Exam 2 Vocab words

key words from each unit

Selfish Herd Effect

describes how individuals can reduce risk of predation by moving to specific positions with the group 

"Solitary" societies

♀ or ♂ + ♀ ♂ 

Polygynous group

(harem) ♂ + ♀♀♀♀

Permanent groups with complex structures

marsupials, ungulates, elephants, cetacean, primates and some carnivores

Matrilineal

ancestry is traced through the mother's family

Matrilineal society

(matriliny) group adhering to a kinship system in which ancestral descent is traced through maternal lines

Matriarchal society

(matriarchy) social system in which the mother or a female elder has absolute authority over the family group

coterie

Family unit, 1 adult ♂, 2-3 adult ♀ and all of their young less than 2 yrs old (1-26 individuals)

Example: Black-Tailed Prairie Dogs

The Lex Paradox

All of the ♂ in the lek come from the same highly evolved gene pool in which no ♂ offers anything more (no genetic advantage to the ♀) than any other male "displaying" in the lek

If all the ♂ are the same, there will be no way for ♀ to tell which ♂ are the fittest and therefore who to pick to mate with and the whole system will collapse

How is variation being maintained in the face of strong selection?

Promiscuous

no strong pair-bonds (Sexual dimorphism)

Monogamous

one male/ one female

• ♂ and ♀ w/ monogamous mating systems have similar external morphologies (monomorphy)

Polygamous

one individual mating w/ several others

Polygyny/ Polygynous

one ♂ mates with many ♀; the ♂ are usually more showy and larger than the ♀

Polyandry/ Polyandrous

one ♀ mates with many ♂; the ♀ are often more showy than the males

Bateman's principle

the sex which invests the most in offspring will become a limiting resource over which the other sex competes (= sexual selection)

Lorenz theory

Motivation to fight is similar to motivation to eat or drink, building up over a period of time, and then released as expression of the behavior

The parent-offspring conflict

It describes the evolutionary conflict arising from differences in optimal parental investment (PI) in an offspring from the standpoint of the parent and the offspring.

PI is any investment by the parent in an individual offspring that decreases the parent's ability to invest in other offspring, while the selected offspring's chance of surviving increases

Obligate siblicide

when a sibling almost always ends up being killed 0

The insurance Egg Hypothesis

When both eggs hatch successfully, the second or the B-chick, is the "marginal"

Facultative Siblicide

the siblicide may or may not occur, based on environmental conditions

Allelomimetic behavior

constantly moving together

Epimeletic behavior

giving care to others

Altruism

helpful behavior that lowers the helper’s reproductive success while increasing the reproductive success of the individual being helped

Reproductive Success (RS)

the production of independent offspring per breeding attempt or lifetime

Anisogamy

difference in the size of and gametes

Gametic investment

sperm are “cheaper” than eggs; female: a greater level of parental investment; Male can easily produce enough sperm to fertilize all of a female’s eggs

Sexual dimorphism
Sexual dimorphism

the two sexes of a species differ in external appearance

Fecundity selection

number of offspring produced

Fisher’s “runaway” hypothesis

mate choice originally evolved to facilitate adaptive choice for traits conferring a survival advantage

• Sons inherit trait that makes them sexually

  attractive; daughter inherit the majority

  mate preference

Zahavi’s “handicap” hypothesis

extravagant ♂ traits are costly to develop and maintain, only males

in good condition (those with good genes) will be able to fully develop and maintain an ornament

Heteropaternal superfecundation

same mother different fathers. can happen in cats and dogs

Group Selection

Type of natural selection that acts on all members of a group: the whole group is favored over another group

Direct selection

the process of natural selection that occurs when hereditarily distinctive individuals differ in the number of surviving offspring they produce or number of genes they pass on to subsequent generations

Direct fitness

a measure of the reproductive or genetic success of an individual based on the number of its offspring that live to reproduce

“Kin” or Indirect selection

the process that occurs when hereditarily distinctive individuals differ in the number of non-descendant relatives (not their offspring, but its relatives) they help survive to reproduce

Indirect fitness

a measure of the genetic success of an altruistic individual based on the number of relatives (or genetically similar individuals) that the altruist helps reproduce that would not otherwise have survived to do so

Inclusive fitness

a total measure of an individual’s contribution of genes to the next generation by direct and/or kin (indirect) selection

Group selection

the process that occurs when groups differ in their collective attributes and the differences affect the survival chances of the groups

Behavioral strategy

an inherited behavioral pattern that is in competition with other hereditarily different behavior patterns in ways that have the potential to affect an individual’s inclusive fitness. E.g., the willingness of individuals to assist close relatives even though their help reduce their direct fitness

Coefficient of relatedness

the probability that an allele in one individual is present in another because of both individuals have inherited it from a recent common ancestor; the probability that two individuals share an allele due to recent common ancestry

Hamilton’s Rule

The Inclusive Fitness Theory: a gene for altruistic behavior would be favored by natural selection if: rB > C

rB - C > 0

Cost to Actor

rB - C > 0

Benefit to Recipient

rB - C > 0

Coefficient of their genetic relatedness

Direct fitness

is gained through the production of offspring

Indirect fitness

is gained through the reproduction of non-descendant relatives

Inbreeding depression

the reduced survival and fertility of offspring of related individuals

The Selfish Gene

biological nature is entirely concentrated on the protection of one's own genes. It is possible for an individual to preserve its genes through its own self-sacrifice

Helpers

often older offspring of the parents and sibs of the young