Iowa High School Biology Vocabulary (36-Week Curriculum)

A comprehensive vocabulary review containing all 88 terms and their verbatim definitions from the 36-week high school biology curriculum.

Abiotic factor

A nonliving environmental component, such as sunlight, temperature, or water.

Biotic factor

A living component of an ecosystem, such as prairie grass or bacteria.

Population

Members of the same species living in the same area.

Community

All the populations of different species living in an area.

Ecosystem

A community and the nonliving environment with which it interacts.

Habitat

The place where an organism lives.

Niche

A species' use of resources and interactions within its environment.

Producer

An organism that makes organic food molecules using light or chemical energy.

Consumer

An organism that obtains energy by eating organisms or their products.

Decomposer

An organism that breaks down dead material and wastes, recycling nutrients.

Food web

A network showing feeding relationships within an ecosystem.

Trophic level

An organism's feeding position in a food chain or web.

Carrying capacity

The population size an environment can sustain over time under given conditions.

Limiting factor

A resource or condition that restricts population growth.

Competition

An interaction in which organisms use the same limited resource.

Symbiosis

A close relationship between organisms of different species.

Biodiversity

The variety of life at genetic, species, and ecosystem levels.

Carbon cycle

The movement of carbon among organisms, air, water, and Earth materials.

Nitrogen cycle

The movement and transformation of nitrogen through organisms and the environment.

Ecological succession

Change in a community's species composition over time.

Invasive species

A nonnative species whose introduction causes or is likely to cause harm.

Ecosystem resilience

An ecosystem's ability to recover after a disturbance.

Cell

The smallest unit that carries out the functions of life.

Organelle

A specialized structure within a cell that performs a particular job.

Cell membrane

A selectively permeable barrier that controls what enters and leaves a cell.

Nucleus

The organelle that contains most of a eukaryotic cell's DNA.

Prokaryote

An organism whose cells lack a nucleus and membrane-bound organelles.

Eukaryote

An organism whose cells contain a nucleus and membrane-bound organelles.

Diffusion

The net movement of particles from higher to lower concentration.

Osmosis

The diffusion of water across a selectively permeable membrane.

Tissue

A group of similar cells working together.

Organ

A structure made of different tissues working together.

Organ system

A group of organs working together to perform major functions.

Homeostasis

Maintenance of relatively stable internal conditions.

Feedback mechanism

A process in which a system's output affects its continued activity.

Cell differentiation

The process by which cells become specialized.

Scientific model

A representation used to explain, investigate, or predict a system's behavior.

Scientific theory

A broad explanation supported by extensive evidence and repeated testing.

Independent variable

The factor deliberately changed in an experiment.

Dependent variable

The response measured in an experiment.

Controlled variable

A factor kept consistent across experimental conditions.

Evidence

Observations or data used to evaluate a claim or explanation.

Hypothesis

A testable proposed explanation for an observation.

Carbohydrate

A molecule, such as sugar or starch, used for energy or structural support.

Lipid

A molecule, such as a fat or phospholipid, involved in energy storage and cell structures.

Protein

A molecule made of amino acids that performs structural or functional roles.

Amino acid

A building block of proteins.

Nucleic acid

A molecule, such as DNA or RNA, that stores or helps express genetic information.

Enzyme

A biological catalyst that speeds up a chemical reaction.

ATP

A molecule that transfers energy for cellular activities.

Photosynthesis

A process that uses light energy to build sugars from carbon dioxide and water.

Chloroplast

The organelle where photosynthesis occurs in plants and algae.

Cellular respiration

A process that transfers energy from food molecules into ATP.

Mitochondrion

An organelle where most ATP production occurs during aerobic respiration in eukaryotes.

Fermentation

A process that allows glycolysis to continue producing ATP without oxygen.

DNA

The molecule that stores hereditary information.

Gene

A segment of DNA containing instructions for a functional product, such as a protein.

Chromosome

A structure of DNA and associated proteins that carries genes.

Allele

An alternative version of a gene.

Genotype

The allele combination an organism has.

Phenotype

An organism's observable characteristics, influenced by genes and environment.

Dominant allele

An allele expressed in a heterozygote under complete dominance.

Recessive allele

An allele masked by a dominant allele in a heterozygote under complete dominance.

Homozygous

Having two identical alleles for a gene.

Heterozygous

Having two different alleles for a gene.

Mutation

A change in a DNA sequence.

DNA replication

The process of copying DNA.

Transcription

The production of RNA using DNA as a template.

Translation

The production of a protein using instructions carried by messenger RNA.

Mitosis

Nuclear division that usually produces two genetically identical nuclei.

Meiosis

Cell division that halves chromosome number and produces genetic variation.

Gamete

A reproductive cell, such as an egg or sperm.

Fertilization

The joining of gametes to form a zygote.

Genetic recombination

The reshuffling of genetic information into new combinations.

Biotechnology

The use of organisms, cells, or biological molecules to develop useful products or processes.

Evolution

Change in inherited characteristics of populations across generations.

Genetic variation

Inherited differences among individuals in a population.

Natural selection

A process in which inherited traits influence survival and reproductive success.

Adaptation

An inherited characteristic that increases reproductive success in a particular environment.

Biological fitness

An organism's reproductive success relative to others in its population.

Common ancestry

The sharing of ancestors by different organisms or species.

Fossil

Preserved remains, impressions, or traces of past life.

Homologous structures

Structures that share an evolutionary origin, even when their functions differ.

Speciation

The formation of new species.

Extinction

The permanent loss of a species.

Genetic drift

Random changes in allele frequencies, especially in small populations.

Gene flow

Movement of alleles between populations through reproduction.

Artificial selection

Human selection of organisms for breeding based on desired inherited traits.