Evolutionary Biology Exam 3 Study Guide

Cooperation

the fitness gains for both participants

Selfishness

Actor gains, recipient loses

Spite

Fitness loss for both participants

Hamilton's explanation

Believe that spite is a theoretical possibility if the recipient is negatively related to the actor

Wilson's explanation

Believe that spite can be favored without negative relatedness if the act also specifically benefits positively related individuals

Altruism

Fitness gain for recipient, cost for actor

Belding Ground Squirrel Calls

When predators approach, the squirrels give an alarm call. 8% of the squirrels are killed when they trill compared to 4% of non-trillers

Explanations of Altruism

females are more likely to give alarm calls because mothers, daughters, and sisters are more likely to assist each other in chasing off trespassers compared to unrelated individuals

Kin Selection

a type of natural selection that favors altruistic behaviors towards relatives

Hamilton's Rule

Altruistic behavior will spread if the benefit to the recipient(B) and the cost to the actor(C) are greater than 0. (Br - C > 0)

Inclusive fitness

TOTAL FITNESS = DIRECT + INDIRECT

Indirect fitness

results from reproductive increase due to help given by relatives

Direct fitness

results from personal reproduction

Greenbeard Effect

A gene helps its carrier grow a visible trait (like a 'green beard'), recognize that trait in others, and act kindly toward them.

Parent-offspring conflict

Mothers begin to ignore or push their young away near the end of the weaning period. Offspring will scream or attack the mother. Fitness interests are not symmetrical

Offspring related to themselves

r=1

Parents related to offspring

r=0.5

White Fronted Bee Eaters case study

Young adult bee-eaters often skip breeding to help raise siblings—building nests, feeding, and defending.

Blue-footed ******* case study

Commit siblicide by pushing the second egg from nest immediately.

Reciprocity

A mutual exchange of benefits between individuals.

Evolutionary Game Theory

used to analyze cooperation and conflict using a payoff system, like economics.

Vampire bats case study

Vampire bats live in small social groups and often fail to feed. If a bat starves for 3 nights, it can die.

Manipulation

altruism by the donor may be manipulating by the recipient

Mutualism

2 or more individuals will each gain a net survival or reproductive benefit

Eusociality

group living that has a hierarchy of working groups

Haplodiploidy Hypothesis

Queen ants lay equal numbers of male and female eggs (1:1 ratio), but workers prefer more females (3:1).

Best of a bad situation Hypothesis

building a complex nest and caring for many larvae would be impossible for a female to do by herself.

High predation rates and dependency of young

A concept discussing how young organisms are affected by predation and their reliance on parental care.

Paper wasp case study

Workers are not sterile, females may reproduce on their own, and pursue 3 strategies: initiate their own nest, join a nest as a helper, wait for a breeding opportunity.

Mole rat case study

Naked mole rats are highly inbred (r = 0.81), but still have group conflict. Workers are more related to their offspring than to others.

Queen's control in mole rats

The queen maintains control by shoving slower workers, especially distant relatives, to keep them working and enforce eusociality.

Life history analysis

The branch of evolutionary biology that tries to sort out reproductive strategies, balancing among fitness aspects.

Possum case study

Female nurses for 3 months and then weans. Continues to grow for several months until reaching sexual maturity. Has 1st litter of 8 offspring, and then months later has 2nd litter of 7 offspring.

Sand Cricket case study

Females are either short-winged or long-winged. Short-winged individuals devote more energy to reproduction and less to flight, illustrating trade-off energy allocation.

Senescence

The late-life decline of fertility and probability of survival, where aging reduces fitness.

Rate of living hypothesis

Predicts that because organisms have been selected to repair the maximum possible, species should not be able to evolve longer life spans.

Testing the rate of living hypothesis

Calculated the amount of energy expended per gram of tissue per lifetime for 164 mammal species, finding great variation in energy expenditure.

Longevity in fruit flies

Artificial selection for longevity increased life span from 35 to 60 days, with long-lived fruit flies having lower metabolic rates.

Telomeres

The tips of the chromosomes that consist of tandem repeats.

Evolutionary Hypothesis of Aging

Suggests that aging happens because natural selection weakens with age.

Collared Flycatcher

Polymorphic when they begin reproduction, with first-year breeders having higher reproductive success rates.

Opossum case study part 2

High adult mortality rates should lead to maturation earlier, with mainland opossums experiencing higher ecological mortality rates.

Offspring raising

The more offspring a parent attempts to raise at once, the less time and energy the parent can spend on each of them.

Lack's Hypothesis

Selection will favor clutch size that produces the most surviving offspring.

Great *** case study

Reveals inconsistencies with Lack's hypothesis, showing birds have smaller clutches than predicted.

Assumptions of Lack's Hypothesis

1. No tradeoff between parents' reproductive effort in one year and future survival and reproduction. 2. The only effect of clutch size on offspring is determining whether offspring survive. 3. Clutch size is fixed by a particular genotype.

Parasitoid Wasps

Inject eggs into a host insect, where larvae eat the host, pupate, and emerge, with larger clutches potentially reducing female fitness in unknown ways.

Principle of Allocation

States that if organisms use energy for one function, the amount of energy available for other functions is reduced.

Smith and Frewell Study

Created a mathematical plot of expected parental fitness versus offspring size, based on two assumptions: tradeoff between size and number of offspring, and individual offspring survival correlated to size.

Sand beetle case study

Seed beetles lay eggs on seeds, where larvae burrow, feed, and pupate, with females laying larger eggs on poor-quality palo verde seeds.

Genomic Imprinting

Occurs during gamete production in ovaries and testes.

IGF-case study

A hormone that is stimulant and binds to the IGF-II receptor. (Insulin-like growth factor II) is only transcribed paternally. The maternal allele codes for an alternative IGF-II binding site, which equalizes the flow of resources to each embryo.

Biological Invasions

The phenomenon where some species become invasive.

Campions Case study

Campions are innocuous in Europe, but invasive in North America. This is caused by evolution since their introduction. In North America, they're able to grow faster and replicate at a faster rate. Therefore, fitness grew.

Cholera Case Study

An epidemic that struck London. First known epidemiological study. John Snow proposed that the spread of cholera was through the poison of water.

Epidemiology

The study of incidence, frequency, distribution, and control of infectious disease in defined populations.

Germ Theory

Proposed that the existence of tiny microorganisms in the atmosphere was germs that caused diseases. It was proven wrong by observing patients who were having symptoms of the gut as opposed to the lungs.

Flu Case Study

Assumed that flu strains with novel antigenic sites will have selective advantages.

Antigenic sites

Specific parts of a foreign protein that the immune system recognizes and remembers.

Antibiotic Resistance

Are chemicals that kill bacteria by disrupting particular biochemical processes. For populations of bacteria, an antibiotic quickly becomes a powerful selective agent. When applied, the antibiotic quickly sorts the tolerant individuals from the non-tolerant individuals.

Evidence of Pathogen Sensitivity

Evidence shows that some pathogens revert to sensitivity.

Evolution of Virulence

The process by which pathogens evolve to the optimal level of virulence.

Recent Entrance Hypothesis

Pathogens evolve to the optimal level of virulence. Natural selection may select higher or lower virulence depending on the rate of transmission.

Coincidental Evolution Hypothesis

Some pathogens are not natural human pathogens and have not evolved with humans, but they may occasionally infect humans and make them sick.

Short-sighted evolution hypothesis

Because pathogens reproduce within hosts, traits that increase their short-term fitness may be detrimental.

Transmission rate hypothesis

Pathogens that are easily transmitted can have very high virulence. Pathogens that are difficult to transmit must have lower virulence, or they will kill the host without being transmitted.

Tissue Evolution

Cells of an individual may express different alleles because of heterozygosity.

Cancerous cells

Cancerous cells have new mutations.

COVID case study

Caused by novel coronavirus (SARS-CoV-2). Coronaviruses are a large family of viruses that cause mild to moderate upper-respiratory tract illnesses, like the common cold.

SARS-CoV-2

Has an insertion of 12 nucleotides for the spiky protein. This can help bind to the human cells.

Lactose intolerance case study

Lactase is an enzyme that breaks down milk sugar. Human populations that have a long history of drinking cow's milk have a heritable ability to continue producing lactose.

Manipulation hypothesis

Fever may represent manipulation of the host by the pathogen.

Adaptive defense hypothesis

Fever may be an adaptive defense against pathogens.

Male reed buntings case study

Male reed buntings adjust parental care effort determined by whom they feed.

Species Concepts

Theoretical definition of what constitutes a species.

Mayr's biological species concept

Species is defined as a freely breeding population that must have reproductive isolation from all members of other species.

Morphological species concept

Proposed that morphological similarity determines species membership.

Phylogenetic species concept

A species is the smallest diagnosable cluster of individual organisms within which there is a parental pattern of ancestors and descent.

Evolutionary species concept

An evolutionary species is a single lineage of ancestor-descendent populations that maintains its identity from other lineages.

Speciation

The process involving population isolation, divergence of phenotypes and genotypes, and reproductive isolation.

Allopatric Speciation

Populations are separated by a physical barrier and diverge.

Sympatric Speciation

Complete panmictic mating and a reproductive isolating mechanism evolve within the population.

Maggot fly case study

Apple and Hawthorn Maggot Flies became isolated despite being in the same area due to differing egg-laying preferences.

Paraparticle speciation

Populations diverge over an environmental gradient.

Peripatric speciation

A peripheral section of a population breaks off to form a distinct population.

Hawaiian Fruit Flies case study

Small groups of flies evolved quickly due to genetic drift and new environments, leading to the creation of a new species.

Polyploidy

Creates barriers to gene flow that are not geographic.

Secondary Contact

If populations come back into contact after isolation, they will have the opportunity to interbreed.

Prezygotic barrier

Includes mate choice, time of breeding, and genetic incompatibility.

Postzygotic isolation

Occurs when offspring are sterile or have lower viability.

Reinforcement hypothesis

Predicts that pre-mating isolation will evolve in species in secondary contact.

Hybridization

Common in plants and birds, occurring when recently diverged populations overlap.

Basin sagebrush

Found at low elevations.

Mountain sagebrush

Found at high elevations.

Hybrids

Have superior fitness in transitional habitats.

Stable persistence

Hybrid zones may persist indefinitely, with selection maintaining step clines at some loci.

Reproductive isolation

Selection may favor alleles that enhance prezygotic isolation, resulting ultimately in full reproductive isolation.

Fusion

Alleles that improve the fitness of hybrids may increase in frequency, potentially leading to two populations becoming one species.

New Species

Hybrids could evolve reproductive isolation from parent forms, becoming a third species.

Haldane's rule

Pattern of sterility is in the heterogametic sex, regardless of which is male or female.