On PowerPoint
1. Theories of Evolution
2. Evidences of Evolution
What is evolution? Slow gradual change in a species over time
Micro: mutations  variation within a population
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Change in the frequency of alleles – amount of times a gene appears in a population
Beneficial/ harmful/ neutral
Macro: speciation
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Works most directly on populations (not species, never an individual)
Allopatric speciation - geographic barrier – geographic isolating mechanism
Sympatric speciation – no geographic barrier – habitat/ecological isolation/ behavioural
isolation
Patterns:
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Adaptive radiation – low competition, many resources
Divergent evolution – 2 species evolved away from each other
Convergent – 2 species evolved towards each other
Coevolution – 2 species evolve together, occurs most in symbiotic relationships
What defines a species? Biological species concept: a species is one that CAN produce viable and fertile
offspring between individuals
How does a new species form?
1.
2.
3.
4.
Selection Pressure – e.g. lack of food, hiding from predators
Mutation/ Variation within a population
Selective Advantage
Reproductive isolation from the original population
Without 1: population will survive, no need to change
Without 2: population won’t be able to adapt
Without 3: the entire population will die
Without 4: the entire population will evolve together, speciation might not occur
Without 1 & 3: genetic drift – bottleneck effect, founder effect
What’s the difference between natural/ artificial selection? Intervention by humans
How does EXTINCTION occur? No more of a certain species.
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Major catastrophic event not required for extinction to occur (e.g. low reproductive success in
pandas)
Other concepts/ key terms:
Selection patterns for polygenic traits – disruptive selection, stabilizing, directional
Adaptation/ Survival of the fittest – population not an individual
Gene Pool / Allele Frequency Duplication Mutations
Polygenic Traits – traits that are coded by more than one gene. (poly = many, genic = genes)
Review pg. 382 # 1, 6, 7a, 8b, 17-19ftf, 21t, 22f, 28t, 32ii/i/iv/iii, 33iv/iii/ii/v/i, 35iii/ii/I, 36ii/i/iii, 38, 39,
43-45, 47, 49, 50, 55, 57, 58, 62, 63, 68, 69, 70, 75, 96, 98, 103, 108
The difference between natural and artificial selection (7.1)
1. Artificial selection
(a) reduces the genetic diversity of a population
(b) increases the genetic diversity of a population
(c) reduces the number of harmful mutations
(d) rapidly produces new species (7.1)
Related Unit Test Question:
What is evolution? (8.1)
6. Biologists often describe evolution as a change in
(a) the number of alleles in a population
(b) the frequency of alleles in population
(c) mutation rate
(d) the immutability of nature (8.1)
Related Unit Test Questions:
____
2. The unit upon which evolution acts most directly is a(n):
a. individual
b. population
c. species
d. race
The Modern Theory of Evolution
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5. Which statement is true about the modern theory of evolution?
a. Harmful mutations have no immediate influence on the success of an individual.
b. The modern synthesis of evolutionary biology combined Darwin’s theory of evolution by
natural selection with the science of plate tectonics.
c. Pseudogenes provide compelling evidence for evolution.
d. Neutral mutations are favoured by natural selection.
____
7. Since pseudogenes no longer serve a useful purpose in a species, they can be compared to
a. homologous features
b. analogous features
c. vestigial features
d. none of the above