eusosciality/coevolution Flashcards by Diyana Mufeed

What were the three key
ingredients needed for natural
selection to occur?

Variation
* Heredity
* Differential reproduction

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Detail different levels of sociality observed in the natural world

Presocial – sociality beyond
courtship and mating, but
Subsocial – aggregations;
parental care of young for some
length of time
Parasocial – communal living,
but everyone takes care of their
own needs/young
Quasisocial – community works
together to care for young
Eusocial – “true” social
Sociable Weaver Bird Nests

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What is eusociality?

highest level of sociality
and extreme altruism

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What three criteria are used to define a eusocial group?

Division of labor with a caste
system
 sterile worker class(es) assist
reproductive class
 Only a fraction of population
reproduces
2. Cooperation among group
members in rearing offspring
3. Overlap of generations
capable of contributing to
colony function and living in
single group

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what organisms are eusocial?

honey bees , bees

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How are cooperation and altruism related to social behaviors?

Cooperation: two or more
individuals interact in a way
that leads to mutual net
benefits from joint actions
 But sometimes free riders
cheat
Altruism: behavior that
benefits others at cost of
fitness of the altruist

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Why would natural
selection favor
cooperation and altruism?

kin selection

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Describe the three evolutionary paths to eusociality.

Kinship: individuals who are related behave altruistically to
each other.
 Natural selection favors traits that pass on genes; related
individuals have similar genes

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Describe the three evolutionary paths to eusociality. second path

Reciprocity: individuals benefit by exchanging acts of
altruism.
 Natural selection favors reciprocal exchange wherein costs are
paid back

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Describe the three evolutionary paths to eusociality. third path

Group Selection (?): natural selection acts at the level of
the group
 Natural selection favors (altruistic) traits in the individual that
are advantageous to the group

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How has kin selection been used to explain the evolution of eusociality in Hymenoptera?

Haplodiploidy: sex
determination system in
Hymenoptera
* Males are haploid, females
are diploid
* Assuming one mating by
queen:
 female Hymenoptera workers,
on average, share 75% of
alleles (vs. genetic relatedness
in human siblings = 50%)

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Phylogenetics is the study of what?

how evolutionary history can be inferred using patterns of common descent

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What theory did Jean-Baptiste Lamarck propose?

inheritance of acquired characteristics

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What relevance did James Hutton have towards evolution?

Earth is continuously being formed and is much older than previously thought

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What relevance did James Hutton have towards evolution?

Earth is continuously being formed and is much older than previously thought

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What relevance did Charles Lyell have towards evolution?

observable geological processes, such as the formation of the Earth’s crust, occurred over a very long period of time in a gradual manner

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Uniformitarianism

Observable slow processes that occur over long stretches of time that can produce vast changes on Earth have been acting throughout geological history

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What are the two “great laws” of descent with modification (evolution)?

Common descent and natural selection

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Variation

Any difference between individuals of the same species

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Inheritance

some traits are heritable through genes

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Adaptation
exaptation

adaptation an inherited trait that makes an organism more fit in its abiotic (nonliving) and biotic (living) environment

exaptation traits that currently served a specific function but used to serve a different function in the past

Difference between adaptation and exaptation
Explain this

Adaptation is for traits that serves the same function as it did in the past while exaptation is when a trait has a different function compared to the past

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The difference between Darwin and Lamarck’s Theory is?

The difference between Darwin and Lamarck’s Theory is?
Explain this

Darwin’s Theory is a branching tree of life (descendant evolution) while Lamarck’s is independent progression (independent evolution)

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Sexual selection

Natural selection selects for traits that increase reproductive success

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Males tend to have higher reproductive success if they do what?

Mate with multiple females

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Why is male reproductive success more strongly tied to mates available than females?

Males are only limited by the amount of mates available while females are limited by gamete production and the costs of rearing the young

What are the four models of intersexual selection?

Direct benefits, good genes, Fisherian sexual selection, and sensory bias

How is the handicap principle related to good genes?

How is the handicap principle related to good genes? Explain this costly behaviors or physical features that reduce survival chances indicate high-quality genes

What two hypothesis were tested in the zebra finch study?

immune function is limited by carotenoid availability and females prefer the most carotenoid rich males

What is pangenesis?

The idea that each part of the body produces a characteristic seed that is released by males and females during mating, resulting in offspring with blended traits.

What is the Law of Segregation?

Each cell contains two copies of a gene (allele) that are segregated from each other in gamete formation so that each gamete receives only one copy

What is the Law of Independent Assortment?

Alleles for different genes are inherited independently of each other as long as they are unlinked

Who coined the term gene and what was the definition for it at the time?

Wilhelm Johannsen coined this term to name the hereditary factors described by Mendel

How did the white-eyed mutant fly experiment confirm the Chromosomal Theory of Inheritance?

How did the white-eyed mutant fly experiment confirm the Chromosomal Theory of Inheritance? Explain this Recognized that eye color and sex were both tied to chromosomes; genes are located on chromosomes like beads on a string and some of these are linked together

Who published and established the DNA structure?

Wattson and Crick

What is Epigenetics?

Heritable mechanisms that alter gene expression without altering the DNA sequence itself

Somatic mutations do not generate heritable variation required for evolution by natural selection

true

Mutations generate genetic variation and are random with respect to their fitness consequences

true

What is the Hardy-Weinberg Model?

Mathematical model that allows prediction of allele and genotype frequencies in a population under certain conditions

What are the five conditions of Hardy-Weinberg?

very large population, no migration, no mutations, random mating, no natural selection

What is the biggest assumption when finding equilibrium genotype frequencies using the Hardy-Weinberg equation?

random mating occurs

Directional selection

A shift in phenotype frequencies towards one extreme, eventually favored allele will become fixed in population

What happens if there is positive frequency-dependent selection?

Fitness increases as trait becomes more common

What happens to deleterious alleles in mutation - selection balance?

Remain at low, steady numbers in the population when rate of deleterious alleles created by mutation equals the rate it is eliminated by selection

What are some common consequences of inbreeding depression?

Reduced size, decreased fertility, increased congenital diseases, and increased deleterious recessive conditions

What is the difference between non-random mating vs sexual selection?

Differential reproduction

Migration

Migration Explain this Migrating individuals (emigrant/immigrant) bring new alleles into or out of a population and change the gene pool.

Genetic drift

due to random chance causes allele frequincies to fluctuate

bottleneck effect

Loss of genetic variation due to a drastic reduction in population size due to natural causes

Populations that have experienced the bottleneck effect are more susceptible to genetic drift because of?

Lower genetic diversity

What are some factors that can cause a population to become small?

Bottleneck effect, founder effect

What happens to variation if there is genetic drift?

Variation decreases since heterozygosity decreases and alleles can become fixed

Founder effect

Founder effect Explain this New population moves to a new area with only a few members of the original population

2 billion years ago

First eukaryotes

1.1 billion years ago

First multicellular organisms

luca

last universal common ancestor; common ancestral cell from which all cells descended

What are the essential elements of life?

carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur

Early Earth

No life, simple chemical compounds such as H2O, CH4 (methane), H2S (hydrogen sulfide), and NH3 (ammonia)

What is the Abiogenesis hypothesis?

Chemical formation of life from nonliving material

Oparin-Haldane Theory

Formalized the "warm little pool" idea by proposing abiogenesis from prebiotic soup

What were the results of the Miller-Urey Experiment?

Depending on the gases used, different amino acids were produced

Staying together model

Single cell divides, but parent cells do not separate from daughter cells. Genotypes of all cells are clones.

Coming together model

Free-living cells join together. Genotypes are potentially diverse

Why did selection favor evolutionary transitions?

Selection favored the transition not because of the ultimate benefits, but because of the initial direct benefits to the individual

What are some example of prezygotic barrier traits?

Habitat, temporal (breeding times), behavioral, mechanical (physical), and gametic (aquatic)

What are some example of postzygotic barrier traits?

Reduced hybrid viability, fertility, and hybrid breakdown

What evolutionary forces occur during allopatric speciation?

Genetic drift and natural selection

What are the two models of allopatric speciation?

Vicariance model and the population isolate model

Vicariance model

Developmental of geographical barrier splits population

dispersal model

migration of part of population across pre-existing geographical barrier to new area; population that migrated may experience strong founder effects

What is parapatric speciation?

A gradient of selective conditions across an area result in a genotype/phenotypic cline instead of a geographical barrier

Hamilton's Rule

Level of sacrifice of an individual makes for a relative is directly proportional to the relatedness

In meerkats, another behavior that they exhibit is helping care for young. Adult helpers remain in the colony for a few years, feeding and caring for the young of the dominant female before having any of their own offspring. Which hypothesis explains the evolution of helping behavior based on group selection?

Caring for the young of the dominant female ensures that more young survive, improving the genetic quality and size of the colony.

Which hypothesis best explains why sentinel behavior is costly to the sentinel but has been selected for because the whole group benefits due to predator avoidance?

group selection

Which hypothesis best explains why sentinel behavior reduces the fitness of the individual sentinel because it reduces foraging time but has been selected for because it increases the indirect fitness of the sentinel by helping relatives avoid predation?

kin selection

Which hypothesis best explains why sentinel behavior is selected for because it benefits the sentinel more than any other individuals?

individual selection

Which hypothesis best explains why sentinel behavior is costly to the sentinel due to reduced foraging time but the sentinel will later benefit as other individuals rotate into the sentinel role?

reciprocity

Evidence suggests that meerkat sentinel behavior is not altruistic. Instead, selection has favored this behavior because the fitness benefit (reduced predation) outweighs the fitness cost (reduced foraging time). (T/F)

true