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Evolution
Dr. Krupa UKY BIO303 2nd test terms
113
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Undergraduate 3
02/24/2016

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Term
Coevolution
Definition
Reciprocal evolutionary change between interacting species, driven by natural selection
Term
Reciprocal selection
Definition
Selection that occurs in two species, due to their interactions with another; the critical prerequisite of coevolution
Term

Coevolutionary Escalation

(Coevolutionary arms race)

Definition
Species interact antagonistically in a way that results in each species exerting reciprocal directional selection on the other.
Term

Predator-Prey Conflict

 

Definition
Evolutionary arms race with no end
Term
Name some Anti-predator adaptions
Definition
  • Toxins, spines, arm, large bodies, etc
  • Warning coloration (aposematic coloration)
  • Cryptic coloration (camouflage coloration)
  • Mimicry (of a model/environment)
  • Flash coloration
  • Behavorial modification
Term
Name some Predator adaptations:
Definition
  • Mimicry
  • Cryptic coloration
  • Speed
  • acute senses
Term
Batesian Mimicry
Definition
Occurs when harmless species resembles harmful or distasteful species, deriving protection from predators
Term
What are the coevolutionary relationships associated with Batesian Mimicry?
Definition

For Model-Mostly neutral, sometimes negative

For Mimic-Always Positive

For Predator - Negative

Term
Mullerian mimicry
Definition
Occurs when several harmful or distasteful species resemble each other in appearance, facilitating the learned avoidance of predators
Term
What are the coevolutionary relationships associated with Mullerian Mimicry
Definition

For Model- Always Positive

For Mimic- Always Positive

For Predator- Negative

Term
Endosymbiosis
Definition
 
 
  1. Symbiosis in which one of the organisms lives inside the other.
Term
Adaptation
Definition
A trait or integrated suite of traits that increase the fitness of the possessor
Term
Adaptive
Definition
Having a trait that shows or has a capacity for or tendency towards adaptation
Term
Negative frequency-dependent selection
Definition
When the relative fitness is higher in rare genotypes and less in common ones
Term
When does selection occur?
Definition
When genotypes differ in their relative fitness
Term
The outcome of selection depends on what?
Definition
The frequency of an allele as well as its effects on fitness
Term
When does drift have more of an effect on the population?
Definition
When populations are small
Term
How can drift effect selection? (Enhance by ____, oppose by _____)
Definition
  • Enhance- by removing harmful alleles that have been driven to low frequency by selection
  • Oppose- by removing beneficial alleles
Term
Inbreeding coefficient
Definition
The probability that the two alleles at any locus in an individual will be identical because of common descent.
Term
Heterozygote advantage
Definition
Occurs when selection favors heterozygote individuals over either the dominant homozygote or recessive homozygote
Term
What is the ultimate source of heritable genetic variation?
Definition
The gradual accumulation of mutations within populations
Term
Gene flow
Definition
The movement/migration between of alleles between individuals of different populations
Term
Pleiotropy
Definition
when a mutation in a single gene affects the expression of more than one different phenotypic trait
Term
Fitness
Definition
success of an organism at surviving and reproducing, thus contributing offspring to future generations
Term
Founder effect
Definition
Describes the loss of allelic variation that accompanies founding of a new population from a very small number of individuals
Term
Bottleneck (genetics)
Definition
An event in which the number of individuals in a population is reduced drastically
Term
genetic drift
Definition
Random, nonrepresentative sampling of alleles from a population during breeding; causes the allelic composition of a population to change between generations
Term
When does selection have more of an effect on the population?
Definition
In large populations
Term
Morphospecies concept
Definition
species designation and identification is based on the morphological differences between populations
Term
What concept is the primary way fossils are assigned?
Definition
Morphospecies Concept
Term
Biological Species Concept
Definition
Species are groups of actually, or potentially interbreeding natural populations that are reproductively isolated from other such groups
Term
What concept is used for different populations that do not hybridize regularly in nature, or when they fail to produce fertile offspring?
Definition
Biological Species Concept
Term
Phylogenetic Species Concept
Definition
Identifies species as being monophyletic based on comparisons with other populations
Term
Which concept looks at genetic divergence as well as morphological traits?
Definition
Phylogenetic Species Concept
Term
What approach works on sexually and asexually reproducing plants, fossils, and in many cases prokaryotes?
Definition
Phylogenetic Species Concept
Term
Population genetics
Definition
study of allele distributions and frequencies
Term
What is the allele outcome in populations affected by gene flow (migrations) from ancestor to later populations?
Definition
New alleles enter the population (Figure 6.3, pg. 165)
Term
What is the allele outcome in populations affected by genetic drift from ancestor to later populations?
Definition
Purple allele is lost (Figure 6.3, pg 165)
Term
What is the allele outcome in populations affected by mutations from ancestor to later populations?
Definition
New genetic variant appears in the population (Figure 6.3, pg. 165)
Term
What is the allele outcome in populations affected by natural selection from ancestor to later populations?
Definition
Red allele becomes less common (Figure 6.3, pg. 165)
Term
What is the allele outcome in populations affected by the Hardy-Weinberg equilibrium from ancestor to later populations?
Definition
Allele frequencies do not change (Figure 6.3, pg. 165)
Term
Fixed allele
Definition
Allele that remains in a population when all of the alternative alleles have disappeared.
Term
Antagonistic pleiotropy
Definition
When a mutation with beneficial effects for one trait also causes detrimental effects on other traits
Term
Negative selection
Definition
Selection that decreases the frequency of alleles within a population
Term
Positive selection
Definition
Selection that increases allele frequency in a population
Term
When does Negative selection occur?
Definition
Whenever the average excess for fitness of an allele is less than zero
Term
When does Positive selection occur?
Definition
Whenever the average excess for fitness of an allele is greater than zero.
Term
Additive allele
Definition
An allele that yields twice the phenotypic effect when two copies are present at a given locus than occurs when only one copy is present
Term

[image] 

This poorly drawn chart shows the effects of positive selection on additive, recessive, and dominant alleles. Match the line to the allele

Definition

Red-Dominant
Orange-Additive

Blue-Recessive

Term
What drives coevolution?
Definition
Natural selection
Term
How does coevolution affect species evolution?
Definition
By exerting selective pressure on the other species
Term
Positive/Positive mutualism
Definition
A relationship between species that raises each other's fitness
Term
Examples of Positive/Positive mutualism
Definition
  • Pollination
  • Seed dispersal
  • Nutrient exchange between mycorrhiza and plants
  • Farming
  • Animals and microbiota
  • Cleaners
Term
Give examples of coevolved adaptations of positive/positive mutualism
Definition
  • Bright colors on flowers attract insects and birds. Hummingbirds insert slender bills into flower tubes
  • Farmed fungi can grow only inside ant nests. Ants kill fungi that invade gardens
Term
Positive/Neutral Commensalism
Definition
A relationship in which one species benefits but the other suffers no loss of fitness
Term
Example of Positive/Neutral Commensalism
Definition
Scavengers
Term
Negative/Positve relationship
Definition
A relationship that leads to significant fitness loss for one species, but benefits the other.
Term
Examples of Negative/Positive relationship
Definition
  • Predator and Prey
  • Herbivores and plants
  • Deceptive pollination
  • Host and parasite
Term
Reciprocal selection
Definition
Selection that occurs in two species, due to their interactions with one another.
Term
What is a critical prerequisite of coevolution?
Definition
Reciprocal selection
Term
What is central to the dynamics of coevolution?
Definition
Geographic structure of population
Term
Species
Definition
Smallest evolutionary independent unit
Term
What is the smallest evolutionary independent unit?
Definition
Species
Term
What causes species to exist? (HINT: think isolation)
Definition
When they are genetically isolated from one another because of lack of gene flow
Term
[image]
Definition
[image]
Term
Diversifying coevolution
Definition
An increase in genetic diversity caused by heterogeneity of coevolutionary processes across the range of ecological partners
Term
What are the five conditions that must be met to achieve Hardy-Weinberg equilibrium?
Definition
  1. Population must be very large
  2. Population must be isolated from other populations
  3. No mutations
  4. Random mating
  5. No natural selection
Term
What are the fundamental conclusions provided by Hardy-Weinberg?
Definition
  1. The allele frequencies in a population will not change, generation after generation.
  2.  If the allele frequencies in a population are given by and q, the genotype frequencies will be given by (p2 + 2pq + q2).
Term
What are the assumptions underlying Hardy-Weinberg equilibrium?
Definition
  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
Term

When are homozygotes favored by selection?

Definition

In cases of additive alleles

 

"Favorable alles can be carried all the way to fixation because heterozygous individuals will have higher fitness than individuals lacking the allele, and homozygous individuals will fare even better. Eventually, the population will contain only individuals homozygous for the allele." (pg. 180) See figure 6.17, pg. 181

Term
Fixation
Definition
Change from a situation where ≤ two variants of an allele to a situation where only one of the alleles remains.
Term
When does fixation occur?
Definition

When all alleles in the population are the same

 

Exp:    Buri's experiment with Drosophila. At the start, most populations were p=0.5, he ended with most populations near p=1 (fixation) or p=0 (elimination)

Term
When does fixation occur rapidly?
Definition
In small populations
Term
Will fixation occur eventually?
Definition
Yes
Term
How does negative frequency-dendent selection work?
Definition
EXP: two different colored flowers

When one color starts to disappear from the population, its fitness relative to the other color 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
Term
What is an example of heterozygote advantage?
Definition
Sickle-cell anemia carriers
Term
[image]
Definition
[image]
Term
What is an example of balancing selection?
Definition
Heterozygote carriers of sickle-cell anemia. Heterozygotes makes the population more resistant overall to malaria, but also can cause sickle-cell anemia in population
Term
What impacts do mutations alone have on selection
Definition

Increase or decrease selection:

 

Negative selection

Postive selection

Term
Are mutations usually deleterious, beneficial, or neutral?
Definition
neutral
Term
What is the relationship between population size and mutation impact?
Definition
The impact of mutations will have more affect on smaller populations
Term

[image]

What type of relationship is this?

Definition
A nice one
Term
Sampling error
Definition
Only sampling a portion of the population, leaving the chance that alleles might be lost
Term
How does evolution involve sampling error?
Definition
Changes in gene frequency as a result of sampling error is called "genetic drift"
Term
What are the benefits of inbreeding?
Definition
Uniformity, increased prepotency, fixing of desired alleles
Term
What are the disadvantages of inbreeding?
Definition
Higher mortality, decreased fitness
Term
Metapopulation
Definition
Group of spatially separated populations of the same species that interact at some level (e.g., exchange alleles)
Term
Isolation barrier
Definition
an aspect of the environment that reduces or impedes gene flow from individuals of other species.
Term
What are the two forms of isolation barriers?
Definition
Geographic and reproductive
Term
Allopatry
Definition
Populations are in separate, non-overlapping geographic areas.
Term
Speciation
Definition
Evolutionary process by which new species arise
Term
What causes one evolutionary lineage to split into two or more lineages?
Definition
Speciation
Term
General lineage species concept
Definition
Idea that species are metapopulations of organisms that exchange alleles frequently enough that they comprise the same gene pool and therefore the same evolutionary lineage.
Term
Under what populations conditions does inbreeding have a minimal impact?
Definition
Large populations
Term
Inbreeding depression?
Definition
Reduction in the average fitness of inbred individuals relative to the of outbred individuals
Term
Extinction vortex
Definition
describes the process that declining populations undergo when "a mutual reinforcement occurs among biotic and abiotic process that drives population size downward to extinction"
Term
Genetic load
Definition
burden imposed by the acumulation of deleterious mutations
Term
symbiont
Definition
Two organisms that live in symbiosis with one another.
Term
What is Secondary contact
Definition
Speciation by isolation
Term
Pre-zygotic reproduction isolation
Definition
Barriers that impede gene flow after sperm or pollen has been transferred but before fertilization has occured
Term
What is an example of pre-zygotic reproductive isolation?
Definition

(Pre-mating) Mechanical: Damselfly aedeagi, Guppy fish

(Pre-mating) Behavorial: Greater Prairie Chicken, Sharp-tailed Grouse

Term
Post-zygotic reproductive isolation
Definition
Isolating barriers that act after a zygote begins to develop; hybrid offspring that are sterile or infertile
Term
What are examples of post-zygotic reproductive isolation?
Definition
Hybrid sterility: Mule, Zebroid
Term
Isolation by distance
Definition
Pattern in which populations that live in close proximity are genetically more similar to each other than populations that live farther apart.
Term
When does hybridization result in reinforcement?
Definition
In populations of increased areas of reproductive isolation selecting against hybrid offspring, or in areas in which the hybrids have lower fitness
Term
When does hybridization result in speciation?
Definition
When hybridization between two different species leads to a new species
Term
Allopatric speciation
Definition
speciation that occurs when biological populations of the same species become vicariant i.e. isolated from each other
Term
Sympatric speciation
Definition
Formation of two or more species from single ancestral species within the same geographical area
Term
When might sympatric speciation occur?
Definition
In self-fertilizing plants
Term
When might allopatric speciation occur?
Definition
River formation separating a population of moles
Term
What are the forms of barriers that make allopatric speciation possible?
Definition
geographical barriers
Term
Horizontal gene transfer
Definition
Transfer of genes b/t organsims in a manner other than traditional reproduction
Term
Bateson-Dobzhansky-Muller incompatibilities
Definition
genetic incompatibilities in hybrid offspring arising from epistatic interactions between two or more loci
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