Evolution Test Review

1. Give a definition for evolution. Why do living things need to evolve?

• Definition: species change over time

• As the environment changes, living things need to survive, so they must change as time goes on

2. How are fossils dated? • Radiometric/ Radiocarbon Dating: measures the

amount of radioactive isotopes in a fossil to determine its age– Pro: can give you the exact age of a fossil– Con: can’t be used on really old fossils because the

radioactivity goes away with time• Relative Dating: compares the age of a fossil to

other fossils found in the same rock layer– Pro: can be used to give you an estimated age of

really old fossils– Con: rock layers can be shifted by earthquakes or

mudslides and this can give an inaccurate estimate

3. How can we get evidence for evolution from the fossil record?

• The fossil record shows us how living things have changed their forms over time

4. What are homologous structures? Give an example. How do they

provide evidence for evolution?

• Similar structures with different functions• Example: a human’s arm and a bat’s wing• Evidence: they show that there was a

common ancestor

5. What are vestigial structures? Give an example. How do they provide

evidence for evolution?

• Structures that no longer serve a purpose but had a purpose in an ancestor

• Example: Tailbone in humans; wings on flightless birds

• Evidence: show how things change over time

6. How does embryology (study of embryos/development) provide

evidence for evolution?

• Similarities among embryos show a common ancestor

• Also show how things have changed over time (ex – human embryos have gill slits and tails as embryos that go away during development)

7. What molecular evidence can be used to support the theory of

evolution? Why does it support the theory?

• Similar DNA sequences and proteins• The more close the DNA sequences and

proteins are, it is thought that the more closely related the two species will be

8. How does biogeography provide evidence for evolution?

• It shows that island species have a lot of similarities to animals on the closest mainland

• It shows how species have adapted for the climate that they live in

9. Explain Charles Darwin’s discoveries (finches and tortoises).

• Finches: – Darwin noticed that where there were nuts for

food, the finches had short, hard beaks– Where there was fruit and insects for food, the

finches had long, thin beaks• Tortoises:– Darwin noticed that where there was low

vegetation, the tortoises had short legs and necks– where there was high vegetation, the tortoises

had long legs and necks

10. What are adaptations? Give an example of an adaptation

• Adaptation: a beneficial change that allows an organism/species to survive

• Example: thick fur on a rabbit that lives in the arctic

11. What 3 things can we learn by studying cladograms?

• Cladograms show:– Shared traits– The order the traits appeared in– Probable relationships

12. How do you read a cladogram?

• Reads from the bottom up– Oldest/most common trait at the bottom– Newest/least common trait at the top

• Each organism on the cladogram has all the traits below it

13. What are Linnaeus’ 7 different taxonomic groups from largest to

smallest? What can classifying things tell you about evolution?

• Kingdom, Phylum, Class, Order, Family, Genus, Species

• Classification can tell you how closely related two species are and how recently they shared a common ancestor – the more of the above groupings they have in common, the more closely related they are

14. How do you read a dichotomous key?

• Select an organism/specimen to identify• Begin reading the key at line 1• Follow directions on key until you are able to

identify your organism/specimen

15. Describe survival of the fittest.

• The best adapted to the environment will survive and leave offspring behind to continue the species

• Example: the fastest running prey will be able to avoid predators and survive better than slower prey

16. What is the purpose of sexual selection?

• Gives males traits to attract the best females to mate with

• This allows the species to better survive

17. Describe extinction (include background and mass). Why do

species become extinct?• Background: happens over longer time

periods at a slow rate• Mass: happens suddenly and drastically

(wipes out lots of species on a global level)• Species become extinct because they lack the

variations needed to survive

18. Describe genetic drift. Include the bottleneck effect and founder effect.

• Genetic drift: changes in the alleles of a population due to chance

• Bottleneck effect: occurs when a “bottleneck event” (ex – natural disaster) drastically reduces the population so that it no longer resembles the original population

• Founder effect: occurs when part of a populations colonizes a new area and most likely evolves into a new species

19. What is gene flow?

• Movement of alleles between populations– Example: migration

20. What does it mean to be biologically fit?

• It means that the individuals are able to survive and reproduce

21. What are variations? Give an example.

• Differences in a population• Example: different beak types in finches

22. What is a gene pool?

• All the genes available to a population

23. What are allele frequencies?

• How often certain alleles are seen in a population

• They can tell you which genes better help a population survive (a more common gene would be thought to be more beneficial)

24. What is natural selection?

• Organisms will inherit beneficial adaptations that will help them survive and leave behind more offspring than other individuals

25. What happened in the Wooly Worm lab? Why was it easier to find certain colors over others?

• “worms” of different colors were collected during different timed intervals

• Certain colors stood out so it was easier to see them and collect them than it was the colors that could camouflage themselves against the colors of the room

26. Describe directional, stabilizing, and disruptive selection. Give examples.

• Directional: favors phenotype at one extreme– Example: bacteria that are resistant to antibiotics will survive and

shift the population to all (mostly) have that same trait• Stabilizing: favors the intermediate phenotype– Example: gall flies lay their eggs in plants and that creates a “gall”

in the plant – the medium sized galls are left alone while the small galls are destroyed by wasps and the large galls are destroyed by woodpeckers

• Disruptive: favors both extreme phenotypes– Example: bright blue (dominant trait) male buntings (birds) will

attack and kill blue-brown (intermediate pheno.) males and leave the brown (recessive) males alone

27. How do you correctly type and handwrite a scientific name? Give an

example.• Two words, first letter of the first word capitalized– Typed: in italics– Handwritten: underlined

• Example: Homo sapiensHomo sapiens (pretend this is handwriting)