Animal Behavior Exam 4

Reproduction

What is ‘Asexual Reproduction’?

Offspring are genetically identical to the parent

Done through: Binary Fission, Budding, Regeneration, and Parthogenesis (“virgin birth”)

What is a disadvantage of Asexual reproduction?

Limited genetic variability with this form of reproduction

What is an advantage of Asexual reproduction"?

Low cost to find a mate with this form of reproduction

What is ‘Sexual Reproduction’?

Offspring are genetically a 50-50 mix of each parent (siblings are a different 50-50 mix than parents unless they are identical twins)

Not all sexual behavior leads to reproduction**

What is the term for random variation due to an Assortment of Chromosomes?

Meiosis

Sexual Dimorphism

Sometimes individuals within the same species, but of a different sex, are easy to distinguish from one another due to unique physical/behavorial features

Sexual Selection (Theory from Darwin)

A special form of natural selection that acts on an organism’s ability to successfully reproduce with a mate

Intra-sexual Selection

Members within one sex physically compete with each other for access to the other sex (selection pressure is limited to one sex)

Inter-sexual Selection

Individuals of one sex choose which individual(s) of the other sex to take as mates. One sex tries to impress the other sex (selection pressure on both sexes)

Assortative Mating

a variation on sexual selection where individuals choose mates based on phenotypic similarity

*Is believed to play an important role in speciation*

Parental Investment (Trivers, 1972)

The amount of energy parents put into producing and raising their offspring (making gamates, gestation, fertility window, parental care)

What do sex differences in parental investment produce?

A biased operational sex ratio

What is a ‘Cuckhold’?

A male who invests parental effort in offspring that are not genetically their own (a subordinate male can hold this over an alpha male)

What are the three reproductive morphs of sunfish?

Parents, Sneakers, and Satellites

What is ‘Cryptic Female Choice’?

a female might ultimately use the sperm of a later partner to fertilize her eggs

What two ways has sperm evolved?

**In number and design**

Direct Fitness Benefits

factors that improve the fitness of the selecting individual (e.g., a female may select a mate who provides her with resources or protection)

Indirect Fitness Benefits

factors that improve the fitness of the selecting individual’s offspring (e.g., a female may select a mate who provides her offspring with resources, protection, and good traits)

Non-beneficial Choice

factors that influence the female’s choice but don’t appear to increase the fitness of her or her offspring

What are ‘Nuptial Gifts’?

a food item bestowed by males on females as part of courtship and copulation rituals (e.g., the size of the nuptial gift might determine how long the female will mate with the male)

Proxy Cues

An observable trait that is coincidentally linked to a trait that is favored by natural selection (ex., body coloration)

What does body symmetry have to do with female mate choice?

females usually prefer males with symmetrical body features

Koinophilia

“common-loving”

Exaggerated Traits

traits that are so extreme they appear to be a fitness advantage

Sexy Son Hypothesis

it is to the female’s advantage to have sons who sport the preferred trait

Good Genes Hypothesis

because they are so costly, only males with good genes have the extra resources to produce and maintain them

Sexual Imprinting

An early-life learning process involving a parent or caregiver that influences mate preferences later in life

Eavesdropping (Intersexual Selection)

extracting information from interactions between others (e.g., two males fighting) that can be used for future mating choices

Sexual Strategies

Evolved solutions (psychological and behavioral mechanisms) to adaptive problems faced by ancestral males and females that implicitly biased their approach to short- and long-term mating

What are “Good Financial Prospects”?

females of many species show a strong preference for males offering resources (both direct and indirect- food or good genes)

Personal Ads

a source of information that has been used to study human mating behavior (studies show that females desire males with strong financial resources)

How are personal ads “advantageous”?

Ads provide easily accessible data across many cultures and generations

Ads are real behavior in the real world

What are some disadvantages of Personal Ads?

Ads could be real but may not be honest

Coding of ads could be biased

Older Man Theory

Females’ biased preference for older males may stem from our hunter-gatherer ancestry when, compared to younger males, older males had superior physical/mental characteristics

What male shoulder to hip ratio is viewed as the most attractive by females?

1.6 (may be a sign of strength and agility)

What mate characteristic was valued as the highest in a cross-cultural study of males and females?

Love and Commitment

Behaviors associated with these characteristics: kindness, cooperation, emotional stability, and fidelity

What is the connection between human females and Parental Investment?

Human females are still biased by an evolutionary underlying sexual psychology related to selecting good mates

What is the purpose of ‘bumping’ during a “Bump Test”?

this action helps females determine the male’s physical ability to defend the nest

What are some adaptive risks to mating with an unhealthy male?

• mate could become debilitated or die prematurely

• mate could transfer communicable diseases or viruses to chooser or offspring

• if health is partly heritable, bad genes might be passed on to offspring

Dowry

Father pays groom’s family to marry his daughter (could be used as a sort of insurance plan)

Bride Price

father pays bride’s family to marry his son

Female Fertility

probability of becoming pregnant at a given time point

Reproductive value

The number of offspring a person of a given age and sex is likely to have beyond a given time point (peaks at age 19-20)

Why might Jealousy be an adaptation?

• this emotion could alert individuals to threats to a valued relationship

• becomes activated in the presence of interested and more desirable rivals

• functions as a motivational mechanism to deter infidelity