Comprehensive Biology & Ecology Vocabulary

A comprehensive set of vocabulary flashcards covering key biological and ecological terms presented in the lecture notes.

Trophic Level

A single step in a food chain or food web that indicates an organism’s position in the flow of energy.

Producer

A photosynthetic organism (e.g., grass) that converts solar energy into chemical energy and forms the base of a food chain.

Primary Consumer

An organism that eats producers; first‐level consumer (e.g., grasshopper).

Secondary Consumer

An organism that eats primary consumers (e.g., mouse).

Tertiary Consumer

An organism that eats secondary consumers (e.g., snake).

Quaternary Consumer

An organism that eats tertiary consumers (e.g., hawk).

Herbivore

A heterotroph that eats plants only (e.g., cow).

Carnivore

A heterotroph that eats animals only (e.g., lion).

Omnivore

A heterotroph that eats both plants and animals (e.g., bear, humans).

Decomposer

An organism (e.g., fungi, bacteria) that externally breaks down dead organic matter and recycles nutrients.

Detritivore

An organism (e.g., earthworm, vulture) that internally digests dead organic matter.

Energy Pyramid

A diagram showing the relative amount of energy available at each trophic level; ~10 % is passed upward.

Biomass Pyramid

A model that represents the amount of living organic matter at each trophic level; greatest at the base.

Pyramid of Numbers

A diagram indicating the relative number of individual organisms at each trophic level.

Biomagnification

Increase in concentration of harmful substances at higher trophic levels of a food chain.

Density-Dependent Limiting Factor

A factor (e.g., competition, predation, disease) that limits population size more strongly when populations are dense.

Density-Independent Limiting Factor

A factor (e.g., extreme weather, pollution) that limits population size regardless of density.

Exponential Phase

Period of rapid population growth due to abundant resources.

Carrying Capacity

The maximum population size that an environment can sustain; reflected by the plateau phase.

Ecological Succession

Predictable series of community changes following disturbance over time.

Primary Succession

Succession that begins on surfaces where no soil exists.

Secondary Succession

Succession that occurs where soil remains after disturbance.

Pioneer Species

First organisms (e.g., lichens, mosses) to colonize barren environments in succession.

Mutualism

A symbiotic relationship where both species benefit (+/+).

Commensalism

A symbiotic relationship where one benefits and the other is unaffected (+/0).

Parasitism

A symbiotic relationship where one benefits and the host is harmed (+/-).

Predation

Interaction where a predator kills and consumes prey.

Competition

Struggle among organisms for the same limited resources.

Carbon Cycle

Biogeochemical cycle in which carbon moves through photosynthesis, respiration, combustion, and decomposition.

Photosynthesis (Carbon Cycle)

Process that removes CO₂ from the atmosphere and converts it to glucose.

Respiration (Carbon Cycle)

Process that releases CO₂ back to the atmosphere from organisms.

Nitrogen Fixation

Conversion of atmospheric N₂ into soil nitrates by bacteria.

Denitrification

Process where bacteria convert soil nitrates back into atmospheric N₂.

Greenhouse Effect

Warming that results when greenhouse gases trap solar radiation in Earth’s atmosphere.

DDT

A pesticide that biomagnified in food chains, causing thin-shelled eggs in birds like bald eagles.

Acid Precipitation

Rain or snow with a low pH that harms aquatic life and vegetation.

Carbohydrate

Biomolecule of C, H, O used for short-term energy and structural support; monomer = monosaccharide.

Protein

Biomolecule made of amino acids; functions include enzymes, transport, and structure.

Lipid

Non-polar biomolecule for long-term energy storage and cell membranes; no true monomer.

Nucleic Acid

Polymer of nucleotides (DNA, RNA) that stores and transmits genetic information.

Dehydration Synthesis

Chemical reaction that joins monomers into polymers by removing water.

Hydrolysis

Reaction that breaks polymers into monomers using water.

Enzyme

Protein catalyst that speeds up chemical reactions by lowering activation energy.

Prokaryote

Cell lacking a nucleus and membrane-bound organelles (e.g., bacteria).

Eukaryote

Cell containing a nucleus and membrane-bound organelles (e.g., plant, animal).

Diffusion

Passive movement of molecules from high to low concentration.

Osmosis

Diffusion of water across a semi-permeable membrane from high to low water concentration.

Hypertonic Solution

Higher solute concentration outside the cell; cell loses water and shrivels.

Isotonic Solution

Equal solute concentration inside and outside; cell size remains stable.

Hypotonic Solution

Lower solute concentration outside; cell gains water and swells.

Active Transport

Energy-requiring movement of molecules from low to high concentration via ATP.

Endocytosis

Bulk transport process where cells engulf materials into vesicles.

Exocytosis

Bulk transport process where vesicles fuse with membrane to release materials outside.

Interphase

Cell-cycle phase of growth (G₁), DNA replication (S), and prep for mitosis (G₂).

Mitosis

Division of a eukaryotic nucleus producing two identical daughter nuclei.

Cytokinesis

Division of the cytoplasm resulting in two separate daughter cells.

Semi-Conservative Replication

DNA replication where each new molecule contains one original and one new strand.

Meiosis

Two-stage cell division producing four genetically unique haploid gametes.

Diploid

Cell with two sets of chromosomes (2n).

Haploid

Cell with one set of chromosomes (n).

Gene

A segment of DNA that codes for a protein or trait.

Allele

Different form of a gene, represented by letters.

Genotype

Genetic makeup of an organism (e.g., Aa).

Phenotype

Observable traits resulting from genotype (e.g., blue eyes).

Homozygous

Having identical alleles for a gene (AA or aa).

Heterozygous

Having two different alleles for a gene (Aa).

Dominant Allele

Allele that masks another and expresses in heterozygotes; written with a capital letter.

Recessive Allele

Allele expressed only when homozygous; written with lowercase letter.

Incomplete Dominance

Inheritance where heterozygous phenotype is intermediate between parents.

Codominance

Inheritance where both alleles are fully expressed in heterozygotes.

Multiple Alleles

More than two possible alleles exist for a gene (e.g., ABO blood types).

Transcription

Process of making RNA from a DNA template in the nucleus.

Translation

Process of assembling a protein at the ribosome using mRNA, tRNA, and rRNA.

Point Mutation

Mutation that substitutes a single nucleotide in DNA.

Frameshift Mutation

Mutation caused by insertion or deletion of nucleotides, altering the reading frame.

Gel Electrophoresis

Technique that separates DNA fragments by size in an electric field.

Karyotype

Visual display of an individual’s chromosomes used to detect abnormalities.

Pedigree

Chart showing genetic relationships and inheritance of traits through families.

Transcription Factor

Protein that binds DNA to regulate transcription initiation.

Fossil Record

Collection of fossils used to study past life and evolutionary history.

Biogeography

Study of species distribution over space and time.

Homology

Similarity due to shared ancestry (anatomical, molecular, or developmental).

Endosymbiosis

Theory that mitochondria and chloroplasts originated from engulfed prokaryotes.

Gradualism

Model of evolution with slow, steady change and many transitional forms.

Punctuated Equilibrium

Evolutionary model of rapid change followed by long periods of stasis.

Natural Selection

Process where organisms with advantageous traits survive and reproduce more successfully.

Adaptation

Inherited trait that increases an organism’s chance of survival and reproduction.

Speciation

Formation of new species due to reproductive isolation and genetic divergence.

Convergent Evolution

Evolution of similar traits in unrelated species due to similar environments.

Divergent Evolution

Accumulation of differences between related species leading to new species.

Coevolution

Reciprocal evolutionary change between interacting species.

Genetic Drift

Random change in allele frequencies, especially in small populations.

Gene Flow

Movement of alleles into or out of a population via migration.

Taxonomy

Science of classifying organisms in a hierarchical system.

Binomial Nomenclature

Two-part scientific naming system using genus and species (e.g., Homo sapiens).

Cladogram

Diagram showing evolutionary relationships based on shared derived traits.

Autotroph

Organism capable of producing its own food, typically via photosynthesis.

Heterotroph

Organism that must obtain food from other sources.

Virus

Non-cellular infectious agent that reproduces only inside host cells; causes diseases like flu or HIV.

Nitrogen-Fixing Bacteria

Microorganisms that convert atmospheric nitrogen into forms usable by plants.