Exam 2 Review

Define phylogenetic species concept Strengths and weaknesses?

defines a species as the smallest group of individuals that share a common ancestor strength:

Under what conditions does inbreeding have a minimal impact?

large populations

What happens when heterozygotes are favored by selection?

sickle cell anemia

What are inversions and what are some examples?

a chromosome rearrangement in which a segment of a chromosome is reversed end to end

Know polar bear example from book

are a distant species that originated from a population of brown bears -MAY BE ABLE TO TELL MORE ABOUT

Define speciation

formation of new species

Found effects relationship with genetic drift?

they're both examples of a drastic change within a population and how the genetic variation can be shifted due to the events

What is founder effects relationship with sampling error?

when a few individuals from a large population relocated to a new isolated area the can cause little gene variety which is a potential sampling error

When does hybridization result in either reinforcement or speciation?

when a hybrid offspring has lower fitness, natural selection will push for reinforcement. -whereas like in flies, hybridization in young can cause a new species entirely

Antagonists

parasites and their hosts -creates negative frequency dependent

What is an evolutionary arm's race? Why is it a race with no end?

predators and prey co-evolve adaptations for prey capture and predator avoidance due to their strong evolutionary influence on one another. -only ends with the extinction of one creature, which would ultimately lead to a lack of food supply for the other

Hardy-Weinburg Principle

principle that allele frequencies in a population will remain constant unless one or more factors cause the frequencies to change; null hypothesis

What are the problems and benefits of inbreeding?

problems: deformations can occur and can cause rare alleles to take favor -people are homozygous to the recessive genes -higher mortality, decreased fitness benefit: royalty stays within a single family

What is the concept of "use it or lose it"?

refers to having a trait that is not used anymore, and disappears or fossilizes over time -ex: vestigial traits like human tail bone, legs on snakes, whale hip bone

Why do old-world primates with full-color vision have so many fossilized genes for olfaction?

relying on olfaction after development of color vision was useless, as a result, the genes fossilized over time

What is Gene Duplication and what are some significant examples that pertain to humans?

results from unequal crossing over and is any duplication of a region of DNA -ex: prolactin, Hilton, tRNA, rRNA, globing and immunoglobulin

What is reinforcement?

results when hybrid offspring have low fitness and natural selection results in assortative mating and pre-zygotic isolation

What is the relationship between population size and mutation impact?

small populations have a higher risk for losing allelic frequency and genetic diversity -a larger population has more mutations and more genetic diversity

Morpho-species concept Strengths and weaknesses?

species designation and identification is based on this -this is the primary way fossils are assigned to species -this approach works very badly for some fungi, bacteria, and archea

What ia allopatric speciation?

the formation of new species in populations that are geographically isolated from one another -ex: beetles and wasps

What is sympatric speciation?

the formation of new species in populations that live in the same geographic are -ex: apples and hawthorns

What are evolutionary trade-offs and what are some examples?

the idea that many traits that confer a fitness advantage with respect to one aspect of the environment can also have a fitness cost relative to another ex: human big brain with small gut or human small brain with large gut

Biological species concept Strengths and weaknesses?

the idea that species are groups of actually (or potentially) interbreeding natural populations that are reproductively isolated from other such groups

What is founder effect?

the loss of allelic variation that accompanies founding of a new population from a very small number of individuals (a small sample of a much larger source population) -can cause the new populations to differ considerable from the source population -type of genetic drift

What is coefficient of inbreeding (F)?

the probability that the two alleles at any locus in an individual will be identical because of common descent. -Fpedigree by measuring the reduction in heterozygosity across loci within the genome of that individual attributable to inbreeding, or it can be estimated for a population, by measuring the reduction in heterozygosity at one or a few loci sampled for many different individuals within the population

Define sampling error and understand its interaction with genetic drift and population size

the statistical characteristics of a population are estimated from a subset or sample of the population

What is horizontal gene transfer and in what organism do you see it?

the transfer of genetic material-other than from parent to offspring-to another organism, sometimes a distantly related one, without reproduction. -once this material is added to the recipient's genome, it can be inherited by descent

What happens when homozygotes are favored by selection?

there's additive alleles

When dealing with conservation issues, what are the relationships between habitat fragmentation, population size, gene flow, inbreeding, homozygosity fitness, reproductive success, inbreeding depression, and extinction?

these can affect how to go about effectively conserving the existence of a species

What impact do mutations alone have on selection?

they create variation, which can allow for selection depending on certain ecological factors

What is meant by secondary contact?

when allopatric populations come back into contact with each other -become sympatric

What are some predator adaptations?

Mimicry, cryptic coloration, speed, acute senses

Batesian mimicry

a harmless species mimic a harmful one

What is the adaptationist program?

evolutionary biologists who do research to demonstrate adaptive traits in organisms

Are mutations usually deleterious, beneficial, or netural?

neutral

What is genetic load?

the burden imposed by the accumulation of deleterious mutations

What is heterozygote superiority?

the fitness of the heterozygote is greater than that of both homozygotes

What is inbreeding depression? know how to interpret value in figures

the negative reproductive consequences for a population associated with having a high frequency of homozygous individuals possessing harmful recessive alleles

Mullerian mimicry

two or more unpalatable species resemble each other

What is isolation by distance?

a pattern in which populations that live in close proximity are genetically more similar to each other than populations that live farther apart

What are the differences between selection and genetic drift? Under what condition will each of them be important?

genetic drift is random selection is nonrandom

What are germ-line mutations?

mutations that affect the gametes (eggs, sperm) of an individual and can be transmitted from parents to offspring. -creates the heritable genetic variation that is relevant to evolution

Symbionts

the smaller organism in a symbiotic relationship

What are some anti-predator adaptations?

-Toxins, spines, armor, large bodies, speed -warning coloration, cryptic coloration, mimicry, flash coloration -behavioral modification

What are some examples of Müllerian mimicry?

-black grasshopper (blue belly) -underwing moth (blends in with bark, orange underwings) -chemical mimicry by orchids -coral snake and scarlet king snake

What happens when each of the assumptions are violated?

-there is selection -there are mutations -there is migration -there are chance events (genetic drift) -mates are not chosen at random

What are insertions and what are some examples?

a mutation involving the addition of one or more nucleotide pairs to a gene

What are cryptic species?

a species that cannot be distinguished from similar species by easily identifiable morphological traits

What is negative frequency-dependent selection?

rare phenotypes are favored by selection

What are deletions and what are some examples?

a mutation in which one or more pairs of nucleotides are removed from a gene

What are the forms of barriers that prevent gene flow that make allopatric speciation possible?

geographical, pre and post-zygotic, mating, social, seasonal

Hardy-Weinburg Assumptions

1. organisms are diploid 2. only sexual reproduction occurs 3. generations are non overlapping 4. mating is random 5. population size is infinitely large 6. allele frequencies are equal in the sexes 7. no migration, mutation, or selection

Hardy-Weinburg Conditions

1. population must be very large 2. population must be isolated from other populations 3. no mutations 4. random mating 5. no natural selection

How can evolution function as the engine for biodiversity?

it allows for two species to exist simultaneously because alleles don't fixate as a result of the coevolutionary arms race

Founder effects relationship with population size?

it's a smaller population

What are somatic mutations?

mutations that affect cells in the body of an organism -can affect all the daughter cells produced by the affected cell and can affect the phenotype of the individual. -in plants, somatic mutation can be passed down during vegetative production

What can happen as a result of inbreeding?

offspring can die quickly and or can have complications throughout their lives -haspburg family children (half of them) didn't make it to their 1st birthday

Endosymbionts

a cell that lives within a host cell -mutalistic

What is genetic drift?

a change in the allele frequency of a population as a result of change events rather than natural selection. -eliminates alleles faster in smaller population than larger ones. -bottleneck is a form of genetic drift

What is an extinction vortex? Explain the example in the book and generate your own hypothetical example.

a downward population spiral in which inbreeding and genetic drift combine to cause a small population to shrink and, unless the spiral is reversed, become extinct

What is fixation and when does it occur?

a fixed allele is one that remains in a population when all of the alternative alleles have disappeared -no genetic variation exists at a fixed locus within a population because all individuals are genetically identical at that locus

Metapopulation

a group of spatially separated populations of the same species that interact at some level -ex: exchange alleles

What is a selection coefficient? What does the values tell you?

a measure of the strength of natural selection for or against a specific phenotype or genotype

Hardy-Weinburg Equilibrium

a situation in which allele and genotype frequencies in an ideal population do not change from one generation to the next -occurs when there is no selection, no mutation, no migration, no genetic drift, and when random mating occurs -when alleles are not in this, evolution is occurring

Define adaptation

a trait or integrated suite of traits that increase the fitness of the possessor -not all phenotypes are necessarily adaptive

Mutualists

a type of symbiosis in which both organisms or populations are benefited -creates positive frequency dependent

What is pre-zygotic reproductive isolation?

aspects of the genetics, behavior, physiology, or ecology of a species that prevent sperm from one species from fertilizing eggs of another species -reduce the likelihood that a zygote will form

What is post-zygotic reproductive isolation?

aspects of the genetics, behavior, physiology, or ecology of a species that prevent zygotes from successfully developing and reproducing themselves

How does negative-frequency dependent selection work?

ex: two different colored flowers when one color starts to disappear from the population, it's fitness relative to the other colors increases, 'pulling it back from the brink' until it becomes common again. -when it becomes too common, the fitness of the other color increases, and it then spreads in the population

What are point mutations?

gene mutation in which a single base pair in DNA has been changed

What is an indels?

genetic markers in natural populations that can refer to either insertions or deletions