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Unit 8 Study Guide | Test Date: _________________________
1. What is biological evolution? Change in gene frequency in a
population over time. It has shaped changes in organisms
from their earliest beginnings to now.
2. Compare microevolution vs. macroevolution. How are they
different? Microevolution is evolution of a single
population (caused by genetic variability), whereas
macroevolution is the evolution of an entire species
(because of the environment).
3. What is a common ancestor? An ancestor that is shared by
two similar species.
4. Biological evolution occurs through natural selection. What is
natural selection? Survival of the fittest – whoever is most
fit to survive in the environment will live and make more
babies.
5. What are the four principles of natural selection?
Overproduction of offspring, variation, adaptation, and
descent with modification.
6. How does overproduction of offspring influenced by natural
selection? The more offspring an organism has, the more
likely some will survive to reproduce.
7. How does variation influenced by natural selection? Good
genes and physical characteristics will be passed on while
bad ones die out.
8. What is adaptation? Developing traits that make an
organism more fit to survive in its environment. Ex:
camouflage
9. How does adaptation influenced by natural selection? Natural
selection favors good adaptations – those that help the
organism survive. Bad adaptations will lead to the
organism’s death.
10. FYI: All life that exists or has existed on earth share the
same nucleic acids and the same proteins.
11. What are the two types of reproduction? Sexual and
asexual reproduction
12. How does genetic variability occur in sexual
reproduction? Crossing over, gene shuffling, mutations
13. How does genetic variability occur in asexual
reproduction? Only mutations
14. Contrast sexual and asexual reproduction. How are they
different? Sexual reproduction requires two parents,
meiosis to make gametes, lower reproduction rate, lower
offspring produced at a time, and offspring that are
genetically different from parents and each other. Asexual
requires only one parent, mitosis to reproduce, higher rate,
higher offspring, genetically identical offspring.
15. What is a species? A group of similar organisms that
can interbreed and produce fertile offspring.
16. What is a gene pool? The collection of all of the genes in
a population.
17. How does diversity affect natural selection or evolution?
The more diverse a population is, the more likely that
some will survive via natural selection. Those survivors
will shape the new population – evolution.
18. Genetic variability leads to microevolution. What are the
5 factors that influence genetic variability in a population?
Describe them. Genetic drift (small population, random
change in alleles over time), gene flow (migration),
mutation (change in DNA), nonrandom mating (sexual
selection), natural selection (survival of the fittest)
19. When there is no change in the allele frequencies within a
species, the population is in genetic equilibrium. What is
another name for this? Hardy-Weinberg principle
20. What are the 5 requirements of genetic equilibrium, or
Hardy-Weinberg principle? Large population with no
genetic drift, no gene flow, no mutation, random mating,
no natural selection
21. What is speciation? Formation of a new species
22. What causes speciation? What are some examples of
environmental factors that affect evolution? Speciation is
caused by members of a population becoming isolated,
preventing the new population from mating with the
original population. Environmental factors that affect
evolution include climate change, catastrophic events, and
continental drift.
23. What are some patterns of macroevolution caused by the
environment? Describe each. Convergent evolution (species
become more similar due to similar habitats), divergent
evolution (one species branches into two; also called
adaptive radiation or speciation), coevolution (two
organisms that rely on each other to survive evolve in
response to each other)
24. What are analogous structures? Created by convergent
evolution; structures that are similar in function but not in
structure (body shapes of sharks and dolphins, wings of
birds, bats, and bugs)
25. What is the difference between gradual and mass
extinction? Gradual extinction occurs slowly, mass
extinction is caused by one large event that affects many
species.
26. What four fields of study have given us evidence for
evolution? Anatomy, biochemistry, embryology,
paleontology
27. What is anatomy? Study of structures of organisms
28. What are homologous structures? Generated by
divergent evolution; similar structures as a result of
common ancestry, like the forelimbs (arms) of humans,
cats, horses, birds, whales, etc. May not have the same
function.
29. What are vestigial organs? Organs that are no longer
useful to the current organism, but were to the ancient
organism. Example: human appendix and tailbone, ostrich
wings, etc.
30. What is embryology? Study of the development of
embryos
31. Why is embryology helpful for studying evolutionary
history? Species that are more similar to each other have
more similar stages of development
32. What is biochemistry? All of the chemical reactions that
occur in living things
33. What molecule do we usually compare in organisms to
trace evolutionary history? DNA and proteins
34. What is paleontology? Study of prehistoric life – fossils
35. What do fossils show us? Similarities between ancient
and current species
36. What is phylogeny? Evolutionary history
37. Can we get a good picture of evolutionary history from
one piece of evidence? Why or why not? NO – there’s not a
large enough sample size. The more evidence you have, the
more reliable your data is.
38. What are phylogenetic trees? Diagrams that help show
evolutionary relationships between organisms through
time.
39. What can phylogenetic trees tell us? Common ancestry,
extinction, speciation, etc.
40. What are cladograms? A type of phylogenetic tree that
isn’t very specific – it shows basic relationships based on a
few traits rather than all traits.
41. What are the three domains of life? Bacteria, Archaea,
and Eukarya
42. What are the six kingdoms of life? Eubacteria (Domain
Bacteria), Archaebacteria (Domain Archaea), Protista,
Animalia, Plantae, Fungi (all Domain Eukarya)