Chapters 9 and 10 Ecology

What is life history?

The series of events related to an organism's growth development and reproduction

What is allocation in life-history theory?

How organisms divide limited energy among growth reproduction and survival

What is phenotypic plasticity?

When one genotype produces different phenotypes depending on environmental conditions

What is sequential hermaphroditism?

When an organism changes sex during its lifetime

Why are larger clownfish typically female?

Egg production is energetically costly so larger individuals produce more eggs

What is anisogamy?

Gametes differ in size with large eggs and small sperm

What is isogamy?

Gametes are the same size

What is a disadvantage of sexual reproduction?

Populations grow more slowly because only half the individuals produce offspring

What is a major benefit of sexual reproduction?

Genetic recombination increases variation and adaptability

What is dormancy?

A state of suspended growth allowing survival during unfavorable conditions

Why are early life stages well suited to dormancy?

They require less energy to survive

What is dispersal?

Movement of offspring away from parents which can reduce competition and colonize new habitats

What is semelparity?

Reproducing once before death

What is iteroparity?

Reproducing multiple times during life

What are typical traits of r-selected species?

Short lifespan rapid development many offspring little parental care

What are typical traits of K-selected species?

Long lifespan slow development fewer offspring high parental care

Why do life-history trade-offs occur?

Energy and resources are limited so investment in one trait reduces investment in another

Why does offspring size often decrease as offspring number increases?

Energy must be divided among more offspring

How does parental investment affect offspring survival?

Higher investment generally increases survival probability

What is fitness in evolutionary biology?

Contribution of an individual’s genes to the next generation

What is behavioral ecology?

Study of how behavior contributes to survival and reproduction

What are the four major topics in behavioral ecology?

Finding food avoiding predators finding mates social behavior

What is optimal foraging theory?

Animals maximize net energy gained per unit time while foraging

What does profitability mean in foraging theory?

Net energy gained from food relative to time spent obtaining it

What factors influence food profitability?

Energy content search time handling time

Why might animals leave a food patch?

Food availability decreases as patch is used

What is a trade-off between foraging and predation risk?

Animals may eat less to avoid predators

What is an antipredator adaptation?

A trait or behavior that reduces risk of being eaten

Give an example of avoiding detection by predators.

Camouflage or being active when predators are inactive

Give an example of detecting predators early.

Increased vigilance in groups

Give an example of preventing attack.

Appearing toxic or difficult to capture

Give an example of escaping predators.

Playing dead or shedding a tail

What is the selfish herd hypothesis?

Individuals reduce predation risk by positioning themselves near others

What is the dilution effect?

Risk of predation decreases as group size increases

What is an advantage of living in groups?

Increased vigilance and predator defense

What is another advantage of living in groups?

Shared parental care

What is a disadvantage of living in groups?

Increased competition for food

What is another disadvantage of living in groups?

Greater disease transmission

Why is group size often intermediate?

Costs and benefits balance at moderate sizes

What is sexual selection?

Natural selection favoring traits that improve mating success

Why are males often more competitive for mates?

They invest less energy in gametes

Why are females often more selective in mate choice?

They invest more energy in eggs and offspring

What are ornaments in sexual selection?

Traits used to attract mates such as bright feathers

What are weapons in sexual selection?

Traits used to compete with rivals such as horns

Why might males show elaborate traits?

They signal genetic quality to females

Give an example where males provide more parental investment.

Seahorses where males carry embryos

How can predators influence mating behavior?

Individuals may avoid risky displays

What is a proximate cause of behavior?

Immediate mechanism producing behavior

What is an ultimate cause of behavior?

Evolutionary reason behavior increases fitness

Why can behavior evolve?

Heritable behaviors that improve survival or reproduction become more common