PBSI 311

Mating system

pattern of male–female pairings within a species

Sexual reproduction

combining genetic material from two parents to produce genetically unique offspring

Male

sex that produces small, motile gametes (sperm)

Female

sex that produces large, nutrient-rich gametes (eggs)

Disruptive selection

natural selection favoring extreme traits over intermediate traits

Hermaphrodite

organism that produces both eggs and sperm

Simultaneous hermaphrodite

organism that functions as male and female at the same time

Sequential hermaphrodite

organism that changes sex during its lifetime

Genetic recombination

shuffling of genes during meiosis that increases genetic diversity

Fertilization

fusion of gametes to form a diploid zygote

Asexual reproduction

reproduction without gamete fusion, producing genetically identical offspring

Cost of meiosis

sexual reproduction passes only half of a parent’s genes to offspring

Choosy females theory

females are selective because eggs are costly to produce

Choosy males

males become selective when they invest heavily in offspring

Bateman’s rule

males show greater variation in reproductive success than females

Monogamy

pairing of one male with one female

Polygyny

one male mating with multiple females

Polyandry

one female mating with multiple males

Polygynandry

multiple males mating with multiple females

Social monogamy

pair bonding without guaranteed genetic exclusivity

Genetic monogamy

pairing where mates are the only genetic parents of offspring

Extra-pair copulation

mating outside the primary social pair

Serial monogamy

forming a new pair bond each breeding season

Resource defense polygyny

males control resources that attract females

Female defense polygyny

males defend groups of females

Harem

group of females defended by a single male

Lek

area where males gather to perform courtship displays

Lek polygyny

mating system where females choose among displaying males

Hotspot model

leks form where females are likely to pass through

Hotshot model

leks form around particularly attractive males

Scramble polygyny

males compete by searching for receptive females

Polygyny threshold model

females choose polygyny if benefits outweigh costs

Hormones and parental behavior

physiological regulation of parenting

Prolactin

hormone associated with parental care and milk production

Oxytocin

hormone involved in bonding, birth, and milk letdown

Brood patch

featherless area used to warm eggs

Parent-offspring conflict

conflict over optimal amount of parental investment

Begging

offspring signaling to obtain food

Weaning

termination of parental feeding

Honest signal

signal that accurately reflects need or quality

Dishonest signal

exaggerated or misleading signal

Brood parasite

species that relies on others to raise its young

Infanticide

killing of offspring, often to increase reproductive success

Territoriality

defense of an area against others

Aggression

behavior intended to harm or intimidate others

Social group

collection of individuals of the same species

Herd

group of grazing mammals

Flock

group of birds

School

group of coordinated fish

Pack

group of cooperative carnivores

Colony

large social group with structured roles

Dominance hierarchy

ranked social structure determining access to resources

Cost-benefit approach

evaluating behavior based on fitness costs and benefits

Social information

learning from others without direct cooperation

Direct cooperation

individuals working together for mutual benefit

Mutualism

cooperation where all parties benefit immediately

Altruism

behavior benefiting others at a cost to the individual

Reciprocal altruism

aid given with expectation of future return

Kin selection

behavior that benefits genetically related individuals

Inclusive fitness

total genetic contribution including relatives

Hamilton’s rule

altruism favored when rB > C

Eusociality

extreme cooperation with division of labor and reproduction

Reproductive skew

unequal distribution of reproduction within a group

Queen

reproductive female in eusocial species

Worker

non-reproductive individual performing colony tasks

Soldier

defensive caste in eusocial insects

Division of labor

specialization of tasks within a group

Task specialization

role differentiation based on ability or age

Age polyethism

task specialization based on age

Haplodiploidy

genetic system where males are haploid and females diploid

Social recognition

ability to identify group members

Social parasite

species that exploits social systems of others

Nest

structure used for shelter and raising young

Parental investment

resources devoted to offspring that reduce future reproduction

Biparental care

both parents provide care

Uniparental care

only one parent provides care

Territory

resource-defended area used for feeding or breeding