eusosciality/coevolution Flashcards
What were the three key
ingredients needed for natural
selection to occur?
Variation
* Heredity
* Differential reproduction
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
What is eusociality?
highest level of sociality
and extreme altruism
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
what organisms are eusocial?
honey bees , bees
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
Why would natural
selection favor
cooperation and altruism?
kin selection
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
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
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
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%)
Phylogenetics is the study of what?
how evolutionary history can be inferred using patterns of common descent
What theory did Jean-Baptiste Lamarck propose?
inheritance of acquired characteristics
What relevance did James Hutton have towards evolution?
Earth is continuously being formed and is much older than previously thought
What relevance did James Hutton have towards evolution?
Earth is continuously being formed and is much older than previously thought
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
Uniformitarianism
Observable slow processes that occur over long stretches of time that can produce vast changes on Earth have been acting throughout geological history
What are the two “great laws” of descent with modification (evolution)?
Common descent and natural selection
Variation
Any difference between individuals of the same species
Inheritance
some traits are heritable through genes
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
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)
Sexual selection
Natural selection selects for traits that increase reproductive success
Males tend to have higher reproductive success if they do what?
Mate with multiple females
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