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Biology

The study of life.

Biosphere

All of Earth's environments that support life.

Ecosystem

All living organisms and nonliving, physical things (ex: air, soil, water, sunlight) in a particular area and their interactions.

Community

Organisms in an ecosystem.

Population

Interacting group of individuals in a species.

Organism

An individual in a species.

Organ system

Several organs that work together to perform a certain function.

Organ

A collection of tissues that carry out a specialized function of the body.

Cell

A unit of living matter separated from its environment by a membrane. It is the lowest level of structure that can perform all activities required for life.

Organelle

A structure that performs a specific function in a cell.

Molecule

Two or more atoms held together by a covalent bond.

Atom

The smallest particle of matter.

Producers

Organisms that produce their own food (ex: plants). They use photosynthesis to trap the sun's energy, use carbon dioxide from the air and water from soil to make sugar molecules, and also get mineral nutrients from the soil.

Consumers

Organisms that obtains energy and nutrients by feeding on other organisms or their remains (ex: animals). They take in oxygen from the air and return carbon dioxide. Their waste returns chemicals to the soil.

Decomposers

Organisms that decompose the remains of dead organisms and change them to chemical nutrients for plants (ex: bacteria, fungi, worms).

A cell can…

… regulate its internal environment.

… take in and use energy.

… respond to its surroundings.

… develop and maintain organization.

… reproduce.

Emergent properties

New properties that emerge with each step up on the hierarchy of life, thanks to the arrangement and interaction of parts as complexity increases.

System

A combination of components.

Eukaryotic cells

The larger and more complex of the two types of cells, with a nucleus and membrane-bound organelles.

Prokaryotic cells

Smaller and more simple cells that lack a nucleus and most organelles.

DNA

Two long chains in a double helix made of four kinds of chemical building blocks found in a cell's nucleus; the genetic material that carries information about an organism and is passed from parent to offspring.

Properties common to all organisms

1) Order

2) Regulation of internal environment

3) Growth and development from inherited genes

4) Energy utilization

5) Response to environment

6) Reproduction

7) Evolution

Taxonomy

The branch of biology that names and classifies species.

Domain

The largest taxonomic group. There are three of them: Bacteria (prokaryotes), Archaea (also prokaryotes), and Eukarya (eukaryotes).

Kingdom

The second largest taxonomic group. There are six of them: Animalia (ingest food, are motile, and do not have rigid cell walls), Plantae (get food through photosynthesis and have cells with rigid cellulose walls), Protista, Eubacteria, Archaebacteria, and Fungi (decomposers who absorb nutrients).

Eukaryotes

Organisms with eukaryotic cells (cells that have a nucleus and many organelles).

Prokaryotes

Organisms with prokaryotic cells (simple cells that lack a nucleus and most organelles). They are unicellular, microscopic, and the most widespread of all organisms.

Protists

Single-celled and incredibly diverse organisms. Some, like algae, make their own food molecules through photosynthesis. Others (protozoans) eat other organisms. They were once exclusively classified in Kingdom Protista, but are now in multiple kingdoms.

"On the Origin of Species By Means of Natural Selection"

The first book of Charles Robert Darwin (a British biologist), published in November 1859. It presented evidence that evolution happens and offered a logical explanation of how it happens.

Theory

A widely accepted explanatory idea that is broad in scope and supported by large bodies of evidence.

Descent with modification

The process by which descendants of ancestral organisms spread into various habitats and accumulate adaptations to diverse ways of life.

Natural selection

This process occurs as heritable variations are exposed to environmental factors that favor the reproductive success of some individuals over others.

Inductive reasoning

Reasoning from detailed facts/large number of specific observations to general principles.

Hypothesis-based science

A scientific approach that explains nature through the proposing and testing of hypotheses.

Hypothesis

A tentative answer to some question; an explanation on trial. A good one leads to predictions that science can test by recording observations and designing experiments.

Deductive reasoning

The logic used in hypothesis-based science to come up with ways to test hypotheses. The reasoning flows from general premises to specific results (that you expect if true).

Properties of hypotheses

1) Testable

2) Falsifiable

3) Cannot be proven for certain

4) Gains credibility by surviving various attempts to falsify

Controlled experiment

An experiment designed to compare an experimental group with a control group. Ideally, the groups only differ in the one thing that the experiment is testing.

The goal of science

To understand natural phenomena.

The goal of technology

To apply scientific knowledge for a specific purpose.

Anion

a negative ion formed by gaining electrons

Atomic number

the number of protons in an atom

Cation

a positive ion formed by losing electrons

Chemical bond

an interaction between two or more of the same or different elements that results in the formation of molecules

Covalent bond

a type of strong bond between two or more of the same or different elements; forms when electrons are shared between elements

Electron

a negatively charged particle that resides outside of the nucleus in the electron orbital; lacks functional mass and has a charge of ?1

Electron transfer

the movement of electrons from one element to another

Element

one of 118 unique substances that cannot be broken down into smaller substances and retain the characteristic of that substance; each element has a specified number of protons and unique properties

Hydrogen bond

a weak bond between partially positively charged hydrogen atoms and partially negatively charged elements or molecules

Ion

an atom or compound that does not contain equal numbers of protons and electrons, and therefore has a net charge

Ionic bond

a chemical bond that forms between ions of opposite charges

Isotope

one or more forms of an element that have different numbers of neutrons

Mass number

the number of protons plus neutrons in an atom

Matter

anything that has mass and occupies space

Neutron

a particle with no charge that resides in the nucleus of an atom; has a mass of 1

Nonpolar covalent bond

a type of covalent bond that forms between atoms when electrons are shared equally between atoms, resulting in no regions with partial charges as in polar covalent bonds

Nucleus

(chemistry) the dense center of an atom made up of protons and (except in the case of a hydrogen atom) neutrons

Octet rule

states that the outermost shell of an element with a low atomic number can hold eight electrons

Periodic table of elements

an organizational chart of elements, indicating the atomic number and mass number of each element; also provides key information about the properties of elements

Polar covalent bond

a type of covalent bond in which electrons are pulled toward one atom and away from another, resulting in slightly positive and slightly negative charged regions of the molecule

Proton

a positively charged particle that resides in the nucleus of an atom; has a mass of 1 and a charge of +1

Radioactive isotope

an isotope that spontaneously emits particles or energy to form a more stable element

Van der Waals interaction

a weak attraction or interaction between molecules caused by slightly positively charged or slightly negatively charged atoms

Acid

a substance that donates hydrogen ions and therefore lowers ph

Adhesion

the attraction between water molecules and molecules of a different substance

Base

a substance that absorbs hydrogen ions and therefore raises ph

Buffer

a solution that resists a change in ph by absorbing or releasing hydrogen or hydroxide ions

Cohesion

the intermolecular forces between water molecules caused by the polar nature of water; creates surface tension

Evaporation

the release of water molecules from liquid water to form water vapor

Hydrophilic

describes a substance that dissolves in water; water-loving

Hydrophobic

describes a substance that does not dissolve in water; water-fearing

Litmus paper

filter paper that has been treated with a natural water-soluble dye so it can be used as a ph indicator

Ph scale

a scale ranging from 0 to 14 that measures the approximate concentration of hydrogen ions of a substance

Solvent

a substance capable of dissolving another substance

Surface tension

the cohesive force at the surface of a body of liquid that prevents the molecules from separating

Temperature

a measure of molecular motion

Amino acid

a monomer of a protein

Carbohydrate

a biological macromolecule in which the ratio of carbon to hydrogen to oxygen is 1:2:1; carbohydrates serve as energy sources and structural support in cells

Cellulose

a polysaccharide that makes up the cell walls of plants and provides structural support to the cell

Chitin

a type of carbohydrate that forms the outer skeleton of arthropods, such as insects and crustaceans, and the cell walls of fungi

Denaturation

the loss of shape in a protein as a result of changes in temperature, ph, or exposure to chemicals

Deoxyribonucleic acid (DNA)

a double-stranded polymer of nucleotides that carries the hereditary information of the cell

Disaccharide

two sugar monomers that are linked together by a peptide bond

Enzyme

a catalyst in a biochemical reaction that is usually a complex or conjugated protein

Fat

a lipid molecule composed of three fatty acids and a glycerol (triglyceride) that typically exists in a solid form at room temperature

Glycogen

a storage carbohydrate in animals

Hormone

a chemical signaling molecule, usually a protein or steroid, secreted by an endocrine gland or group of endocrine cells; acts to control or regulate specific physiological processes