AP BIO--All Modules

Innate behavior

A behavior that is performed without any previous experience

learned behavior

A behavior in which the individual’s experience in its environment plays a large role

cooperative behavior

A behavior that helps a member of the same species improve another individual’s fitness

endotherm

An animal that produces most of its heat as a by-product of metabolic reactions to maintain a warm and steady body temperature

ectotherm

An animal that obtains most of its heat to warm its body from the environment

metabolic rate

The number of calories burned by an organism over time while at rest

chemosynthesis

The biochemical process in which the energy of chemical compounds is used to build sugars

autotroph

Organism that obtains energy by photosynthesis or chemosynthesis. Also known as a producer

heterotroph

An organism that obtains energy by eating other organisms. Also known as a consumer

trophic levels

An arrangement of producers and consumers into successive levels that represents the movement of energy

per capita growth rate

The rate of population change divided by the size of the population

maximum per capita growth rate of a population

The maximum growth rate possible for a population living without any constraints (rmax)

exponential growth model

A model of a population that continues to grow rapidly over time in an exponential manner

carrying capacity

A limit on how many individuals can be supported in a given environment (K)

density-independent factor

Factors that reduce density regardless of a population’s size

density-dependent factor

Factors that limit population growth as its size increases

logistic growth model

A growth model that describes population growth when there is a density-dependent carrying capacity

simpson’s diversity index

An equation that quantifies the diversity of species in a community

predation

An interaction that involves one species killing and consuming another

parasitism

An interaction in which one species lives in or on another organism, known as the host

competition

An interaction between species that require the same limited resource

niche partitioning

a process where different species in an ecosystem divide up resources to minimize competition and allow multiple species to coexist

mutualism

A special type of symbiosis in which both species benefit in regard to their growth or reproduction

commensalism

An interaction in which one species receives a benefit while the other species is neither harmed nor helped

keystone species

Pivotal populations that affect other members of the community in ways that are disproportionate to their abundance or biomass

trophic cascade

When indirect effects are initiated by the presence of a predator

Disruptions to ecosystems

natural disasters, disease, etc

Adaptation

The close fit between an organism and its environment

Biodiversity

Biological diversity; the total number of species, or, more broadly, the diversity of genetic sequences, cell types, metabolism, life history, phylogenetic groups, communities, and ecosystems

Phylogenetic Tree

A tree-like diagram representing a hypothesis about the evolutionary relationships among populations or species

Node

In phylogenetic trees, the point where a branch splits, representing the common ancestor from which the descendant species diverged

Root

The base of a phylogenetic tree, representing the common ancestor or group from which all the organisms on the tree evolved

Selective pressure

The full set of environmental conditions, both abiotic and biotic, that influence the evolution of a population by natural selection

convergent evolution

The independent evolution of similar traits in different species as a result of similar environments or selective pressures

artificial selection

A form of directional selection similar to natural selection, but with selection done intentionally by humans, usually with a specific goal in mind, such as increased milk yield in cattle

sexual selection

A form of selection that promotes traits that increase an individual’s ability to find and attract mates

genetic drift

A random change in the frequency of an allele due to chance

bottleneck

An extreme, usually temporary, reduction in population size that may result in marked loss of genetic diversity and, in the process, genetic drift

founder’s effect

A type of genetic drift that occurs when only a few individuals establish a new population

migration

The movement of individuals from one population to another or to areas with no prior population

gene flow

The movement of alleles from one population to another through interbreeding between members of each population

nonrandom mating

Mate selection that is not random, but instead is based on genotype or relatedness

hardy-weinberg equilibrium

A state in which allele and genotype frequencies do not change over time, implying the absence of evolutionary forces. It also specifies a mathematical relationship between allele frequencies and genotype frequencies

morphological homology

An anatomical structure that is similar in two groups of organisms because it was present in the common ancestor of the two groups and retained over evolutionary time

molecular clock

The observation that the extent of genetic divergence between two groups is a reflection of the time since the groups shared a common ancestor

vestigial structure

A structure that has lost its original function over time and is now much reduced in size

fossil

The remains of a once-living organism

carbon 14

A radioactive isotope of carbon frequently used in radiometric dating

radiometric imaging

Dating ancient materials using the decay of radioisotopes as a yardstick, including the decay of radioactive C14 to nitrogen for time intervals up to a few tens of thousands of years, and the decay of radioactive uranium to lead for most of Earth history

half life

The time it takes for an amount of a substance to reach half its original value. Radioactive half-life is the time it takes for half of the atoms in a given sample of a substance to decay

invasive species

Non-native species that become established in new ecosystems

phylogeny

The history of descent with modification and the accumulation of change over time

cladogram

A type of phylogenetic tree that shows clades, or monophyletic groups

character

An anatomical, physiological, or molecular feature of an organism that varies among taxa

shared character

A character or trait that is present in two or more groups of organisms

derived character

A character or trait that is newly evolved; an evolutionary innovation

outgroup

A group of organisms that has an older common ancestor than the common ancestor of the group of interest, and therefore serves as a reference for evolutionary relationships within the group of interest

biological species concept (BSC)

The concept that “species are groups of actually or potentially interbreeding populations that are reproductively isolated from other such groups.” The BSC is the most widely used and accepted definition of a species, but cannot be applied to asexual or extinct organisms

niche

A complete description of the role a species plays in its environment, and of its requirements, both abiotic and biotic

prezygotic

Describes factors that prevent the fertilization of an egg

postzygotic

Describes factors that cause the failure of a fertilized egg to develop into a fertile individual

speciation

The process whereby new species are produced

divergent evolution

The process by which two groups of organisms become genetically and physically different from each other over time

allopatric

Describes populations that are geographically separated from each other

sympatric

Describes populations that are in the same geographic location

adaptive radiation

A period of unusually rapid evolutionary diversification in which natural selection accelerates the rate of speciation within a group, with new species adapted for specific niches

gradualism

The idea that species change slowly over time

punctuated equilibrium

The idea that species go through periods of relatively little change, which are interrupted by short periods of rapid change and diversification

extinction

The loss of a group of organisms, typically a species

RNA world hypothesis

The idea that the earliest cells relied on RNA for both information storage and catalysis

Gene Expression

The production of a functional gene product, such as a protein; the “turning on” of a gene

Transcription

The synthesis of RNA from a DNA template

Translation

The synthesis of a polypeptide chain corresponding to the coding sequence present in a molecule of messenger RNA

Gene Regulation

The various ways in which cells control gene expression

Plasmid

In bacteria, a small circular molecule of DNA carrying a small number of genes that replicates independently of the DNA in the bacterium’s circular chromosome

Replication Fork

The site where the parental DNA strands separate as the DNA duplex unwinds

Semiconservative replication

The mechanism of DNA replication in which each strand of a parental DNA molecule serves as a template for the synthesis of a new daughter strand

Helicase

An enzyme that separates the two DNA strands at the replication fork so that each strand can be copied during DNA replication

Topoisomerase

An enzyme that relieves stress on the DNA double helix that results from overwinding or underwinding during DNA replication and transcription

DNA polymerase

An enzyme that is a critical component of a large protein complex that carries out DNA replication

Primer

A short strand of DNA or RNA; in DNA replication, RNA is used as a primer for DNA synthesis

Leading strand

A daughter strand that has its 3′ end pointed toward the replication fork, so as the parental double helix unwinds, this daughter strand can be synthesized as one long, continuous polymer

Lagging strand

A daughter strand that has its 5′ end pointed toward the replication fork, so as the parental double helix unwinds, a new DNA piece is initiated at intervals, and each new piece is elongated at its 3′ end until it reaches the piece in front of it

DNA ligase

An enzyme that joins two DNA fragments together

Proofreading

The process in which a DNA polymerase can immediately correct its own errors by excising and replacing a mismatched base

Template strand

The strand of DNA that is used as a template, or model, for RNA synthesis during transcription. The template strand is also called the noncoding, antisense, and minus strand

RNA polymerase

The enzyme that synthesizes an RNA transcript from a DNA template

Nontemplate strand

The strand of DNA that is not used as a template, or model, for RNA synthesis during transcription. The nontemplate strand is the reverse complement of the template strand. The nontemplate strand is also called the coding, sense, and plus strand

Promoter

A regulatory region where RNA polymerase and associated proteins bind to the DNA molecule in the process of transcription

Primary transcript

The initial RNA molecule that comes off the template DNA strand

Messenger RNA

The RNA molecule that combines with a ribosome to direct protein synthesis; it carries the genetic “message” from the DNA to the ribosome

RNA processing

A chemical modification that converts the primary transcript into mature mRNA, enabling the RNA molecule to be transported to the cytoplasm and recognized by the translational machinery

GTP cap

The modification of the 5′ end of the primary transcript by the addition of a special nucleotide attached in an unusual chemical linkage; also called a 5′ cap

Poly(A) tail

The adenine (A) nucleotides added to the 3 ′end of the primary transcript

Exon

A sequence that is left intact in mRNA after RNA splicing, and is therefore expressed in the protein

Intron

An intervening sequence that is removed from the primary transcript during RNA splicing

RNA splicing

The process of joining exons and removing introns from the primary transcript

Alternative splicing

The process by which exons are joined together and introns are removed during RNA processing. A single gene can be spliced in different ways to yield different mRNAs and different protein products

Ribosomal RNA (rRNA)

Noncoding RNA found in all ribosomes that aid in translation

Transfer RNA (tRNA)

Noncoding RNA that carries individual amino acids for use in translation