Biology Distance Learning Plan Week 6

Student Name Teacher Name

District of Columbia Public Schools | SY 2019-2020 Science Distance Learning Plan

Introduction

Dear Students and Families,

We hope you have found a routine for distance learning and taking care of yourself.

You will notice that beginning this week your assignments will shift completely to new content that you did not previously learn in class. In most cases, you will continue to see your assignments grounded in a Mission and culminating with the completion of an Action Plan. In order to gain information to complete your Mission log and Action Plan you will complete readings, videos and hands-on activities.

The assignments for this week were designed to take four days to complete. The recommendation of 40 to 60 minutes per day per subject, four times per week continues. Activities are organized and labeled by day.

Week 6: Evidence of Common Ancestry This week you will be studying common ancestry between organisms.

As you work toward this goal, you will be learning the following concepts: Common ancestry between organisms can be supported by different evidence, such as: DNA sequences, Anatomical structures, and Anatomical structures in embryological development.

As you complete assignments this week, the STEMscopedia will be the primary text within STEMscopes, your science curriculum resource. You have likely been reading excerpts from it all year. You can access the STEMscopedia on STEMscopes via Clever. Sections relevant to this week are also posted online at http://bit.ly/DCPSscienceathome.

Using STEMscopes via Clever By default, the STEMscopedia is turned on for all units. Your teacher does not need to assign it to you. You can access STEMscopes online through Clever. • Go to https://clever.com/in/dcpsk12 • As your username, use your DCPS student ID number. • As your password, use your date of birth(mmddyy). • Find the “STEMscopes” icon to get started. • Select “Learning Resources” at the top of the page. • Search for the name of the topic you are studying (e.g., Evidence of Common Ancestry).

District of Columbia Public Schools | SY 2019-2020 Science Distance Learning Plan

Week 6- Day 1: Accessing Prior Knowledge and Video Activity

Today’s Assignments 1) Read over Mission Briefing. You will complete the Mission Log -Part 1 at the end of the week. 2) Complete Accessing Prior Knowledge Activity 3) Watch What is Common Ancestry? Video and complete notes and summary ______

Mission Briefing Anchoring Phenomena Rabbits and hares have commonly been confused for one another for many years. Some have common names that even call them the opposite of what they are. However, they have some very distinct features about them that cause them to be different. Are these differences enough to consider them different species?

Mission Briefing You are an ecologist who is in charge of comparing the four main species of rabbits and hares in North America, determining if there is enough evidence to suggest that they have a common ancestor, and explaining your findings. You will also use statistical strategies to determine how a new adaptation will affect a rabbit population.

● What does it mean when two organisms have a common ancestry? ● What is evolution? ● What is natural selection? Science Distance Learning Plan

What evidence of common ancestry can be seen in the structures above?

What common functions do the structures share? Science Distance Learning Plan

What is Common Ancestry? Video https://www.youtube.com/watch?v=Gi86jDjKu-c

Video Summary and Key Points

Week 6- Day 2: Hook Activity

Today’s Assignment 1) Complete Hook Activity- Cladogram Evidence of Common Ancestry

Cladogram

Description of Species Picture

Species 1: The organism has a single antenna that is branched (like a Y). It has two eyes positioned on top of the head of a nonsegmented body.

Species 2: Fossils of this species date back 8,000 years. This organism has branched antennae and three body segments. The middle segment has fleshy appendages with a bendable joint.

Species 3: The organism has a branched antenna (like a Y). Its body is divided into two segments and its eyes are positioned on top of a head.

Species 4: This organism has branched antennae, two body segments, and eyes positioned on top of a head. The fleshy appendages on the last segment have a bendable joint.

Species 5: Fossils of this species date back 50,000 years. The organism has a single antenna, two eyes positioned on top of a head, and a nonsegmented body.

Species 6: This organism has branched antennae, two body segments, eyes positioned on the top of the head, and small fleshy appendages on the last segment.

1 Evidence of Common Ancestry

In cladistics, similar characteristics that come from a common ancestor are used to divide organisms into groups. A cladogram will begin by grouping organisms based on a characteristic displayed by all the members of the group. The larger group, or clade, will contain increasingly smaller groups (clades) that share the traits of the clades before them. They also exhibit distinct changes as the organism evolves. All descendants to the right of a branch-point share that new feature; none of the creatures to the left do.

1. From the organisms shown on Page 1, determine features that are shared among the organisms and those that are unique. Use this information to fill out the table below.

No Legs, Legs, Non-branched or Number of Body Species Two Eyes and/or Jointed Branched Antennae Segments Legs

2. Use the characteristics (morphologies) in your data table to determine the positioning of the species on the cladogram you will create. You will draw organisms that are ancestral on the left of the cladogram, and more recently evolved organisms toward the right. 3. Include on your cladogram the following: a. Determine where you think each species should be placed.

b. Write the species number on the branch where you believe it belongs.

c. Label the arrows along the bottom of the tree with the characteristic that is shared with the clade above or to the right of it.

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4. On your cladogram, circle the clade of organisms with two body segments. A clade is a grouping that includes a common ancestor and all of its descendants (living and extinct).

3 Week 6- Day 3: Explore Activity

Today’s Assignment 1) Complete Explore Activity: Evidence of Common Ancestry Stations (Station 1 and Station 2)

Evidence of Common Ancestry Stations

Scientists have long wondered where organisms came from and how they evolved. One of the main sources of evidence for the evolution of organisms comes from the fossil record. Thousands of layers of sedimentary rock provide evidence not only of the history of Earth itself, but also of changes in organisms whose fossil remains have been found in those layers. It documents the existence, diversity, extinction, and change of many life-forms throughout the history of life on Earth.

The fossil record includes the total number of fossils that scientists know of as well as their locations in rock formations and the sedimentary layers. Their locations in the rock layers is important, as it shows how long ago those organisms lived. This record provides a wealth of information about the organisms that existed in the past. It also suggests that many of these organisms have distant ancestors dating back hundreds of millions of years.

Fossil remains have been found in sedimentary rocks of all ages. Patterns of fossil occurrence help geologists identify the sequence of events that led to the formation of that fossil. For example, fossils of the simplest organisms are found in the oldest sedimentary rocks buried in lower layers, while fossils of more complex organisms are found in the newest rocks in top layers. This is evidence for the theory of evolution, which states that simple life-forms gradually evolved into more complex ones. The chronological order of rock layers is usually determined by their order in an undisturbed sequence of strata. In undisturbed sedimentary rock, the oldest layers would be found at the bottom, and the youngest layers at the top. In disturbed rock layers, the determination must be made based on the presence of index fossils, comparison to undisturbed strata, or radiometric dating.

Scientists have discovered that there was a sudden increase in the diversity of organisms found in the fossil layers within the fossil record around 530 million years ago. This time frame is referred to as the Cambrian explosion. During this time, the diversity of life on Earth increased dramatically. Most of the major phyla that we see today came into being after the Cambrian explosion. Scientists agree that the organisms that came into being after the Cambrian explosion must share common ancestors with the organisms that came before this time.

The fossil record, however, is not the only evidence that supports the common ancestry of organisms. We also see this evidence in similarities in characteristics between organisms, known as homologies, that may have originated from a common ancestor. A homologous structure is something that is similar in position, structure, or evolutionary origin between organisms. There are three main categories of homologies among organisms: anatomical, developmental, and molecular. You will examine all three types of homologies in this activity.

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Station 1: Anatomical Homologies

In this section, you will explore anatomical homologies by examining the structure of vertebrate forelimbs. Look at the human forelimb in this diagram and study its bone structure. You will use this information to help you analyze the bone structure of some other mammals. You will then evaluate their similarities as possible evidence of common ancestry. You will do this by building the skeletal structure of their forelimbs and then demonstrating how the scapula, humerus, radius, ulna, carpals, metacarpals, and phalanges share common placement between vertebrate species.

1. Scapula 2. Radius 3. Phalanges (finger bones) 4. Humerus 5. Ulna 6. Carpals (wrist bones) 7. Metacarpals (bones in the palm of your hand)

Directions 1. Locate the diagram of the human forelimb along with its title. Study the human forelimb structures as labeled above in this activity.

2. Color the human forelimb on the next page according to the labeled diagram above. You will use this as a guide to help you identify the bones for the other animals shown.

3. Color and label the forelimbs for each of the other animals. Once completed look for similarities in the bone structure between each animal.

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Student Reference Sheet Station 1

1 Evidence of Common Ancestry Explore 1

3 Evidence of Common Ancestry Explore 1

Station 1: Anatomical Homologies Questions 1. How is the human forelimb similar to that of the other three mammals you examined? Be specific.

2. Why might this evidence suggest a distant common ancestry between different vertebrate species? Explain your answer.

3. Analyze the forelimbs you colored and labeled. What similarities would you expect to find in the forelimb of another vertebrate species, such as a gecko or ferret? Identify these similarities and explain why these similarities might exist.

Directions: Read the following passage, then continue on to complete questions 4 through 6. As you have just learned, anatomical homologies are similar anatomical structures that exist between species that can be identified as a link to a common ancestor. Similar features suggest relatedness among the organisms. Anatomical homologies are sometimes easy to observe, as is the case with modern Asian and African elephants and the now-extinct wooly mammoth. All three are distinct species, but they belong to the same family of organisms that have large skeletons, trunks, and tusks (Elephantidae).

Mammals are a class of organisms that all share certain traits, such as breathing air, having hair or fur, and producing milk for their young. As you have already seen, all mammals show similar patterns of bone structures in their forelimbs. However, mammals have forelimb structures strikingly similar to other types of animals, including birds and reptiles.

4. What is a homologous structure, and what are some examples?

5. Humans are mammals, which are defined as having a certain set of anatomical homologies. What are some homologous structures shared by all mammals? List them.

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6. What occurred during the Cambrian explosion? How is this significant in terms of common ancestry?

Station 2: Developmental Homologies

At this station, you will examine some hand-drawn pictures of early embryonic development of seven different animals. These images are by no means 100% accurate, but these are the types of tools that early scientists used when comparing animals that may share common ancestry.

Directions Using the images found on the Student Reference Sheet for Station 2, fill in the table below by placing the number found below each picture in the space of the correct animal at each stage of development. You may want to use a pencil for this, as your answers may change as you examine each image.

STAGE OF FISH TORTOISE CALF HUMAN CHICK RABBIT SALAMANDER DEVELOPMENT

STAGE I

STAGE II

STAGE III

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Station 2- STUDENT REFERENCE SHEET

Stage I Development

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Station 2: Developmental Homologies Questions

1. What did you notice as you were trying to match the images of each stage of development to the correct animal? Was it difficult? What were some of the challenges in doing so?

2. After you have matched the cards, describe some of the similarities that you found among the embryos of the seven different animals.

3. Explain how the similarities in early embryonic development may point to common ancestry among these animals. Make sure to state what they all have in common.

Read the following passage, then continue on to complete questions 4 through 6.

Developmental homologies can be observed by studying similarities in embryos’ formation. For this station, you will analyze common features of early chordate development, then evaluate these similarities as evidence of common ancestry. Chordates, from the phylum Chordata, are animals that are mostly vertebrates (this phylum does include some related invertebrates). Humans, whales, fish, and squirrels are all chordates.

All chordates share four anatomical structures that appear during specific embryonic developmental stages. Below is a diagram of a very early embryonic chordate. This illustration shows the different parts that all chordate embryos share at some point in their development. The fact that all chordate embryos share these features at some point is one of the major pieces of evidence that points to the common ancestry of all chordates.

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4. What are developmental homologies, and how are they studied?

5. What is a chordate, and what do all chordates have in common at some stage of development? Explain.

6. What is a notochord, and where is it found?

7 Week 6- Day 4 STEMscopedia Today's Assignment 1) Read STEMscopedia and complete review questions

STEMscopedia Evidence of Common Ancestry Review Questions Reviewing Key Terms Use each of the following terms in a separate sentence.

1. Common ancestry 3. A branched diagram showing 2. Homology relationships between organisms is 3. Fossil record a(n)– 4. Vestigial structures a. amino acid sequence. b. fossil record. Use the correct key term to complete each of c. cladogram. the following sentences. d. DNA sequence.

Making Connections 1. ______are structures that no longer have a use in an organism. 1. Explain the connections between each 2. Structures that are similar and suggest line of evidence and the claim of common ancestry are ______. common ancestry and biological 3. ______sequencing shows the evolution. genetic homologies between organisms.

Reviewing Main Ideas 2. Describe four lines of evidence that suggest common ancestry. 1. Older fossils appear in rock layers– a. below new fossils 3. How can vestigial structures also be b. above new fossils considered evidence for evolution? c. in the same layer as new fossils d. that also have new fossils Open-Ended Response

2. Which of the following is not a line of 1. How does the fossil record suggest evidence supported by empirical common ancestry? evidence? a. How similar DNA is between 2. What is an example of a vestigial organisms structure in humans? b. Length of the organism's life c. Where fossils are found 3. Describe the importance of amino acid d. How similar the organisms were sequencing in the study of evolution. as embryos