Terms and Definitions

AP Bio; Summer Work

Biology

The scientific study of life.

Emergent properties

New properties that appear at each level of biological organization arising from the arrangement and interaction of parts rather than from the parts themselves.

Reductionism

Studying a complex system by breaking it down into simpler and more manageable components.

Systems biology

Studying a biological system by analyzing the interactions among all of its parts as a whole.

Structure and function

The theme that a biological structure's form is correlated with what it does so knowing one gives clues about the other.

Cell

The lowest level of biological organization that can perform all activities required for life.

Prokaryotic cell

A cell that lacks a nucleus and other membrane-enclosed organelles and is generally smaller than a eukaryotic cell.

Eukaryotic cell

A cell containing a nucleus and other membrane-enclosed organelles.

DNA (deoxyribonucleic acid)

The molecule that carries genetic information made of two strands of nucleotides in a double helix.

Nucleotide

A chemical building block of DNA abbreviated as A or T or C or G.

Chromosome

A structure containing one very long DNA molecule with hundreds or thousands of genes along it.

Gene

A stretch of DNA along a chromosome that serves as the unit of inheritance passed from parents to offspring.

Gene expression

The process in which information in a gene directs the manufacture of a cellular product as DNA is transcribed into RNA which is translated into a protein.

Genome

The entire library of genetic instructions an organism inherits.

Genomics

The study of whole sets of genes in one or more species rather than one gene at a time.

Bioinformatics

The use of computational tools to store and organize and analyze the huge volume of biological data from high-throughput methods.

Producer

An organism such as a plant that converts light energy into chemical energy stored in sugars.

Consumer

An organism that gets energy by eating producers or other consumers.

Energy flow

The one-way movement of energy through an ecosystem entering as light and exiting as heat.

Chemical cycling

The repeated reuse of chemical elements within an ecosystem moving between organisms and the environment.

Biosphere

All life on Earth and all the places where life exists.

Ecosystem

All living things in a particular area plus the nonliving components of the environment they interact with.

Community

All the organisms of all species inhabiting a particular ecosystem.

Population

All the individuals of a single species living within the bounds of a specified area.

Organism

An individual living thing.

Organ system

A team of organs that work together to carry out a larger function.

Organ

A body part made of multiple tissues that carries out a particular function.

Tissue

A group of cells that work together performing a specialized function.

Organelle

A functional component within a cell.

Molecule

A chemical structure consisting of two or more atoms joined together.

Taxonomy

The branch of biology that names and classifies species into groups of increasing breadth.

Species

A group of similar organisms that can interbreed and the narrowest level of biological classification.

Genus

A group of closely related species.

Domain

The broadest level of biological classification of which there are three.

Bacteria

One of two prokaryotic domains containing the most diverse and widespread prokaryotes.

Archaea

One of two prokaryotic domains whose members often live in extreme environments such as salty lakes and hot springs.

Eukarya

The domain containing all organisms made of eukaryotic cells including plants and fungi and animals and protists.

Kingdom Plantae

The kingdom of multicellular eukaryotes that produce their own sugars through photosynthesis.

Kingdom Fungi

The kingdom of eukaryotes that absorb dissolved nutrients from outside their bodies.

Kingdom Animalia

The kingdom of multicellular eukaryotes that ingest other organisms and digest them internally.

Protists

Mostly single-celled eukaryotes that do not fit neatly into the three eukaryotic kingdoms and whose classification is still debated.

Unity

The underlying similarity shared by all living things explained by descent from common ancestors.

Diversity

The vast variety of life forms on Earth explained by natural selection modifying inherited traits in different environments.

Charles Darwin

The naturalist who published On the Origin of Species in 1859 proposing descent with modification and natural selection.

On the Origin of Species

Darwin's 1859 book arguing that species arose by descent with modification and that natural selection is the mechanism.

Descent with modification

Darwin's phrase for the idea that species arose from a succession of ancestors that differed from them where unity comes from the descent and diversity from the modification.

Natural selection

The process in which individuals with inherited traits better suited to their environment survive and reproduce more than others so those traits become more common over generations.

Adaptation

An inherited trait produced by natural selection that makes an organism better suited to its environment.

Common ancestor

An ancestral species from which two or more later species descended and which is represented by a branch point on an evolutionary tree.

Tree of life

A branching diagram showing evolutionary relationships in which each branch point marks a common ancestor.

Geographic isolation

Separation of populations by physical barriers that prevents interbreeding and allows them to diverge into separate species.

Science

A way of knowing that aims to understand the natural world.

Inquiry

A search for information and explanations of natural phenomena covering the whole cycle of observing and forming hypotheses and testing them.

Observation

The use of the senses sometimes aided by tools to gather information about the world.

Data

Recorded observations that serve as the items of information on which scientific inquiry is based.

Qualitative data

Data recorded as descriptions rather than numerical measurements.

Quantitative data

Data expressed as numerical measurements often organized into tables or graphs.

Inductive reasoning

Deriving a general conclusion from a large number of specific observations.

Deductive reasoning

Logic that flows from the general to the specific by using a general premise to predict what results should occur in a specific case.

Hypothesis

A tentative and testable answer to a well-framed question that is based on available data and formed by inductive reasoning.

Falsifiable

Capable of being shown to be false by some possible observation or experiment which is a requirement for any scientific hypothesis.

Prediction

The specific result expected if a hypothesis is correct derived by deductive reasoning and stated in if-then form.

Controlled experiment

An experiment designed to compare an experimental group with a control group that ideally differs in only the one factor being tested.

Control group

The group that does not receive the factor being tested and is used as a baseline for comparison.

Experimental group

The group that receives or experiences the one factor being tested.

Canceling out variables

The way researchers actually handle other variables in a controlled experiment by letting them affect both groups equally rather than eliminating them.

Scientific theory

An explanation much broader in scope than a hypothesis that generates many new testable hypotheses and is supported by a large body of evidence.

Technology

The application of scientific knowledge for a specific purpose usually affecting society.

Science as a social process

The idea that science is a communal endeavor with researchers checking and repeating and building on one another's work.

The hierarchy of levels of biological organization in living things.  

Biosphere → ecosystem → community → population → organism → organ system → organ → tissue → cell → organelle → molecule → atom.