AP Biology

Biosphere

All parts of Earth where life exists

Deep Time

Earth and its biosphere changing dramatically over the billions of years.

Adaptation

A genetic trait of one or more individuals in a population that allows to survive and reproduce in a changing environment.

Population

a group of organisms that live in the same area.

Evolution

the change in the traits of populations over time.

Biodiversity

the variety of life on earth.

Ecosystems

all the interacting living and non-living things in a physical area.

Ecological succession

series of changes that occur in a community over time.

Disturbance

An event, such as storm, fire, flood, drought, overgrazing or human activity, that changes a community and alters resource availability.

"On the Origin of Species"

1859: Charles Darwin's book explained how various species evolve over time and only those with advantages can survive and reproduce

Natural selection

when organisms that adapt better to changing conditions survive, reproduce, and have more offspring.

Selective Breeding

Another type of evolution, but is driven by human input.

common ancestor

The shared ancestor all living things

phenotype

Physical expressions of genetic trait

descent with modification

the concept that all species have been modified over time with most species going extinct.

Tree of life

A diagram depicting the genealogical relationships of all living organisms on Earth, with a single ancestral species at the base.

inheritance of acquired characteristics

traits present in parents are modified, through use, and passed on to their offspring in the modified form

Epigenetics

the study of how environmental factors, including chemical signals in the cell triggered by stress and nutrition, can regulate gene expression.

stablizing selection

favors intermediate variations and reduces variation in a population.

Directional selection

Favors one of the extreme variants in a population, and occurs when there is an environmental change or when individuals of a population migrate to a different environment.

disruptive selection

favors the extreme and leads to increased variation.

Speciation

when a new species forms when members of a population become reproductively separated from one another until genes can no longer flow between them.

Morphological

members of a species have a similar structure and appearance.

Biological

the members can interbreed and produce viable, fertile offspring.

Gradualism

Evolution taking hundreds of thousands or millions of years to occur.

punctual equilibrium

New species appearing and disappearing gradually.

Gene pool

members of the same species sharing a common set of genes.

Reproductively isolated

Genes are unable to flow between populations.

allopatric speciation

The formation of new species in populations that are geographically isolated from one another.

sympatric speciation

The formation of new species in populations that live in the same geographic area

behavioral isolation

occurs when two populations are capable of interbreeding but have behaviors that prevent mating.

temperal isolation

occurs when two different populations mate at different times.

Mechanical isolation

occurs when the sexual organs between members of closely related, yet different, species do not fit together.

post zygotic barriers

occurs after fertilization. A zygote is formed, but the offspring are infertile or unviable.

Population genetics

examines how the frequencies of alleles in populations change over time.

Gene frequency

the ratio of an allele to the total of all other alleles of the same gene in the population.

Genetic diversity

occurs when there is a great variety of genomes within a population of organisms.

null hypothesis

an opposite hypothesis

Genetic drift

happens when the allelic frequencies in a population change due to chance.

bottleneck effect

a type of genetic drift that occurs when most of the population is killed off due to chance event such as fire, flood, volcano, or earthquake.

Founder effect

a type of genetic drift that occurs when a very small group of individuals populate a new area.

Extinction

the result of reduced genetic variation that make a species less able to survive and reproduce, therefore leading to a species being killed off.

Holecene Epoch

the sixth mass extinction which started 11,700 years ago, and is a result of human activity.

Anthropocene Epoch

A new epoch, a geological time segment with a distinctive characteristic.

Adaptive radiation

the emergence of numerous species from a common ancestor.

Divergent evolution

new species deriving from another species.

Convergent evolution

when different organisms, arising from different ancestors, have similar characteristics because they have adapted to similar environments.

Coevolution

when an evolutionary adaption in one species is dependent on another species and vice versa.

Hardy-Weinberg equilibrium

equation that mathematically measures gene frequencies in populations from generation to generation.

Microevolution

the change within small groups of organisms over a short period of time.

Macroevolution

the evolution of large groups of organisms over a long period of time.

Allele frequencies

how often dominant and recessive alleles show up in populations from generation to generation.

Heterozygous cross

Two heterozygous organisms are crossed.

Gene flow

the introduction or taking away of genes from the population can not be prevented.

radiometric dating

The ratio of a radioactive isotope to its non radioactive element is mathematically analyzed to find its age.

Distance measurements

similar fossils are found a great distance away from each other, and the age of fossils in one location is known, it can be assumed that the age of each group of fossils is the same.

Law of Superposition

Sedimentary rocks are always deposited one layer at a time.

transitional fossils

Fossils that show the intermediate body plans between old and new types of species.

Homologous structures

parts of animals that look similar to parts of other animals even if they perform different functions.

vestigial structures

structures on an organism which have lost function and atrophied (shrunk) through time.

apopotosis

programmed cell death

Biogeography

geographical distribution of species

The Modern Synthesis

the new movement fusing the principles of Darwin and Mendel together.

Theory of Evolution

states that organisms change and develop over time to adapt an increase rate of survival

natural selection

A natural process resulting in the evolution of organisms best adapted to the environment.

Taxa

organizing species into groups.

Phylogeny

the evolutionary history of a species or group of species.

lineage

the sequence of the species or a group that have evolved from a common ancestor.

Clade

a group of organisms that share a common ancestor and includes all the lineal descendants of that ancestor.

phylogenetic tree

a braching diagram illustrating phylogeny, the evolutionary relationship between species.

Root

common ancestor of all organisms of the clade.

Node

Locates the common ancestor of all taxa that follow.

cladistic analysis

one of the tools uses to create a phylogeny.

Cladogram

a special type of phylogenetic tree that uses shared and derived characters to determine which species are most closely related.

Shared characters

traits that are present in two or more lineages.

Derived characters

traits that occurred in the most recent common ancestor and were passed on to all the descendants.

Outgroup

distantly related species that serves as a basis for comparison.

shared ancestral character

A character that groups species together.

character table

allows the ability to record characters and reveal evolutionary relationships.

Protozoan

an animal-like protist.

Mold

a fungus-like protist

Algae

plant-like protists.

Xylem

vascular tissue responsible for transporting water up from the roots.

Phloem

transports sugars (sap) from the leaves to parts of the plant that do not undergo photosynthesis, such as the braces and roots.

Gymnosperms

seeded, non-flowering plants

Angiosperms

flowering plants

Monocot

angiosperm with one cotyledon

Dicot

angiosperm with two cotyledons.

multicellular heterotrophs

animals that must eat other organisms to obtain their energy.

Collagen

strong and flexible rope-like fibers that help support cells.

Hox genes

define the head-to-tail pattern of development in animal embryos.

radial symmetry

animals have all body parts radiating out from the center of the body.

bilateral symmetry

animals show a right and left side.

Ectoderm

outer later; develops into the skin, brain, and nervous system.

Mesoderm

middle layer; develops into the internal tissues and organs.

Endoderm

inner layer; develops into the internal tissues and organs.

Diploblastic

animals that lack the mesoderm layer, lacking complex internal organs.

Triploblasts

Animals with 3 tissue layers.

coelom

body cavity

Acoelomates

no body cavity