High Yield- Bio 120

List the views of the Classical School

• Most indv in pop = genetically uniform/homozygous. Theres is 1 optimal allele that max fitness

• Variation = low + polymorphism = rare

• Mutations are mostly deleterious + weeded out via purifying/negative selection

• Role of selection = eliminate rare/harmful allele

• H.J. Muller = key person

List the views of the Balance School

• Most indv in pop = heavily polymorphic

• Variation = high + highly heterozygotic

• Mutations = maintained by natural selection

• Frequency-dependent selection: fitness depends on how common/rare it is with rare variants being more advantageous

• Dobzhansky = person

List the views of the Neutral School

• Maj of genetic changes/polymorpshism = MOLECULAR level

• Genetic changes ≠ help/harm organism’s ability to survive + reproduce

• Fixed changes = neutral

• Evolution = constant steady rate (molecular clock hypothesis)

• Kimura = person

Define the molecular clock hypothesis

• Gene sequences (DNA/RNA/protein) evolve constant rate over time across diff organism

• Genetic diff between 2 species = proportional to time since they last shared common ancestor

• Fossil record used to calculate genetic diff → calendar yrs

Define neutral genetic drift

Random fluctuation of allele frequnece over time due to CHANGE (not natural selection). Involves mutations that DONT affect an organism.

Mutation rate = same rate if population is big/small because it is neutral

Define genetic drift

Mechanism of evolution where allle frequencies in population change over generations cuz of RANDOM chance not natural selection.

Strongly affects small + isolated population because rare allele can be lost/permament THUS lose genetic variation cuz of allele fixation

Distinguish between bottleneck effect and founder effect

Bottleneck: Sharp reduction in population size cuz of NATURAL disaster/human activity

Founder: Small group breaks off from large population. Causes limited gene pool

Define gene flow

Transfer of genetic material from 1 population to next

Causes increase of genetic diversity = new genetic traits introduce

Reduce diff in genes between 2 populations = more similar to eachother

Prevents speciation cuz stopping gene flow = not able to reproduce anymore (too diff genes)

Distinguish between stochastic and deterministic evolution

Stochastic: Population evolution = randomness + only probabilities determine not actual final outcome. Small population where accidental loss/survival can rlly change gene pool drastically

Deterministic: Population evolution is completely predictable if u know starting conditions. Not random. Strong natural selection. Large populations mostly

List the 3 diff types of phenotypic plasticity

1. Developmental plasticity: Phenotypic change that is NOT reversable. Happens during important life stage of organism

2. Acclimation: Phenotypic change that IS reversible during org lifetime.

3. Seasonal plasticity: Predictable phenotypic change over course of year.

Define reaction norms

Set of all phenotypes that single genotype can express under diff environmanetl conditions.

Graph that shows interaction of genotype in diff environment.

Distinguish between adaptive and maladaptive phenotypic plasticiy

Adaptive: Phenotype change from environment INCREASES fitness

Maladaptive: Phenotype change from environemt DECREASE fitness

Define phenotypic plasticity

Ability of organism to express diff alleles/phenotypes in response to environment

Define phenotypic polymorphism

Occurence of 2+ distinct/discrete forms (ex: ABO/diff hair color) of individuals in SAME species

Distinguish between monomorphic and polymorphic gene

Monomorphic: 1 common allele in population

Polymorphic: 2+ common alleles in population

Define metric genetic variation

Heritable diff in quantitative/continous traits (ex: height) that is ifluenced by multiple genes

Define polygenic

Traits that are influenced by multiple genes

Define agents of selection

Factors that influences individual’s ability to survive/reproduce. Can be abiotic/biotic/human-induced

Define speciation and its requirements

• Process where ancestral species splits into diff species

• Needs:

  • Interrupted gene flow (no same gene pool)

  • Reproductive isolation

  • Genetic divergence (diff gene changes over generation = more genetically diff so no interbreeding)

Distinguish betwen overt and covert combat

Overt: Physical combat between males for female mate. Stronger phys traits + delayed sexual maturity so more stronger

Covert: Non-direct combat for female mate. Kill other sperms/physcially attatch to female/ seal female reproductive tracts so no more sperm enter/ take out previous male sperm and inject own

Define sneaker male

Small male that place sperm in egg so father has to spend resources caring for offpsring that isn’t even his.

What are the 5 types of female mate choice?

1. Chooser Bias

2. Direct Selection

3. Good genes/Sexy Sons Hypothesis

4. Run-Away Selection

Define Chooser Bias

Female wired to notice colors/sensory things for survival and male adapts to be similar to color/sensory thing so female attracted to him

Define Direct Selection/Female Preference

Male provides gifts for female to survive. Female extremly choosy because of more E needed for offspring.

Define lekking species

Species where male gather in community (lek) to perform visual/phys courtship display to females

Define Good genes/Sexy Sons hypothesis

Ornaments = costly so if male survives because of them even tho its not beneficial to survival→ male is strong = offspring will also be fit cuz genes passed down

Define Bateman Principle

Production male sperm < E than egg in female.

Gradient/slop = relationship between # of mates + offspring.

Stronger sexual selection if parents have DIFF levels of investment to save more resources

Define Run-Away Selection

Attractive offspring more likley to find mate and thus reproduce more + survive

Attractive traits thus gets more accenutated + emphasized even tho its not good for survival (ex: big tail)

List the consequences of inbreeding

1. Loss of heterozygosity (harmful mutation = homogenous)

2. Loss of genetic diversity

3. Reduce fitness

4. Reduced fertility because of low reproductive success

List the factors/cause of inbreeding

• Small population size

• Geographical barriers = no outside gene pools for outcrossing

Define inbreeding depression

• Reduction of survival/fitness/fertility of offspring from inbreeding due to harmful genes + increases homozygosity

Distinguish between Tangled Bank hypothesis and Red Queen hypothesis

Tangled Bank: Spatial variation (diff niches in same environment). Sexual reproduction creates genetic variety so siblings does not occupy + fight over same niche/resources.

Red Queen: Temporal variation (diff environment over time such as weather). Species must CONSTANTLY ADAPT to survive predators that are ALSO adapting/evolving. So sexual reproduction makes it harder for fast-reproducing parasites to adapt to host generation cuz of recombination of genes

What does both Tangled Bank + Red Queen showcase?

• Benefits of sexual reproduction/its reason

List the benefits and costs of sexual reproduction

Benefits: Increased genetic diviersity = more chances of survival in diff environments

Costs: More E + time consuming

How was the Tangled Bank + Red Queen Hypothesis experimentally tested?

Tangled Bank: Microbial population in environemnt that was spatially homogenous (same resources/niche) + heterogenous (diverse and diff niche). Sexual reproduction occured more in spatially HETEROGENOUS environment.

Red Queen: Used snail sample across various lakes/streams.

Define transmission bias in context of sexual reproduction

Specific alleles/genes are passed to offspring higher than usual 50% from Menelian inheritance probability cuz of mating preferneces

Distinguish between parthenogenesis + clonal propgation

Parthenogenesis: Embryo develops from egg w/o fertilisation

Clonal propgation: Egg w/ fertilisation

Define traumatic insemination

Bypass female choice by piercing into female body wall + depositing sperm.

What is the cause of sexual conflict?

Reproductive adapttion increase fitness of 1 sex over cost of other

Define antagonistic coevolution

Male persistance traits + female resistance traits evolve as a result of eachother.

Define hybrid sterility

Inability of hybrid organism to produce fertile offspring because of chromosome mismatch

Define local natural selection

Process where specific environmental pressures in habitat favors certain heritable traits over others. More reproductive success for org only in that specific area

Define geographic variation

Diff in physical/genetic/behavioral traits across diff locations/regioins cuz of natural selection/adaptation to local enviornment/isolation

List the conclusions of Mendel’s Pea Plant Experiment

• Traits = DISCRETE + indepdnent units from parents (not blended)

• NOT blending inheritance (smooth/avg mix of parents’ characterisitics)

• Dominant allele masks recessive

• Law of Independent Assortment: Allele of seperate traits = independent from eachother so don’t mix (ex: height + eye color doesn’t affect eachother)

• Law of Segregation: Organisms has 2 alleles per trait and the alleles seperate during gamete formation so offspring only has 1 allele from each parent

List Darwin’s Postulates in order

1. Variation: Indiv of species show phenotypic variatioin

2. Heritability: Some indv variation = heritable

3. Overproduction/Competition: More offspring produced = struggle for existence because of compeittion for same/limited resources

4. Differential Survival/Reproduction = survival + reproduction is NOT RANDOM and determined by individual’s likeliness of surviving/reproducing

Define what Darwin meant by descent with modification

All living things = related

Offspring change over generations because of environment/natural selection/etc.

Define genetic hitchhiking/selective sweep

Neutral/harmful allele changes in frequency cuz its too close to a beneifical gene that is being promoted/increased because of natural selection.

Since genes located near each other on same DNA strand/chromosome inherited tgt, harmful/neutral gene is dragged along + spread alongside beneficial allele

Define valley of reduced diversity

Localized chromosomal region where genetic variation = decrease compared to rest of genome cuz of genetic hitchiking/selective sweep.