Principles of Biology Exam 1 Terms

Characteristics of Life

its organized, it requires material and energy, it has the ability to reproduce and develop, it responds to its environment, it maintains an internal environment, and it has the capacity to adapt to its environment

Atom

smallest particle of an element that displays the properties of the element

Molecule

union of two or more atoms of the same element; also the smallest part of a compound that retains the properties of the compound

Cell

the smallest unit of life that displays all the properties of life; composed of cytoplasm surrounded by a plasma membrane

Tissue

a group of similar cells combined to perform a common function

Organ

combination of two or more different tissues performing a common function

Organ System

group of related organs working together; examples are the digestive and endocrine systems

Organism

level of biological organization that includes multiple organ systems; an individual of a species

Species

group of similarly constructed organisms capable of interbreeding and producing fertile offsprings; organisms that share a common gene pool; taxon at the lowest level of classification

Population

group of organisms of the same species occupying a certain area and sharing a common gene pool

Community

assemblage of species interacting with one another within the same environment

Ecosystem

the biological community together with the associated abiotic environment; characterized by a flow of energy and a cycling inorganic nutrients

Biosphere

zone of air, land, and water at the surface of the Earth, in which living organisms are found

Energy

capacity to do work and bring about change; occurs in a variety of forms

Metabolism

the sum of the chemical reactions that occur in a cell

Reproduction

the process of producing a new individual of the same kind

Development

process of regulated growth and differentiation of cells and tissuesGe

Genes

unit of heredity existing as alleles on the chromosomes, in diploid organisms, typically two alleles on the chromosomes, in diploid organisms, typically two alleles are inherited- one from each parent

DNA

nucleic acid polymer produced from covalent bonding of nucleotide monomers that contain the sugar deoxyribose; the genetic material of living organisms

Mutations

change in the nucleotide structure of an organisms DNA

Behavior

observable, coordinated responses to environmental stimuli

Homeostasis

maintenance of normal internal conditions in a cell or an organism by means of self-regulating mechanisms

Adaptations

species’ modification in structure, function, or behavior that makes a species more suitable to its environment

Natural Selection

mechanisms of evolutionary change caused by environmental selection of organisms most fit to reproduce; results in adaptation to the environment

Evolution

genetic change in a species over time, resulting in the development of genetic and phenotypic differences that are the basis of natural selection;descent of organisms from a common ancestor

Taxonomy

branch of biology concerned with identifying, describing, and naming organisms

Systematic

study of the diversity of life for the purpose of understanding the evolutionary relationships between speciesSpe

Species

group of similarly constructed organisms capable of interbreeding and producing fertile offspring; organisms that share a common gene pool

Genus

one of the categories, or taxa, used to group species; contains those species that are most closely related through evolution

Family

one of the categories, or taxa, used to group species; the taxon located above the genus level

Order

located above the family level

Class

taxon above the order level

Phylum

taxon above the class level

Kingdom

taxon above the phylum level

Supergroup

systematic term used to classify the major groups of eukaryotes based on DNA similarities

Domain

largest of the categories, or taxa, used to group species; the three domains of the Archaea, Bacteria, and Eukarya

Domain Archaea

1 of the 3 domains of life; contains prokaryotic cells that often live in extreme habitats and have unique genetic, biochemical, and physiological characteristics; its members are sometimes referreed to as archaeaD

Domain Bacteria

contains prokaryotic cells that differ from archaea because they have their own unique genetic, biochemical, and physiological characteristics

Domain Eukarya

consisting of organisms with eukaryotic cells; includes protists, fungi, plants, and animals

Prokaryote

organism that lacks a nucleus and the membrane-bound organelles typically found in eukaryotes

Eukaryotic Cell (eukaryote)

type of cell that has a membrane-bound nucleus and membranous organelles; found in organisms within the domain eukarya

Protists

the group of eukaryotic organisms that are not plants, fungus, or animal. Protists are generally a microscopic, complex single cell; they evolved before other types of Eukaryotes in the history of the Earth

Plants (kingdom plantae)

multicellular, photosynthetic eukaryotes that increasingly became adapted to live on land

Fungus (kigdom fungi)

eukaryotic saprotrophic decomposer; the body is made up of filaments called hyphae that form a mass called mycelium

Animal (kingdom animalia)

multicellular, heterotrophic eukaryote that undergoes development to achieve its final form. In general, animals are mobile organisms, characterized by the presence of muscular and nervous tissue

Scientific Method

process by which scientists formulate a hypothesis, gather data, by observation and experimentation, and come to a conclusion

Observation

initial step in the scientific method that often involves the recording of data from an experiment or natural event

Inductive Reasoning

using specific observations and the process of logic and reasoning to arrive at general scientific principles

Hypothesis

supposition established by reasoning after consideration of available evidence; it can be tested by obtaining more data, often by experimentation

Experiment

a test of a hypothesis that examines the influence of a single variable. Often involves both control and test groups

Deductive Reasoning

the use of general principles to predict specific outcomes. “if then”

Experimental Variable

factor of the experiment being tested

Responding Variable

result or change that occurs when an experimental variable is utilized in an experiment

Experimental Design

methodology by which an experiment will seek to support the hypothesis

Control Group

sample that goes through all steps of an experiment but does not contain the variable being tested, a standard against which the results of an experiment are checked

Model

simulation of a process that aids conceptual understanding until the process can be studied first hand; a hypothesis that described how a particular process could possibly be carried out

Data

facts or information collected through observation and/or experimentation

Technology

application of scientific information to solve or address a need of humans

Climate Change

recent changes in Earth’s climate; evidence suggests that this is primarily due to human influence, including the increased release of greenhouse gas

Global Warming

predicted increase in the Earth’s temperature due to human activities that promote the greenhouse effect

Biodiversity

total number of species, the variability of their genes, and their communities in which they live

Extinction

total disappearance of a species or higher group

Emerging Disease

disease, such as SARS or MERS, that has not previously been detected in humans

Matter

anything that takes up space and has mass

Elements

substances that cannot be broken down into substances with different properties; composed of only one type of atom

Atom

smallest particle of an element that displays the properties of the element P

Protons

positive subatomic particles located in the nucleus and assigned one atomic mass unit

Neutrons

neutral subatomic particles, located in the nucleus and assigned one atomic mass unit

Electrons

negative subatomic particles, moving about in an energy level around the nucleus of an atom

Electron Shell

the average location, or energy level, of an electron, in an atom. Often drawn as concentric circles around the nucleus

Atomic Number

number of protons within the nucleus of an atom

Mass Number

mass of an atom equal to the number of protons plus the number of neutrons within the nucleus

Isotopes

atoms of the same element having the same atomic number but a different mass number due to a variation in the number of neutrons

Atomic Mass

average of atom mass units for all the isotopes of an atom

Valence Shell

the outer electron shell of an atom contains the valence electrons, which determine the chemical reactivity of the atom

Octet Rule

the observation that an atom is most stable when its outer shell is complete and contains eight electrons; an exception is hydrogen, which requires only two electrons in its outer shell to have a completed shell

Molecule

union of two or more atoms of the same element; also, the smallest part of a compount that retains the properties of the compound

Compound

substance having two or more different elements in a fixed ratio

Ion

charged particle that carries a negative or positive charge

Ionic Bond

chemical bond in which ions are attracted to one another by opposite charges

Covalent Bond

chemical bond in which toms share one pair of electrons

Nonpolar Covalent Bonds

bond in which the sharing of electrons between atoms is fairly equal

Electronegativity

the ability of an atom to attract electrons toward itself in a chemical bond

Polar Covalent Bond

bond in which sharing of electrons between atoms is unequal

Hydrogen Bond

weak bond that arises between a slightly positive hydrogen atom of one molecule and a slightly negative atom of another molecule, or betwen parts of the same molecule

Calorie

amount of heat energy required to raise the temperature of one gram of water 1 degree celsius

Solution

fluid (the solvent) that contains a dissolved solid (the solute)

Solute

substance that is dissolved in a solvent, forming a new solution

Hydrophilic

type of molecule, often polar, that interacts with water by dissolving in water and/or by forming hydrogen bonds with water molecules

Hydrophobic

type of molecule that is typically nonpolar therefore does not interact easily with water

Cohesion

the ability of water molecules to cling to each other due to the processes of hydrogen bonding

Adhesion

the ability of water molecules to cling to, or be attracted to, a surface, such as a transport vessel in a plant or animal

Surface Tension

force that holds moist membranes together due to the attraction of water molecules through hydrgen bonds

Acid

molecules tending to raise the hydrogen ion concentration in a solution and thus to lower its pH numerically

Base

molecules tending to lower the hydrogen ion concentration in a solution and thus raise the pH numerically

pH Scale

measurement scale for hydrogen ion concentration

Buffer

substance or group of substances that tend to resist pH changes of a solution, thus stabilizing its relative acidity and basicity

Organic

molecule that always contains carbon and hydrogen, and often contains oxygen as well; organic molecules are associated with living organisms

Inorganic

molecules that do not contain carbon and hydrogen molecules together. examples include water, carbon, dioxide, and salts

Functional Group

specific clusters of atoms attached to the carbon skeleton of organic molecules that enters into reactions and behaves in a predictable way