Understanding Evolution: Homology and Analogy KEY

http://evolution.berkeley.edu/evolibrary/ .........................Go to Similarities and differences: Understanding homology and analogy

1. a) In the image, which pair represents an analogy and which a homology?
b) Define homology: traits inherited from a common ancestor
c) Define analogy: similarity not due to common ancestor

2. What is a tetrapod? animals with four legs

3. What are the six bones found in all tetrapod legs? radius, humerus, ulna, carpals, metacarpals, phalanges

4. Identify these limbs (to what animal do they belong)? human, bird, whale, lizard

5. What did the common ancestor of all modern tetrapods look like? like a lizard

6. Side Trip: "not just anatomy." - How are a bird and a crocodile homologous? both take care of their young

7. Similar structures that evolved independently are called _analogies____.

8. a) What is the difference between a marsupial and a placental? marsupials develop young within a pouch

b) What is Smilodon? saber toothed cat

c) What is Thylacosmilus? related to marsupials, has saber like teeth

9. Describe how two unrelated flowers could evolve to have a similar appearance? they both evolved to have a similar function, like attracting birds

10. Are similarities between sharks and dophins homologous or analogous? analogous, they evolved for the same purpose (swimming)

11. What is morphology? form and structure of an organism

12. What three criteria are used to determine whether something is a homology or analogy? structure, relationship, development

13. Fill in the blanks of the primate tree. panda, chimp, human, gorilla

14. Considering all of the evidence, are the "wings" (actually flaps of skin stretched between the legs) of sugar gliders and flying squirrels homologous or analogous structures? Explain why you would conclude this. analogous, they are adapted for flight, but they are not related to each other

15. Sidetrip: See more examples of homology and examples of analogy.

a) How are a venus fly trap and a pitcher plant homologous? both have modified leaves used to trap insects

b) What is unique about bowerbirds? males build fancy nests, or bowers

c) What does the Pax - 6 gene do? builds an eye

d) What plant gave rise to cauliflower and broccoli? wild mustard

e) The bones of the ears in mammals are homologous to what in lizards? jawbones