Comprehensive Biology Review: Principles of Life, Taxonomy, Microorganisms, Fungi, and Invertebrate Zoology

Vocabulary practice flashcards covering fundamental concepts across biology lecture notes: the scientific method, taxonomy, prokaryotes, protists, fungi, and invertebrate zoology.

Biology

The science that studies the origin and history of life, everything that was once alive, the structure of living organisms, how they function, and how they interact with each other.

Homeostasis

The regulation of an organism's internal conditions to maintain life and restore equilibrium whenever internal disturbances occur.

Adaptation

An inherited characteristic resulting from the adjustment of an organism's bodily structures to the specific functions they perform in an environment.

Hypothesis

A testable explanation formulated by scientists that can be supported by scientific evidence or revised if unproven.

Independent Variable

The single tested factor deliberately altered or manipulated by an investigator during an experiment to observe its effect on an outcome.

Dependent Variable

The factor resulting from and depending on changes made to the independent variable in a controlled experiment.

Taxonomy (Classification)

The grouping of objects or living organisms based on a set of shared characteristics to facilitate their study and identification.

Binomial Nomenclature

A formal naming system established by Carl Linnaeus where each species is assigned a two-part Latin scientific name: a capitalized genus name followed by a lowercase species epithet, written in italics.

Species

A group of living organisms possessing similar morphological and structural traits that are capable of interbreeding to produce fertile, viable offspring.

Characteristics of the Six Kingdoms

The six major kingdom taxa (Archaea, Bacteria, Protista, Fungi, Plantae, Animalia) classified by cellular type, presence of peptidoglycan, cellulose, or chitin in cell walls, cellularity, and autotrophic or heterotrophic modes of nutrition.

Peptidoglycan

A cell wall polymer consisting of alternating chains of two types of sugars linked by amino acids, providing a porous and strong structure in true bacteria but absent in archaea.

Nucleoid

The region within a prokaryotic cell where the main circular chromosome containing the organism's genetic material is located without a surrounding nuclear membrane.

Plasmid

A small, circular, self-replicating accessory ring of DNA present in some prokaryotic cells distinct from the primary bacterial chromosome.

Endospore

A dormant, resistant bacterial cell structure formed to withstand extreme environmental stress such as extreme heat, freezing, desiccation, and ultraviolet radiation.

Nitrogen Fixation

The biochemical conversion of atmospheric nitrogen gas ($N_2$) into nitrogen compounds usable by plants, carried out by specialized bacteria living inside the root nodules of legumes.

Normal Flora

Beneficial or harmless microorganisms inhabiting the human body that compete with pathogenic bacteria, preventing them from establishing disease.

Virus

A microscopic non-living strand of genetic material surrounded by a protein coat, ranging from $5$ to $300\,\text{nm}$, that cannot reproduce independently and must replicate inside a living host cell.

Capsid

The protective outer layer of protein that encloses and shields the viral nucleic acid genome (either DNA or RNA).

Retrovirus

A specialized RNA virus equipped with the enzyme reverse transcriptase that transcribes its viral RNA into DNA inside a host cell, such as the Human Immunodeficiency Virus (HIV).

Prion

A proteinaceous infectious particle that causes neurodegenerative diseases such as transmissible spongiform encephalopathies (mad cow disease) by inducing abnormal folding in normal cellular proteins.

Protozoa (Animal-like Protists)

Heterotrophic, unicellular eukaryotic protists classified primarily by their method of locomotion, including ciliates, amoebas, sporozoans, and flagellates.

Contractile Vacuole

A specialized organelle found in freshwater protists that actively collects and expels excess accumulated water from the cytoplasm to preserve osmotic balance.

Pseudopod

A temporary projection of the cytoplasm utilized by sarcodines such as Amoeba for cellular movement and phagocytic feeding.

Alternation of Generations

A reproductive life cycle alternating between a diploid ($2N$) multicellular sporophyte generation and a haploid ($1N$) multicellular gametophyte generation.

Chitin

A tough, flexible complex polysaccharide compound that comprises the cell walls of fungi and the rigid exoskeletons of arthropods.

Hyphae

The branching, threadlike microscopic structural filaments composing the vegetative and reproductive bodies of multicellular fungi, collectively forming a mycelium.

Phyla of Fungi

The major taxonomic divisions of kingdom Fungi (Chytridiomycota, Zygomycota, Ascomycota, Basidiomycota, Deuteromycota), distinguished by structural traits, hyphal division, and methods of spore generation.

Lichen

A symbiotic mutualistic organism formed by the close association of a fungus (typically an ascomycete) with a photosynthetic green alga or cyanobacterium.

Mycorrhiza

A mutualistic association between fungal hyphae and vascular plant roots, facilitating enhanced water and mineral uptake for the plant in exchange for synthesized carbohydrates and amino acids.

Bioindicator

A living organism that is especially sensitive to environmental pollutants or conditions, serving as an early biological warning system for environmental health.

Blastula

An early stage in animal embryonic development consisting of a fluid-filled hollow sphere of cells formed by rapid mitotic divisions of a zygote.

Gastrula

A developmental embryonic stage consisting of a two-layered sac of cells with an opening at one pole, from which the primary embryonic germ layers differentiate.

Radial Symmetry

A body plan arrangement that allows an animal to be divided into roughly equal halves through any longitudinal plane passing through a central axis, typical of cnidarians.

Bilateral Symmetry

A body plan arrangement in which an animal can only be divided into mirror-image left and right halves along a single longitudinal central plane.

Coelomate

A triploblastic animal possessing a true, fluid-filled internal body cavity entirely surrounded and lined by tissue originating from the mesoderm.

Pseudocoelomate

An animal possessing a fluid-filled body cavity that develops between the mesoderm and endoderm rather than completely within the mesoderm, characteristic of roundworms.

Acoelomate

An invertebrate animal with a solid body plan entirely lacking a fluid-filled cavity between its digestive canal and body wall, exemplified by flatworms.

Protostome

A coelomate animal whose mouth develops directly from the blastopore (the first opening formed in the gastrula) during embryonic development.

Deuterostome

An animal whose anus develops from the blastopore of the gastrula, while the mouth develops secondarily from a separate opening later in development.

Cnidocyte

A specialized stinging cell found on the tentacles of cnidarians containing a capsule with a coiled, venomous stinging barb (nematocyst) used to capture prey and defend against predators.

Flame Cell

A bulb-shaped excretory cell enclosing a tuft of flickering cilia, functioning to flush water and metabolic waste through excretory tubules in flatworms.

Proglottid

One of the continually multiplying individual body sections of a tapeworm that contains complete male and female reproductive organs and mature fertilized eggs.

Hydrostatic Skeleton

A support structure consisting of fluid under pressure enclosed within a closed body space, providing rigid support against which muscles contract to produce movement.

Radula

A flexible, rasplike, toothed tonguelike band in mollusks used for scraping off algae, tearing plant tissue, or drilling into prey shells.

Mantle

A protective membrane fold of epidermal tissue covering the visceral mass of mollusks that secretes calcium carbonate to construct the shell.

Nephridium

A ciliated invertebrate tubular organ through which nitrogenous cellular wastes are collected from the body cavity and discharged to the exterior.

Ecological Importance of Annelids

The environmental roles played by segmented worms, including soil aeration and root facilitation by oligochaetes, organic carbon cycling by marine polychaetes, and therapeutic anticoagulant applications by leeches.

Clitellum

A thickened, glandular, non-segmented band on the body of adult earthworms that secretes a protective mucus cocoon in which embryos develop.

Cephalothorax

A distinct fused body tagma composed of the joined head and thorax regions, found in chelicerates and most decapod crustaceans.

Molting

The periodic biological shedding of the non-living outer chitinous exoskeleton by an arthropod to allow for physical bodily expansion.

Malpighian Tubules

Slender excretory tubules operating in terrestrial arthropods that extract metabolic wastes from the surrounding hemolymph and deposit them directly into the gut.

Tympanum

A specialized vibrating auditory membrane located on the legs, abdomen, or thorax of various insects utilized to perceive sound vibrations.

Pheromone

A chemical substance produced and secreted by an animal that alters or directs the behavioral and reproductive responses of other individuals of the same species.

Complete Metamorphosis

An insect developmental pattern consisting of four morphologically distinct phases: egg, voracious larva, non-feeding pupa inside a cocoon, and fully developed adult.

Incomplete Metamorphosis

An insect developmental process that advances through three stages: egg, wingless immature nymph that undergoes repetitive molts, and mature winged adult.

Caste

A specialized structural and functional class of individuals within a social insect colony, such as reproductive queens, sterile workers, or reproductive male drones.

Characteristics of Arthropod Groups

The taxonomic classifications dividing arthropods into crustaceans, arachnids, insects, and myriapods according to their body segmentation, number of antennae, and paired ambulatory appendages.

Insect Mouthpart Adaptations

The specialized morphological variations of insect feeding structures modified for distinct dietary roles, including siphoning, sponging, piercing-sucking, and chewing.