Download Evolution Review answers

Evolution Review
1. What two scientists first proposed that the Earth was much older than we initially
thought? What evidence did they use to make this determination?
Thomas Hutton and Charles Lyell. They looked at the stratified nature of certain
rocks. Each layer represented a very long period of time.
2. What prediction did Malthus make in his book Essay on the Principle of
Population? How did this influence Darwin?
That the human population will increase to the point that there will be insufficient
food and resources for everyone. Class struggle would result. Darwin saw this
in nature and called it the “struggle for existence”.
3. Although Lamarck was not initially a follower of evolution, he eventually changed
his mind. Why?
He saw fossils of organisms which were clearly not on Earth anymore. They
either went extinct or evolved into something new. Lamarck thought it was
evolution.
4. Describe Lamarck’s theory on the mechanism of evolution.
Use and disuse – organisms develop or lose organs as they use or fail to use
them.
Inheritance of acquired traits – these changes are passed down to future
generations.
5. Describe two of the three key points Cuvier made against Lamarck’s view of
evolution.
Great chain of being is false – everything is too complex to have a unique
ancestor
Extinction is a reality – Earth has had more than one mass extinction event
Correlation of parts – a change in an organism makes it less able to survive as it
has be perfected adapted up to that point
6. What is catastrophic geology?
The overall landscape of the Earth is marked with large events (catastrophes)
that very aggressively change its look.
7. Discuss observations that Darwin made while on the HMS Beagle that influenced
his view on evolution.
Fossils of extinct species that look very similar to ones alive today. Minor
variation of unique species in similar environments (variation makes them better
suited to their environment. Struggle for existence in nature.
8. Why did Darwin wait so long to publish his work?
He felt his theories needed more evidence that clearly showed his proposed
mechanism.
9. What mode of evolution did Darwin develop while waiting to release his work?
How was it different than views of evolution at the time?
Speciation. Darwin proposed that different species have a common ancestor. If
you go far enough back, you will find a common ancestor for all species.
10. What sort of evidence did Darwin have at his disposal that supported natural
selection?
Fossil record, homologous structures, comparative embryology, etc.
11. What did Alfred Wallace do that pushed Darwin to release his books?
He developed a theory shockingly similar to Darwin’s.
12. How does punctuated equilibrium differ from Darwin’s ideas?
Darwin thought evolution was always slow and gradual. Sometimes it might be
very aggressive and quick.
13. How did Darwin respond to the criticism of non-adaptive traits?
He proposed sexual selection in some cases.
14. Outline some of the data that has arisen over the past few years that would have
been beneficial to Darwin’s ideas.
DNA and its control.
15. Describe how comparative embryology helps explain both homologous structures
and vestigial structures.
Many embryos from different species look extremely similar. Different looking
organs (arms, wings, fins) all stem from the same set of cells in the embryo.
Vestigial structures may be lost to a certain species, but its remnants may be left
behind in the embryo.
16. Explain the Hardy-Weinberg requirements for genetic stability.
Large population size
No net mutations
Random mating
No natural selection
Isolation from other populations
17. What is the difference (if any) between microevolution and macroevolution?
Merely the time frame. Microevolution is the shift in allele frequency in a
population. The selective pressures that brought about this shift could lead to
new species given enough time.
18. 1 in 5000 students are affected by the condition examus nonstudius, a rare
recessive genetic condition. What is the probability you are a carrier?
2.78%
19. If 77% of alleles in a population are estimated to be dominant for a given
condition, what percentage of a population would you expect to be homozygous
dominant? What about heterozygous?
Homozygous dominant – 59.3%
Heterozygous – 35.4%
20. Describe the three variations on natural selection.
Stabilizing selection – the most common group is selected for. The extremes are
reduced in number.
Directional – one extreme is selected for. The population shifts in their direction.
Diversifying – two or more extremes are selected for. The population begins to
split into two or more unique species.
21. How could two species, separated by both time and location, evolve the same
structures?
With similar selective pressures, the overall anatomy and physiology of two
groups could yield very similar structures.