Studied by 48 peopleHow can you relate the Rock Pocket Mouse Activity to what we have studied in this chapter?
Because of how genes looked in genetic evolution & natural selection in a real life scenario. This also gives a realistic idea of gene shuffling between parents & their offspring.
Why does sexual reproduction make an organism more advantageous than those that do not?
An organisms' genes will live on to be more present in the population & offers more variation in the population.
Can you give any examples of a sexual selection process that humans would exhibit?
Shown in personal & stereotypical preferences in a partner. For example, a woman avoiding having sex with short men
Why (or why not) do humans demonstrate random mating?
They do not because we (generally) choose who we have sex with, versus having sex with whoever.
Why did Darwin have trouble with explaining the traits that are used for sexual attraction & natural selection?
In some cases those traits made one less suited to their environment but more likely to get a mate, which didn't make sense to him.
Why is it that we say you can observe natural selection occurring in the environment, but most likely never see evolution take place?
Natural selection happens in less than a lifetime due to dramatic changes in an environment. Evolution takes multiple lifetimes to occur due to the entire population slowly showing changes in traits & you also can't see the "moment" organisms in a population stop mating & reproducing
List some examples of things that could cause genetic drift to occur.
migration to a new area (population split up randomly), blizzards, severe droughts, volcanoes, continental drift, hurricanes, earthquakes
What type of natural selection has occurred here?
disruptive selection
Which phenotypes are selected against?
the average ones are now selected against
Which phenotypes have higher fitness?
the ones that used to be less average (the dips) that are now peaks/the average
If natural selection continues this way, what may eventually happen to the population?
the organisms at either end of the curve may split into two different species
Any change in the relative frequency of alleles in a population
evolution (modern synthesis [this is not interchangeable with evolution, just goes along with it])
A gene pool consists of all the genes in a(n)
population
The main sources of genetic variation are gene shuffling and
mutation
A random change in allele frequency is called
genetic drift
When birds cannot interbreed because they have different mating songs, they are characterized by _______ isolation
behavioral
A situation in which allele frequencies change as a result of the migration of a small subgroup of a population is known as the
Founder Effect
Two related species that live in the same area but mate during different seasons are separated by ______ isolation
temporal
When are two species said to be reproductively isolated?
once they are separated AKA once they stop mating & reproducing & having fertile offspring
Describe geographic isolation
populations are separated physically (land-wise), causing two separate gene pools to form & natural selection to work differently
Describe behavioral isolation
two populations are capable of reproducing but don't (sexual selection)
Describe temporal isolation
two or more species reproduce at different times - "Sympatric Speciation"
Give a number (1 = first through 6 = last) to tell when changes in the gene pool occurred in the speciation of the Galápagos
3
Give a number (1 = first through 6 = last) to tell when continued evolution occurred in the speciation of the Galápagos
6
Give a number (1 = first through 6 = last) to tell when the founders arrival occurred in the speciation of the Galápagos
1
Give a number (1 = first through 6 = last) to tell when reproductive isolation occurred in the speciation of the Galápagos
4
Give a number (1 = first through 6 = last) to tell when the separation of populations occurred in the speciation of the Galápagos
2
Give a number (1 = first through 6 = last) to tell when ecological competition occurred in the speciation of the Galápagos
5
Describe a situation that would result in the sudden geographic isolation of a few members of a population.
a human travels to where a group of chipmunks live, and take a small portion of them back to where the human originally resided (ie. Ohio to Maine)
Suggest one reason that natural selection on the Galápagos Islands produced species that were quite different from the ancestor species on the mainland.
environments on the islands were different from that on the mainland so the populations that went to said islands ended up evolving over time, causing them to be better suited to their environments, making them slightly to vastly different from their original population (due to slightly different environments)
What are the five conditions that need to be met to reach genetic equilibrium?
Random mating, LARGE population, no migration, no mutations, no natural selection
Describe the first condition needed to be met to reach genetic equilibrium: Random mating.
each individual has an equal chance of passing on genes
Describe the second condition needed to be met to reach genetic equilibrium: LARGE population.
genetic drift has less effect on large populations/laws of probability are easy to maintain
Describe the third condition needed to be met to reach genetic equilibrium: no migration amongst the population.
gene pool must be kept together & separate from other gene pools
Describe the fourth condition needed to be met to reach genetic equilibrium: no mutations.
these cause new alleles, changing allele frequencies
Describe the fifth condition needed to be met to reach genetic equilibrium: no natural selection takes place.
all genes must have an equal chance at survival; no selective pressure
Describe sex in the animal world.
mainly done for the purpose of reproducing, aggressive in competition, uses monogamy to ensure that one will always have a mate to reproduce with.
Describe sex in the human world.
mainly done for the purpose of pleasure, less aggressive & more deceitful in competition, monogamy for romantic love instead of reproduction
What determines the role of male or female in all species that reproduce sexually?
whatever is most beneficial to the population, roles are not unchanging.
When looking at the types of selection that occur to traits in populations that are not single-gene traits (polygenic), which is usually the way selection occurs in nature? Explain why.
stabilizing selection - generally remains the same, the middle part of the curve just gets steeper; middle part is the average; this change in the environment (and in graph) is less dramatic than the other two, so it happens more often
In the Rock Pocket mouse video, what was the significance of studying dark mice from DIFFERENT lava flow areas?
to see how the two different mice populations have two different mutations but similar/same coloring b/c of natural selection
Define emigration.
movement out of a population
Define immigration.
movement into a population
Define selective pressure.
effects of natural selection on a gene or a mutation of a gene
Define evolutionary fitness
an organism's success in passing genes to the next generation
Define evolutionary adaptation
any genetically controlled anatomical, physiological, or behavioral trait that increases as organism's ability to pass its gene
Define modern synthesis
evolution is any change in relative frequency of alleles in a population
what are dominant & recessive classified as
single-gene traits
Define directional selection
individuals at one end of the curve have higher fitness than individuals in the middle or at the other end; causes the range of variations to shift due to some organisms fail to survive & reproduce, while others succeed
Define stabilizing selection
individuals near the center of the curve have higher fitness than individuals at either end of the curve; center of the curve remains where it is but it gets narrower or steeper; organisms become more like the average
Define disruptive selection
Individuals at the upper & lower ends of the curve have higher fitness levels than individuals near the middle; intermediate type (average) is selected against; can cause a single curve to split into 2
Define genetic drift
random change in allele frequency
What is temporal isolation?
when two or more species reproduce at different times (have different mating seasons)
Why don't humans exhibit temporal isolation?
humans don't have designated mating times
How are the ideas of sexual selection and natural selection similar?
both determine the fitness of an organism, affect the relative frequency of a population, and are based on genetics (specifically phenotypes)
How are the ideas of sexual selection and natural selection different?
natural selection is affected by the environment/not chosen by an organism, sexual selection is affected by individual organisms/chosen by an organism (choice of mate), characteristics bad for an environment (natural selection) can be good for sexual selection (mating)
What is the difference in the role of female sex cell and the role of male sex cell in sexually reproducing organisms?
female sex cell is more costly & scarce, males produce so much sperm, no reason to be picky. more about competition, in an attempt to have as much reproduction as possible
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