Evolution Quiz #2 Flashcards
What is gene flow (migration)? Give an example.
The movement of alleles as a result of migration. (Example: Grey wolves travel long distances to find mates)
What is a habitat/ecological (reproductive) isolation? Is it pre-zygotic or post-zygotic? Provide an example.
Two populations that live in the same environment, but different habitats, ∴ never encounter each other.
- Pre-zygotic
(Example: Garter snakes. Common prefers water; northwest prefers meadows)
What is adaptive radiation? Provide an example.
The evolution of an organism into a wide variety of differing types of that same organism.
(Example: Darwin’s finches)
What is natural selection?
Organisms that are better adapted to their environment are more likely to survive.
What is sympatric speciation?
When a new species forms without a physical barrier.
What is a mechanical (reproductive) isolation? Is it pre-zygotic or post-zygotic? Provide an example.
Two closely related species attempt to mate, but are unsuccessful because genitals are incompatible.
- Pre-zygotic
(Example: differing dragonfly species)
What is divergent evolution? Provide an example.
A pattern of evolution, where species that were to an ancestral species DIVERGE and become more distinct.
(Example: Wolves and differing breeds of dogs)
What is genetic drift?
Changes in an allele frequency because of random events in a population.
What is mutation? Give an example.
Any change in the DNA sequence of an organism.
(Example: Rats becoming resistant to poison)
What is the founder effect?
New populations that are formed by founders. Founders carry some, but not all, the alleles from the original population.
What is a behavioural (reproductive) isolation? Is it pre-zygotic or post-zygotic? Provide an example.
Behaviours involved in mating are so unique that they prevent mating
- Pre-zygotic
(Example: Bird calls)
What is hybrid inviability? Is it pre-zygotic or post-zygotic? Provide an example.
Genetic incompatibility stops the development of a zygote.
- Post-zygotic
(Example: if a goat and a sheep mate, an egg will be fertilized, but due to dysfunctional mitosis, the embryo dies)
What is gradualism? Is this supported by Darwin or modern research?
Gradualism suggests that evolution occurs at a slow, but constant rate.
- Supported by Darwin
What is the bottleneck effect?
When a population is quickly reduced (e.g by a natural disaster) and the surviving population only has a fraction of the alleles that the original population had.
What are the requirements for natural selections?
1) Variation in alleles
2) Not all individuals reproduce to their full potential
3) Surviving offspring pass down favourable traits
What is the criteria for speciation? (How do you know speciation has occurred?)
Members of a population change so much that they are unable to mate/breed with the original population?
What is convergent evolution? Provide an example.
A pattern of evolution where species have INDEPENDENTLY ADAPTED to similar environmental conditions. (Example: Birds, bats, butterflies; all have wings, but do not share a common ancestor)
What is a temporal (reproductive) isolation? Is it pre-zygotic or post-zygotic? Provide an example.
Two populations that live in the same environment, but mate at different times. (i.e. of year, of day, of moth)
- Pre-zygotic
(Example: Cicadas mate at different times of year)
What is hybrid breakdown? Is it pre-zygotic or post-zygotic?
Offspring are fertile, but become less fertile as generations go on.
What is a gametic (reproductive) isolation? Is it pre-zygotic or post-zygotic? Provide an example.
Gametes meet, but do not form a zygote.
- Pre-zygotic
(Example: differing species of sea urchins)
What is non-random mating (Inbreeding)? Give an example.
When closely related individuals mate. (Example: Shar-pei dog)
What is allopatric speciation?
When a new species forms because of a physical barrier.
What does post-zygotic mean?
After fertilization
What is punctuated equilibrium? Is this supported by Darwin or modern research?
Punctuated equilibrium suggests that for most of the time species evolve at a constant rate, but are interrupted by periods of divergence.
- Supported by modern research
What does pre-zygotic mean?
Before fertilization
What is hybrid infertility (sterility)? Is it pre-zygotic or post-zygotic? Provide an example.
Organisms can grow and live a full life, but are infertile.
- Post-zygotic
(Example: Mules are infertile)
What is speciation?
The formation of a new species from an existing species.
