1. Evolution Test Review

2. 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

3. 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

4. 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

5. 4. What are homologous structures. Give an example
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

6. 5. What are vestigial structures. Give an example
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

7. 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)

8. 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

9. 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

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

11. 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

12. 11. What 3 things can we learn by studying cladograms?
Cladograms show:
Shared traits
The order the traits appeared in
Probable relationships

13. 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

14. 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

15. 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

16. 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

17. 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

18. 17. Describe extinction (include background and mass)
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

19. 18. Describe genetic drift
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

20. 19. What is gene flow? Movement of alleles between populations
Example: migration

21. 20. What does it mean to be biologically fit?
It means that the individuals are able to survive and reproduce

22. 21. What are variations? Give an example.
Differences in a population
Example: different beak types in finches

23. 22. What is a gene pool?
All the genes available to a population

24. 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)

25. 24. What is natural selection?
Organisms will inherit beneficial adaptations that will help them survive and leave behind more offspring than other individuals

26. 25. What happened in the Wooly Worm lab
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

27. 26. Describe directional, stabilizing, and disruptive selection
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

28. 27. How do you correctly type and handwrite a scientific name
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 sapiens
Homo sapiens (pretend this is handwriting) 