Speciation & Comparative Anatomy

Warm-Up: Using the picture to the left, state Darwin’s theory of evolution by natural selection 3 answers: Justify WHOSE answer is the most accurate

Daily Goals and Objective What: Describe comparative anatomy. 2.9b RWC: 3.2 f/g How: Given 1 MC and using a diagram, support the theory of evolution with the concept of comparative anatomy. (4/5) Why: Evidence for evolution! How are you similar to a bat?!

Biological Species Concept A group of organisms that can interbreed and produce viable, fertile offspring Photo Credit of Galápagos Marine Iguanas: Putneymark, 2008, Wikimedia Commons

Biological Species Concept Assumes Common characteristics Genetically compatible Interbreed under natural conditions Sexual Reproduction Photo Credit of Iguana iguana: Ianare, 2007, Wikimedia Commons

Speciation Allopatric speciation Sympatric speciation Process of species formation Two main mechanisms: Allopatric speciation Sympatric speciation

Allopatric Speciation Geographic separation  Genetic exchange Populations become genetically different Reproductive isolation

Sympatric Speciation Populations not geographically separated Can be due to rapid genetic changes: Alter morphology Alter behavior Alter habitat preferences

Example: Sympatric Speciation Euhadra snails Mutation in one gene  Shell spirals in opposite direction Instant mechanical isolation  Two species

Adaptive Radiation A common ancestor  Many new species Relatively rapid Common in island chains Isolated Numerous habitats & resources Map Credit: M. Minderhoud, 2006, Wikimedia Commons

Galápagos Finches Ancestral finch from South America  Several finch species Different diets Different beak shapes Different beak sizes

Galápagos Finches

In Pairs….. Do you have similar anatomical features with a bat, an alligator and a penguin. Yes or No? Justify your answer TRUE!!!: They all evolved from a common ancestor and they do share similar traits – for example the forelimbs!

Comparative Anatomy 1. Homologous Structures: structures similar in location, structure or appearance but not always function The structures have a common origin (ancestor) Recent common ancestor or A and B

Which of the following best describes homologous structures 1. Structures that are different in appearance or location but always have the same function 2. Structures that are different in appearance or location and different in function 3. Structures that are the same in appearance or location and have the same appearance 4. Structures that are the same in appearance or location but can have different functions WHAT MAKES THE OTHER PARTS WRONG!!

Explain how Elvis Presley look alikes are NOT an example of homology

Do the two organisms that are circled demonstrate comparative anatomy?

Check In 1. Which of the following best describes comparative anatomy? A.) Structures on organisms that look don’t look the same and don’t have the same function B.) The anatomy of organisms C.) To compare the anatomy of all organisms D.) Similar structures that have a common ancestor

Use the picture below to compose a proficient (3 evidences) evidence statement to support the claim Claim: Bats, humans, whales and horses evolved from a common ancestor. Evidence: 3 pieces of evidence to show that all the organisms evolved from a common ancestor. Reasoning: Summarize how this relates to the theory of evolution.

Share with your partner: Highlight the most convincing sentence in their paragraph Grade your answer based on the exemplary below How did you grade your CER? What was 1 thing you could have added? Claim: Bats, whales, humans, and horses all evolved from a common ancestor. Evidence: One piece of evidence to support the claim is that humerous, radius, ulna, and carpals are all located in the same area in all species. Reasoning: Due to the fact that all these species share similar bone structure supports the idea that they all evolved from a common ancestor. http://evolution.berkeley.edu/evolibrary/search/search_lessons_start.php

DOL Using the picture below: 1. Would the tail of a dolphin and an ambulocetus be an example of comparative anatomy – Justify your answer -2 points 2. Describe how comparative anatomy can be used as evidence for evolution. – 2 points

Challenge Question A moth and a bird both have wings to fly. A moth is an insect while a bat is a mammal. Would the wings of a moth and a bird be considered homologous? Justify your answer.