Speciation Flashcards
(42 cards)
What is a biological species?
A biological species is a population in nature where where individuals breed to produce fertile offspring.
What is microevolution?
Microevolution is the change in allele frequency’s and the phenotypic traits within a population and over a period of time.
What might cause microevolution?
Mutations, genetic drift, non random mating, natural selection.
What is speciation?
Speciation is the formation of species from already existing species.
What is another name for speciation?
Macroevolution
What is a biological species?
It includes all members of a populations that can breed under natural conditions.
Populations of different species do not exchange genetic information, why is this?
They have different gene pools
Explain, what is a reproductive isolating mechanism?
It is any biological factor that prevents two populations from interbreeding when they live in the same population.
What are the two types of reproductive isolating mechanisms?
Pre-zygotic and post-zygotic.
Pre-zygotic barriers means…
It prevents fertilization and the formation of zygotic.
What are examples of pre-zygotic barriers?
Behavioural isolations, temporal isolation, ecological/habitat isolation, mechanical isolation, and gametic isolation.
Describe behavioural isolation, include an example.
Different species use different mating clues to find and attract a mate. Example: male frogs have unique calls that attract only females of their own species.
Describe temporal isolation, provide an example.
Different species may breed at different times of the year. Example: one species may reproduce in the spring, but the other species may reproduce in the summer.
Describe ecological isolation, provide an example.
Very similar species may occupy different habitats within a region. Example: a bird that lives at high elevations, and a bird that lives at a low elevation.
Describe mechanical isolation.
Differences in morphological features may make two species incompatible.
Describe gametic isolation.
Male gametes might not be able to recognize and fertilize an egg of a different species.
Post-zygotic barriers means…
It can prevent an already fertilized egg from growing into viable and reproducing adults.
What are the three post-zygotic barriers called?
Zygotic mortality, hybrid inviability, and hybrid infertility.
Describe zygotic mortality, provide example.
Mating and fertilization are possible but genetic differences result in zygote that is unable to develop properly. Example: some sheep and goat are able to mate but zygote is not viable.
Describe hybrid inviability, provide example.
A hybrid individual develops but either dies before birth, or if born alive cannot survive to maturity. Example: tigers and leopards are able to cross but zygote develops and results in a still born.
Describe hybrid infertility, provide example.
Hybrid offspring remains healthy and are viable but sterile.
What are the two types of speciation in which gene flow is disrupted in a population?
Allopatric Speciation and Sympatric Speciation
What is allopatric speciation?
New species will form when a single species is separated into two geographically isolated populations.
How does allopatric speciation work in terms of disrupting gene flow in a population?
A physical barrier divides one population into two or more. From there these groups can no longer exchange genetic information. Over generations these separated populations will grow more and more unalike.
