the ability of an organism to survive and produce offsprings. Different individuals in a population possess different characteristics and abilities; this is called variation. 232 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

Answers to Guide Questions:Q21. Two sets of footprints. Yes, the footprint on the left belongs to smaller organisms, while footprints on the right belong to much bigger organisms.Q22.They are both going to the same direction.Q23. Possible answers: in diagram 3, a struggle between the two organisms. In diagram 4 (Answers may vary), the organism with advantageous characteristics survived. The smaller organisms did not survive. The next activity will help the learners determine the effect of environmentalchanges on adaptation and survival of species.Activity 6DEPED COPY SurvivorTeaching Tips: • This activity is best carried out in groups. You may assign learners to read and study activity 6 in advance to give them time to prepare the materials. • Guide the learners through the procedure. There may be steps in the procedure where closed supervision is needed, such as using the alcohol lamp and removing the burnt materials. • Remind the learners about laboratory safety. • Make sure that the students are wearing their masks before using the alcohol lamp. • During the activity, students must use tongs or clamps to remove burnt materials. • The teacher may ask the students to present the results in front of the class for discussion. • You may use the table below, in determining the survivors. Basis of determining survivors: 233 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.

Events Survivor Not a SurvivorFire (Alcohol lamp) Materials that did not burn All burnt materialsEarthquake ( Magnet) Materials not attracted to Materials attracted to the magnet the magnetFlood ( Water) Materials that are wet but All wet and destroyed not destroyed materials DEPED COPYSample results FIRE Disturbances Flood/ Total number (alcohol typhoon of survivors Organisms/ Earthquake (Water) Events lamp) (Magnet) 25 or more 6 25 0 Marbles 18 0 Paper 0 0 0 0 Candles 0 18 Plastics 0 0 0 Paper clips 2 0 0 6 6Q24. Answers can be marbles and paper clips (Results may vary).Q25. Yes, possible answers are paper, plastics or candles (Results may vary).Q26. Marbles and paper clips were able to survive because they possess characteristics that can withstand the three environmental disturbances. The papers, candles, and plastics don’t have characteristics that can help them survive the three environmental disturbances (Answers may vary).Q27. Variation increases the chance of survival. Organisms with the most desirable traits would likely survive environmental changes and gradually become better suited to survive in a given environment; this is called adaptation. 234 All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.