Exam 3

Population

A group of individuals of the same species living in the same geographic area at the same time.

Population Ecology

The study of how and why the number of individuals in a population changes over space and time.

Population Thinking

A way of thinking that emphasizes the importance of variation among individuals in a population; the opposite of typological thinking, which ignores variance or considers it unimportant.

Range

The geographic distribution of a species.

Population Density

The number of individuals of a population per unit area.

Metapopulation

A population made up of many small, physically isolated populations connected by dispersal.

Immigration

The migration of individuals into a particular population from other populations.

Emigration

The migration of individuals away from one population to other populations.

Demography

The study of factors that determine the size and structure of populations through time.

Age Structure

The proportion of individuals in a population that are of each possible age.

Generation Time

The average time between a mother’s first offspring and her daughter’s first offspring.

Life Table

A data set that summarizes the probability that an individual in a certain population will survive and reproduce in any given year over the course of it’s lifetime.

Social Selection

A type of natural selection that favors individuals with social traits that improve their competition for any resources, including mates.

True Navigation

The type of navigation by which an animal can reach a specific point on Earth’s surface. Also called map orientation.

Polyandry

A type of mating system where one female mates with many males per breeding season.

Innate Behavior

Behavior that is inherited genetically, does not have to be learned, and is typical of a species.

Sexual Selection

A type of natural selection that favors individuals with traits that increase their ability to obtain mates or choose good mates.

Reciprocal Altriusm

Altruistic behavior that is exchanged between a pair of individuals at different times (i.e., sometimes individual A helps individual B, and sometimes B helps A).

Inclusive Fitness

The combination of (1) direct production of offspring (direct fitness) and (2) extra production of offspring by relatives in response to help provided by the individual in question (indirect fitness).

Ultimate Causation

In biology, the reason that a trait or phenomenon is thought to have evolved; the adaptive advantage of that trait.

Kin Selection

A form of natural selection that favors traits that increase survival or reproduction of an individual’s kin at the expense of the individual.

Coefficient of Relatedness

A measure of how closely two individuals are related. Calculated as the probability that an allele in two individuals is inherited from the same ancestor.

Communication

In ecology, any process in which a signal from one individual modifies the behavior of another individual.

Sex

The gamete-producing status of an individual, typically female (producing large gametes called eggs), male (producing small gametes called sperm), or hermaphrodite (only in non-human organisms, producing both eggs and sperm, either sequentially or simultaneously).

Polygyny

A type of mating system where one male mates with many females per breeding session.

Behavior

In biology, an action in response to a stimulus.

Polygynandry

A type of mating system where multiple females and multiple males engage in mating relationships with shared resources.

Culture

In cell biology, a collection of cells or tissue growing under controlled conditions, usually in suspension or on the surface of a dish of solid growth medium, In behavioral ecology, behavioral traditions passed on through social learning.

Optimal Foraging

The concept that animals forage in a way that maximizes the amount of usable energy they take in, given the costs of finding and ingesting their food and the risk of being eaten while they’re at it.

Proximate Causation

In biology, the immediate, mechanistic cause of a phenomenon (how it happens), as opposed to why it evolved,

Compass Orientation

A type of navigation in which movement occurs in a specific direction.

Cost-benefit Analysis

Decisions or analyses that weigh the fitness costs and benefits of a particular action.

Migration

In ecology, a seasonal long-distance movement of large numbers of organisms from one geographic location or habitat to another.

Monogamy

A type of mating system where one male mates with one female per breeding season, forming a pair bond.

Piloting

A type of navigation in which animals use familiar landmarks to find their way.

Foraging

Searching for food.

Behavioral Ecology

A discipline that focuses on behavioral adaptations that have evolved in response to ecological selection pressures; a subset of organismal ecology, which also includes morphological and physiological adaptations.

Learning

An enduring change in an individual’s behavior that results from a specific experience.

Altruism

Any behavior that has a fitness cost to the individual (lowered survival and/or reproduction) and a fitness benefit to the recipient.

Replacement Rate

The number of offspring each female must produce over her entire life to “replace” herself and her mate, resulting in zero population growth. The actual number is slightly more than two because some offspring die before reproducing.

Population Dynamics

Changes in the size and other characteristics of populations through time and space.

Cohort

A group of individuals that are the same age and can be followed through time.

Density Dependent

Referring to any characteristic that varies depending on population density.

Exponential Population Growth

The accelerating increase in the size of a population that occurs when the per capita growth rate is constant and density independent.

Logistic Population Growth

The density-dependent decrease in growth rate as population size approaches the carrying capacity.

Density Independent

Referring to any characteristic that does not vary with population density.

Per capita rate of increase

The difference between the birth rate per individual and the death rate per individual. AKA instantaneous rate of increase.

Life History

The sequence of events in an individual’s life from birth to reproduction to death, including how an individual allocates resources to growth, reproduction, and activities or structures related to survival.

Age Structure

The proportion of individuals in a population that are of each possible age.

Fertility

The average number of surviving children that each female has during their lifetime.

Intrinsic rate of increase

The rate of increase of a population when conditions are ideal (birth rates per individual are as high as possible and death rates per individual are as low as possible).

Zero Population Growth

A state of stable population size due to fertility staying at the replacement rate for at least one generation.

Population Density

The number of individuals of a population per unit area.

Survivorship

On average, the proportion of offspring that survive to a particular age.

Age-specific Fecundity

The average number of female offspring produced by a female in a certain age class.

Survivorship Curve

A graph depicting the percentage of a population that survives to different ages.

Net Reproductive Rate

The growth rate of a population per generation; equivalent to the average number of female offspring that each female produces over her lifetime.

Carrying Capacity

(K) The population size that can be sustained by resources for an extended period of time.

Fecundity

The average number of female offspring produced by a single female in the course of her lifetime.

Age Class

All the individuals of a specific age in a population.

Directed-Pollination Hypothesis

The hypothesis that flowers are adaptations that attract specific pollinators, increasing the likelihood that pollination will occur.

Micropyle

The tiny pore in a plant ovule through which the pollen tube reaches the embryo sac.

Ground Tissue

An embryonic tissue layer that gives rise to parenchyma, collenchyma, and sclerenchyma—tisses other than epidermis and vascular tissue.

Spores

(1) In bacteria, a dormant form that generally is resistant to extreme conditions. (2) In eukaryotes, a single haploid cell produced by meiosis; it is distinct from a gamete, however, in being able to grow into a multicellular, haploid organism through mitotic divisions directly (no fertilization required).

Pollen Tube

In flowering plants, a structure that grows out of a pollen grain after it reaches the stigma. The tube extends down the style, and two sperm cells travel through it to the ovule.

Zygote

The cell formed by the union of two gametes.

Meiosis

In sexually reproductive organisms, a special two-stage type of cell division in which one diploid (2n) parent cell produced haploid (n) cells (gametes); results in halving of the chromosome number and new combinations of genes in each haploid cell.

Polar Nuclei

In flowering plants, the nuclei in the female gametophyte that fuse with one sperm nucleus to produce endosperm. Most species have two.

Nectary

A nectar-producing structure in a flower.

Pollen Grain

In seed plants, a male gametophyte enclosed within a protective coat of sporopollenin.

Synergids

One of two cells flanking the egg in the female gametophyte; releases chemical attractants that direct pollen-tube growth.

Style

The slender stalk of a flower carpel connecting the stigma and the ovary.

Radicle

The root of a plant embryo

Dormancy

A temporary state of greatly reduced metabolic activity and growth in plants or plant parts (e.g. seeds, spores, bulbs, and buds).

Aggregate Fruits

A fruit that develops from a single flower that has many separate carpels.

Stigma

The sticky tip at the end of a flower carpel; pollen grains adhere to it.

Sporopollenin

A watertight material that encases spores and pollen of modern land plants.

Corolla

All of the petals of a flower.

Carpel

The female reproductive organ in a flower. Consists of stigma, to which pollen grains adhere; the style, through which the pollen tube grows; and the ovary, which houses the ovule.

Pericarp

The part of a fruit, formed from the ovary wall, that surrounds the seeds and protects them. Corresponds to the flesh of most edible fruits and the hard shells of most nuts.

Embryo Sac

The female gametophyte in flowering plants.

Gametophyte

In organisms undergoing alternation of generations, the multicellular haploid form that arises from a single haploid spore and produces gametes by mitosis and cell division.

Shoot Apical Meristem

A group of undifferentiated cells at the tip of a plant stem; these cells divide to produce new cells that can differentiate into mature shoot tissues.