Bio Keystones (copy 73-97)

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Genetic Engineering

A technology that includes the process of manipulating or altering the genetic material of a cell resulting in desirable functions or outcomes that would not occur naturally.

Genetically Modified Organism

An organism whose genetic material has been altered through some genetic engineering technology or technique.

Genetics

The scientific study of inheritance.

Genotype

The genetic composition of an organism with reference to a single trait, a set of traits, or the entire complement of traits of an organism.

Golgi Apparatus

An organelle found in eukaryotic cells responsible for the final stages of processing proteins for release by the cell.

Gradualism

A proposed explanation in evolutionary biology stating that new species arise from the result of slight modifications (mutations and resulting phenotypic changes) over many generations.

Habitat

An area that provides an organism with its basic needs for survival.

Homeostasis

The regulatory process in which an organism regulates its internal environment.

Homeostatic Mechanism

A regulatory mechanism that contributes to maintaining a state of equilibrium (e.g., thermoregulation, water regulation, and oxygen regulation).

Homologous Structure

A physical characteristic in different organisms that is similar because it was inherited from a common ancestor.

Hypothesis

A proposed, scientifically testable explanation for an observed phenomenon.

Impermeable

Not permitting passage of a substance or substances.

Incomplete Dominance

A pattern of inheritance in which two alleles, inherited from the parents, are neither dominant nor recessive. The resulting offspring have a phenotype that is a blending of the parental traits.

Inheritance

The process in which genetic material is passed from parents to their offspring.

Interphase

The longest‐lasting phase of the cell cycle in which a cell performs the majority of its functions, such as preparing for nuclear division and cytokinesis.

Intracellular

Located inside a cell.

Isolating Mechanisms

Features of behaviors, morphology, or genetics which serve to prevent mating or breeding between two different species (e.g., temporal isolation, ecological isolation, behavioral isolation, mechanical isolation, and gametic incompatibility, hybrid inviability (embryo is not viable), hybrid sterility (resulting adult is sterile), and hybrid breakdown (first generation is viable but future generations are not).

Law (Scientific)

A law that generalizes a body of observations. At the time it is made, no exceptions have been found to a law. It explains things but does not describe them; serves as the basis of scientific principles.

Limiting Factor

Chemical or physical factor that limits the existence, growth, abundance, or distribution of an individual organism or a population.

Lipids

A group of organic compounds composed mostly of carbon and hydrogen including a proportionately smaller amount of oxygen; are insoluble in water, serve as a source of stored energy, and are a component of cell membranes.

Macromolecule

A polymer with a high molecular mass. Within organisms there are four main groups: carbohydrates, lipids, proteins, and nucleic acids.

Mechanism (Scientific)

The combination of components and processes that serve a common function.

Meiosis

A two‐phase nuclear division that results in the eventual production of gametes with half the normal number of chromosomes.

Migration (Genetics)

The permanent movement of genes into or out of a population resulting in a change in allele frequencies.

Mitochondrion

A membrane‐bound organelle found in most eukaryotic cells; site of cellular respiration.