Introduction to Biology and the Diversity of Life

Vocabulary flashcards covering the four principles of biology, characteristics of life, biodiversity, classification, and the diverse kingdoms of life including Prokaryotes, Protists, Animals, Plants, and Fungi.

Homeostasis

The process by which an organism keeps its internal environment stable, even when the outside environment changes; it literally means 'same and stable.'

Evolution

The change in species over time through natural selection, where organisms with helpful traits reproduce more, causing characteristics to change over generations.

Cell theory

A major principle stating that all living things are made of cells, cells are the basic unit of life, and all cells come from preexisting cells.

Gene theory

A principle stating that traits are controlled by genes, which are segments of DNA found on chromosomes and are passed from parents to offspring.

Stimulus

A change in the environment that causes a living thing to react, such as a frog jumping when disturbed.

Metabolism

The sum of all chemical reactions performed by a living thing, where food is converted into usable energy.

Biodiversity

The variety of living things and their processes, which includes genetic diversity, species diversity, and ecosystem diversity.

Biomimicry

Engineering that is inspired by nature, such as Velcro being inspired by plant burrs.

Ecosystem Services

Benefits provided by nature, such as plants producing oxygen, microorganisms purifying water, and insects pollinating crops.

Archaebacteria

One of the six kingdoms of life, consisting of prokaryotes that are often extremophiles like halophiles or hyperthermophiles.

Interdependence

The concept that no species can live alone and all organisms depend on their environment and other organisms for food, water, and shelter.

Symbiosis

A close relationship between organisms of different species where at least one organism benefits.

Mutualism

A type of symbiosis where both species benefit, such as the relationship between a sea anemone and a clownfish.

Commensalism

A type of symbiosis where one organism benefits and the other is unaffected, such as a whale and a barnacle.

Parasitism

A type of symbiosis where one organism benefits and the other is harmed, such as a dog and a tick.

Adaptation

A trait that helps an organism survive in its environment, necessary for competition and evolution.

Mass Extinction

The loss of $75\%$ or more species in a short geological time; scientists believe we are currently in a human-caused sixth mass extinction.

Phylogeny

The evolutionary history of a group of organisms, often represented using branching diagrams called phylogenetic trees.

Clade

A group that includes a common ancestor and all of its descendants.

Cladogram

A diagram showing the order of evolutionary branching based on shared traits, but not necessarily representing time or the amount of change.

Dichotomous key

A tool used to identify organisms by giving a series of two opposite choices that narrow down the identity step by step.

Taxonomy

The science of classifying organisms, helpfully organized into eight levels from Domain down to Species.

Binomial Nomenclature

A two-word scientific naming system (Genus species) that gives each species a unique name, such as Homo sapiens.

Prokaryotes

Single-celled organisms that lack a nucleus and membrane-bound organelles; include the domains Bacteria and Archaea.

Plasmids

Small extra loops of DNA found in prokaryotic cells.

Gram-Positive Bacteria

Bacteria characterized by a thick peptidoglycan cell wall that retains crystal violet stain.

Cyanobacteria

Photosynthetic bacteria that were instrumental in adding oxygen to early Earth.

Chemoheterotroph

The most common metabolic type of prokaryote, which uses organic chemicals for both energy and carbon sources.

Protists

A diverse group of eukaryotes in the Kingdom Protista that are not plants, animals, or fungi, and typically live in moist environments.

Pseudopods

Cytoplasm extensions also known as 'false feet' used by some protists for movement.

Phagocytosis

The process used by ingestive protists to engulf food.

Collagen

A protein used to hold multicellular animal cells together in the absence of cell walls.

Invertebrates

Animals without a backbone, making up approximately $95\%$ of all animal species.

Nonvascular Plants

Plants like mosses, liverworts, and hornworts that lack vascular tissue, grow low to the ground, and require moist habitats.

Gymnosperms

Seed plants that produce seeds in cones rather than flowers, such as conifers.

Angiosperms

The most diverse group of plants, characterized by flowers and seeds enclosed in ovaries that develop into fruit.

Chitin

The material that makes up the cell walls of fungi, distinguishing them from plants which use cellulose.

Mycelium

The body of a fungus, consisting of a network of thread-like filaments called hyphae.