BBIO 180 exam terms

Independent Assortment

How alleles are set up during metaphase 1 is where they are randomly distributed to gametes, leading to genetic variation.

Segregation

The process during meiosis where alleles for a trait separate so that each gamete receives only one allele for each gene.

Directional Selection

One extreme side of a trait is pushed for in selection. Happens in either direction, not both.

Stabilizing Selection

Selection that favors the average

Disruptive Selection

Selection that does not favor the average, splits selection into both directions away from the average.

Frequency Dependent Selection

Uncommon Variants are preferred

Genetic Drift

Change in genetic traits due to random chance. More frequent in small populations

Bottleneck Drift (Genetic Bottleneck)

Few survivors of an event have random allele frequency by chance

Founder Effect

Small founding population have random allele frequency by random chance.

Hardy-Weinberg

Null model for evolution that allows predictions of traits if no evolution is occuring

Tangled Bank Hypothesis

Genetic variation increases chances of success in a complicated world

Red Queen Hypothesis

States that organisms (usually bacteria) evolve against you, so we must evolve to keep up with it in a constantly changing environment.

Intrasexual Selection

Sexual selection based between members of the same sex

Sexual Dimorphosm

Differences in traits between male and females of a particular species

Fundamental Sex Asymmetry

Males and females of a species have intrinsically different investment levels with their offspring

Vestigial Structures

Structures present in the phenotype that are no longer used and indicate evidence of evolution

Convergence

Similar circumstances can lead to similar adaptations independently, creates analogous traits

Homology

Similarities inherited from common ancestors through only natural selection, creates homologous traits

Incomplete dominance

2 alleles come together to create a “blend” of the phenotype. I.E white and red allele create pink

Intersexual Selection

Sexual selection based on interactions between sexes of a species

Handicap Hypothesis

If males can incest in consequential traits, those traits must be strong for the female

Parasite Hypothesis

Bright colors in males mean strong resistance to parasites, and would be good genes for female

Developmental Stability

If male traits are symmetrical then they are resistant to developmental stress, must be strong genes for female

Sexy Son Hypothesis

Sexiness itself is good genes valid for female to choose a particular male

Group Selection

Idea that members will help a group “for the good of the group”

Inclusive Fitness/Kin Selection

Helping out family in altruistic context

Reciprocal Altruism

Altruistic acts between non-related individuals

Runaway Sexual Selection

Traits evolved by males for sexual selection that become too extreme, causing negative effects that can be recorrected by natural selection

Single Point Mutation

Single point in DNA sequence is mutated

Deletion Mutation

Particular sequence in DNA code is deleted

Inserted Mutation

Mutation where new DNA code is added in between the “normal” DNA code

Inversion Mutation

DNA code is in the wrong order, or inverted

Polyploidy Mutation

Mutation where extra sets of chromosomes are produced

Polygenic Genes

Phenotype is influenced by multiple types of genes

Direct Fitness

Idea of helping your own children to pass down genes

Indirect Fitness

Helping out relatives since part of your own genetic code will be passed down by helping

Heratability

How heritable traits are from parent to offspring

Genotypic Plasticity

Individuals ability to change phenotype in response to its environment (In the short term, not evolved in the long term)

Genetic Variation (in natural selection context)

1st component of evolution by natural selection

Heritability (in natural selection context)

2nd component of evolution by natural selection

Context/Struggle

3rd component of evolution by natural selection

Differential Survival and Reproduction

4th component of evolution by natural selection

r

Growth rate variable per capita (b-d)

k

carrying capacity variable

Life History Continuum

Idea of tradeoffs in having offspring. High # offspring, tradeoff for lower survival rate. Low # offspring, tradeoff for higher survival rate

Competitive Exclusion

2 species can’t coexist when competing for the same limiting resource (ie, same water source). Have the same niche

Age structure

age distribution of a population

Abiotic factors

non-living factors that influence a population

Biotic factors

living factors that influence a population

N

variable for population size

lx

Variable for survivorship in life tables

mx

variable for fecundity in life tables

fecundity

average offspring per age

average #of offspring in a lifetime

What lx * mx gives you

r-max

(b-d) under ideal conditions or density independent growth

r-actual

(b-d) under density dependent growth (logistic growth)

r gets smaller

trend of r in higher density populations in logistic growth

r=0

r at carrying capacity (k)

maximum sustainable yield

(k/2), where you can reap the most of a population without permanently affecting it in logistic growth

Intraspecific Competeition

competition within the same species in a population

interspecific competition

competition between different species within a population

Fundamental Niche

Where an organism can theoretically live (in the absence of competition) with its given niche

Realized niche

where an organism actually lives when accounting for competition in an ecosystem

Exploitation

Type of interspecific competition where the 2 organisms never fully interact. one organism does all the work, the second organism takes the resources

Interference

Type of interspecific competition where one organism directly interacts and limits resources for another organism

Coexistance

One outcome of overlapping niches. Realized niche is lived in over fundamental niche and these different species now live in the same environment.

Niche Differentiation

Outcome of overlapped niches. In the long term, and both organisms evolve where their fundamental niches no longer overlap

Character Displacement

Change in characteristics that allows for niche differentiation. Evidence of ghost of competition past

Ghost of competition past

Competition between 2 species is no longer present due to niche differentiation via evolution

Additive Mortality

Killing of 1 creature does not create “chain reaction” and N of the ecosystem is lower than when it started

Compensatory mortality

Idea of mortality and a “chain reaction” killing one organism allows another to live (such as the dead organisms natural prey). Change in N=0

Refugia

Promotes coexistence of predator-prey through prey being able to hide

Prey Switching

Factor that allows for longterm predator-prey coexistence. When 1 type of prey has low N, predator has the option to eat another organism.

Complex habitats

Factor that promotes longterm predator-prey coexistence. Diverse ecosystem has variation so it is not a constant deathmatch between predator and prey.

Constitutive defenses

Defenses evolved by prey that are always present

Inducible Defenses

Defenses evolved by prey that must be “activated", typically due to energy cost to maintain

Top down regulation

Population is regulated by a predator eating its prey

Bottom up regulation

population is regulated by prey affecting predator. (ex: venom in plants regulating deer populations)

Species richness

How many species are in a community

Species composition

different Types of species in a community

Specialist

Type of species with specialized niche that thrives in a non-changing, high energy, stagnant environment

Generalist

Organism with a non-specialized niche/characteristics that thrive in variable, low energy, and unpredictable environments

Productivity

term that typically is the measurement of biomass

r-selected species

species with maximized reproductive output. has little parental care as a result and thrive in high disturbance environments

k-selected species

Species that are good at competing and surviving, and prefer low disturbance environments

Intermediate Disturbance hypothesis

If disturbance rate is in the middle, allows for maximum species richness by allowing both k and r selected species to thrive.

Net primary production

amount of energy available to transfer to a higher trophic level

Nutrient cycling

Conservation of matter, all nutrients are cycled through trophic levels

Primary Production

Making organic compounds from inorganic compounds (plants turning sunlight into glucose via photosynthesis)

Outcomes of primary production

Majority of primary production energy is lost as heat, only so much to transfer to next trophic level

Energetic hypothesis

Species number is regulated by the amount of energy passed down from 1 trophic level to the next

Pyramid of production

Pyramid diagram showing amount of energy available in different trophic level (take away is overall idea, not name memorizing)

Inverted pyramid of production

Pyramid of production can be inverted due to lower levels having low biomass but reproduce a lot which allows a lot of energy for the next trophic level (broad idea is takeaway)

Tree of life

metaphor created by Darwin that shows how species evolved from each other and shows common ancestors. basis of phylogeny

Speciation

Branch of phylogenetic tree where new characteristics are form and a new species is present

Derived Similarity (monophyletic group)

Shared characteristics due to common ancestor.

Convergent Similarity (Polyphyletic group)

Shared traits that were evolved independently and do not indicate relatedness

Primitive Similarity (Paraphyletic Group)

Shared characteristics due to a primitive ancestor, does not indicate organisms are closely related.

Outgroup analysis

Analysis by taking characteristics from an outgroup, which help indicate whether trait is monophyletic or paraphyletic on phylogenetic tree

Parsimony

Simplest explanation of evolved traits in phylogenetic tree is preferred. Helps determine polyphyletic traits on phylogenetic tree