Download Bio - Evolution Do Ya Know ANSWER KEY

Unit 6 - Evolution
1. The 3 theories of evolution discussed in class (Lamarck, teleology, Darwin)? How does
each theory describe the development of species over time?
Lamarck – believed that organisms could acquire certain characteristics and then pass
them down to offspring
Teleology – belief that evolution has a pre-determined result
Darwin – some organisms are more fit than others, so they will have more success
surviving and reproducing. These traits are then passed on more often, changing the
make-up of the population over many generations.
2. What an acquired trait is? How do they relate to Lamarck’s theory of evolution?
Acquired trait – trait that is obtained through experience or behavior. Lamarck believed
that these traits could be passed down to offspring.
3. The main points of Darwin’s theory of evolution by natural selection? Why does natural
selection affect an entire population and not an individual?
Variation exists in all populations, and some individuals are better suited to survive and
reproduce in the environment. Those that are able to reproduce more successfully will
pass these traits to the next generation, and over time the genetic make-up of the
population changes.
Individuals cannot evolve, because individuals cannot spontaneously change their
genetic make-up. The population changes over time as some characteristics become
more or less common over time.
4. What the term “fitness” means? How does it relate to Darwin’s theory?
Fitness – the ability to survive and reproduce in a given environment. Darwin argued that
not all individuals in a population were equally fit, and some would have more success
surviving and reproducing.
5. What the term “adapt” means (in terms of evolution)?
Adapt – when a population as a whole changes genetically over time
6. What the 5 mechanisms for evolution are? How do these mechanisms change the allele
frequency of a population?
Mutation – random changes to an organism’s DNA, creates new alleles
Migration – movement into/out of a population, organisms take their genes with them,
either adding to or taking away from the genetic diversity of the population
Genetic Drift – random changes to the genetic make-up of a population caused by
changes in size. Either some event drastically reduces the number of individuals
(bottleneck) or individual break off to colonize a new area (founder effect)
Non-random mating – not all individuals in the population have an equal chance of
reproducing
Natural Selection – certain individuals are more fit to survive and reproduce in the
environment
7. What a gene pool is? What are allele frequencies? How do these terms relate to one
another?
Gene pool – the total number of alleles in a population
Allele frequency – how often a particular allele is seen in a population
Part/whole relationship – gene pool is all of the alleles, allele frequency is what
percentage of the whole is made up of one particular allele
8. The difference between immigration and emigration?
Immigration – movement into a population
Emigration – movement out of a population
9. What genetic drift is (think about the beetle example from class)?
Genetic drift – changes in allele frequency due to population size
10. The three types of natural selection? Be able to identify the graph associated with each.
Stabilizing selection – when the average form of a trait is favored (ex: height in humans)
– graph looks like more slender bell curve
Directional selection – when one extreme of a trait is favored (ex: dark skin in equatorial
areas) – graph looks like a bell curve skewed in one direction
Disruptive selection – when both extremes of a trait are favored (least common type of
selection, if coupled with geographical isolation, can result in new species) – graph high
on either side, low in the middle
11. The 3 types of evidence for evolution discussed in class (embryology, anatomy, amino
acid/DNA sequences)? How do these pieces of evidence support the theory of evolution
and/or show relationships between organisms?
Embryology – study of early development. Closely related species show many similarities
in structure, appearance, and also sequence of development
Anatomy – study of body structures. Closely related species may show many similarities
in internal structure, even if the external appearance is very different.
Amino Acid/DNA sequences – Closely related species show many similar/identical
sequences. Shows connection between different living things at the molecular level.
12. The difference between homologous and analogous structures? What do these
structures show us? Be able to name examples of each.
Homologous Structure – Internal structure is similar, external appearance/function is
different. Shows connection between organisms because internal anatomy changes at a
slower rate. Ex: forelimbs of different mammals have identical bone arrangement, but
serve very different purposes – human arm, dog front leg, dolphin flipper
Analogous Structure – External appearance/function is similar, but internal anatomy is
completely different. Shows that organisms are not closely related/come from different
ancestry. Ex: bird wing and butterfly wing
13. What a vestigial structure is? What does it show us? Be able to name an example.
Vestigial structure – structure that is still present, but not used. Shows a connection
between organisms with a working version of the structure and those with the vestigial
version. Ex: human tailbone
14. The difference between co-evolution, convergent evolution, and divergent evolution? Be
able to describe examples of each.
Co-evolution – two organisms change in response to interactions with one another (often
seen in predator/prey relationships)
Convergent evolution – organisms with different ancestry develop similar characteristics
because of similar pressures from the environment (Ex: dolphins and sharks – similar
coloration, body shape, but dolphins are mammals and sharks are fish)
Divergent evolution – organisms with a similar ancestry develop different characteristics
because of different demands from the environment (Ex: human population originated in
Africa, but different phenotypes are seen in different geographical areas because of
different environments)