Biology Vocabulary
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Biology Vocabulary
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Biology Vocabulary
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Biology Vocabulary
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Biology Vocabulary
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Biology Vocabulary
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Biology Vocabulary
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Science
 An
organized way of using
evidence to learn about the
natural world.
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Observation
 The
process of gathering
information about events or
processes in a careful,
orderly way.
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Data
 The
information gathered
from observations.
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Inference
A
logical interpretation
based on prior knowledge or
experience.
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Hypothesis
 Proposed
solution to a
scientific problem.
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Spontaneous Generation
 The
idea that life can arise
from nonliving matter.
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Control
 An
experiment run without
a variable in order to show
that any data from the
experimental setup was due
only to the variable that was
being tested.
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Manipulated Variable
A
variable that is
deliberately changed.
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Responding Variable
 The
variable that is
observed and that changes
in response to the
manipulated variable.
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Theory
A
hypothesis that has been
tested over a period of time
that scientists consider it
true.
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Biology
 The
science that seeks to
understand the living world.
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Cell
 The
basic unit of structure
and function of living things.
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Sexual Reproduction
 Cells
from two different
parents unite to produce the
first cell of the new
organism.
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Asexual Reproduction
A
new organism is formed
from one parent and is
identical to the parent.
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Metabolism
 The
combination of
chemical reactions through
which an organism builds up
or breaks down materials as
it carries out its life
processes.
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Stimulus
A
signal to which an
organism responds.
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Homeostasis
 Most
organisms must keep
internal conditions such as
temperature and water
content fairly constant to
survive.
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Evolution
 The
ability of a group of
organisms to change over
time to increase their
chances of survival.
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Metric System
A
decimal system of
measurement whose units
are based on certain
physical standards and are
scaled on multiples of ten.
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Microscope
A
device that produces
magnified images of
structures that are too small
to see with with the unaided
eye.
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Compound Light Microscope
A
device used for
magnification that allows
light to pass through the
specimen and uses two
lenses to form an image.
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Electron Microscope
 Magnifying
device that uses
beams of electrons to
produce images
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Cell Culture
A
group of cells produced
from a single original cell
placed in a dish containing
nutrient solution.
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Cell Fractionation
 Technique
used to separate
the different cell parts.
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Atom
 Basic
unit of matter.
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Nucleus
 Center
of the atom that
contains the protons and
neutrons.
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Electron
 Negatively
charged particle
th
with 1/1840 the mass of a
proton.
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Element
A
pure substance that
consists entirely of one type
of atom.
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Isotopes
 Atoms
of the same element
that differ in the number of
neutrons they contain.
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Compound
A
substance formed by the
chemical combination of two
or more elements in definite
proportions.
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Ionic Bond
 Type
of bond formed when
one or more electrons are
transferred from one atom
to another.
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Ion
A
positively or negatively
charged atom.
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Covalent Bond
 Type
of bond formed when
two or more atoms share
electrons.
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Molecule
 The
structure that results
when atoms are joined
together by covalent bonds.
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van der Waals forces
 The
slight attraction
between molecules when
oppositely charged regions
come in close contact.
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Cohesion
 An
attraction between
molecules of the same
substance.
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Adhesion
 The
attraction between
molecules of different
substances.
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Solution
 Type
of mixture where one
substance is dissolved into
another and is evenly
distributed throughout.
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Solute
 The
substance that is
dissolved in a solution.
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Solvent
 The
substance in which the
solute dissolves.
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Suspensions
 Mixture
where the particles
of one substance are
suspended in another.
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pH Scale
A
measurement system to
indicate the concentration of
H+ ions in a solution.
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Acid
 Any compound that
+
H ions in solution.
forms
pH is
between zero and seven.
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Base
A
compound that produces
hydroxide (OH ) ions in
solution. Has a pH between
7 and 14.
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Buffers
 Weak
acids or bases that
can react with strong acids
or bases to prevent sharp
sudden changes in pH.
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Monomers
 Small
units which join
together to form polymers.
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Polymers
 Macromolecule
formed by
the joining of monomers.
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Carbohydrates
 Compounds
made up of
carbon, hydrogen and
oxygen atoms, usually in a
ratio of 1:2:1.
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Monosaccharides
 Single
sugar molecules.
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Polysaccharides
 Large
macromolecules
formed from
monosaccharides.
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Lipids
 Large
varied group of
biological molecules that are
generally not soluble in
water.
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Nucleic acids
 Macromolecules
containing
hydrogen, oxygen, nitrogen,
carbon & phosphorus.
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Nucleotides
 Monomers
consisting of
three parts: a 5-carbon
sugar, a phosphate group,
and a nitrogenous base.
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Ribonucleic acid (RNA)
 Single-stranded
nucleic acid
that contains the sugar
ribose. Important in the
production of proteins.
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Deoxyribonucleic acid (DNA)
 Nucleic
acid that contains
the sugar deoxyribose.
Contains hereditary
imformation.
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Proteins
 Macromolecules
that contain
nitrogen as well as carbon
hydrogen and oxygen.
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Amino Acids
 Compounds
with an amino
group (NH2) on one end and
a carboxyl group (COOH) on
the other end. Building
blocks of protein.
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Chemical Reaction
 Process
that changes, or
transforms, one set of
chemicals into another.
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Reactants
 The
elements or compounds
that enter into a chemical
reaction.
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Products
 The
elements or compounds
produced by a chemical
reaction.
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Activation Energy
 The
energy needed to get a
chemical reaction started.
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Catalyst
A
substance that speeds up
the rate of a chemical
reaction by lowering the
activation energy.
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Enzyme
 Proteins
that act as biological
catalysts.
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Ecology
 The
scientific study of
interactions among
organisms and their
environment.
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Biosphere
 The
combined portions of the
planet in which all of life
exists. Includes land, water &
atmosphere.
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Species
A
group of organisms so
similar to one another that
they can breed and produce
fertile offspring.
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Population
 Groups
of individuals that
belong to the same species
and live in the same area.
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Communities
 Assemblages
of different
populations that live
together in a defined area.
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Ecosystem
A
collection of all the
organisms that live in a
particular place together
with their nonliving
environment.
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Biome
A
group of ecosystems that
have the same climate and
similar dominant
communities.
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Autotrophs
 Organisms
that use energy
from the sun to make their
own food.
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Producers
 Organisms
that make their
own food and used by other
organisms for food.
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Photosynthesis
 The
process of using
sunlight, water and carbon
dioxide to make
carbohydrates and oxygen.
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Chemosynthesis
 Process
when organisms
use chemical energy to
make carbohydrates.
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Heterotrophs
 Organisms
that cannot
make their own food.
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Consumers
 Organisms
that cannot
make their own food so
they have to consume other
organisms.
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Herbivores
 Organisms
plants.
that eat only
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Carnivores
 Animals
that eat primarily
other animals.
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Omnivores
 Animals
that eat both plants
and animals.
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Detritivores
 Animals
that feed on the
remains of other animals or
plants.
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Decomposers
 Organisms
that break down
organic matter.
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Food Chain
A
series of steps in which
organisms transfer energy
by eating and being eaten.
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Food Web
 The
feeding relationships
among the various
organisms in an ecosystem
that form a network of
complex interactions.
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Trophic Level
 Each
step in a food chain or
food web.
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Ecological Pyramid
A
diagram that shows the
relative amounts of energy
or matter contained within
each trophic level in a food
chain or web.
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Biomass
 The
total amount of living
tissue within a given trophic
level.
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Biogeochemical Cycles
 The
flow of elements,
compounds and other forms
of matter are passed from
one organism to another or
recycled.
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Evaporation
 The
process by which water
is changed from a liquid to a
gas at the surface.
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Transpiration
 The
evaporation of water
through the leaves of
plants.
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Nutrients
 All
chemical substances that
an organism needs to
sustain life.
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Nitrogen Fixation
 Process
where bacteria that
live in the roots of certain
plants called legumes
convert nitrogen gas into
ammonia.
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Dentrification
 Process
where soil bacteria
convert nitrates into
nitrogen gas.
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Primary Productivity
 The
rate at which organic
matter is created by
producers.
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Limiting Nutrient
 When
an ecosystem is
limited by a single scare
nutrient.
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Algal Bloom
 When
an aquatic ecosystem
receives a large input of a
limiting nutrient like fertilizer
and over reproduces algae.
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Weather
 The
day to day condition of
Earth’s atmosphere at a
particular time and place.
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Climate
 The
average year after year
conditions of temperature
and precipitation in a
particular region.
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Greenhouse Effect
 The
natural situation in
which heat is retained by
the layer of greenhouse
gases.
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Polar Zones
 Cold
areas where the sun’s
rays strike the Earth at a
very low angle. Located
o
o
between 66.5 and 90
latitudes.
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Temperate Zones
 Climate
ranges from hot to
cold depending upon
season.
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Topical Zone
 Hot
climate between 23.5o
North and South latitudes.
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Biotic Factors
 The
biological influence on
organisms within an
ecosystem.
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Abiotic Factors
 Physical
or nonliving factors
that shape ecosystems.
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Habitat
 The
area where an
organism lives.
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Niche
 The
full range of physical
and biological conditions in
which an organism lives and
the way in which the
organism uses those
conditions.
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Resource
 Any
necessity of life such as
water, nutrients, light, food
or space.
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Competitive Exclusion Principal
 Principal
that states that no
two species can occupy the
same niche in the same
habitat at he same time.
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Predation
 An
interaction in which one
organism captures and
feeds on another organism.
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Symbiosis
 Any
relationship in which
two species live closely
together.
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Mutualism
A
relationship in which two
species both benefit from
each other.
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Commensalism
A
relationship where one
species benefits and the
other is neither ehlped nor
harmed.
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Electron-dot Diagram
 Diagram
that uses the
chemical symbol for an
element surrounded by a
series of dots to represent the
electron sharing that takes
place in a covalent bond.
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Parasitism
A
relationship in which one
organism lives in or on
another and harms it.
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Ecological Succession
 The
series of predictable
changes that occurs in a
community over time.
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Primary Succession
 Succession
that occurs on
land where no soil exists.
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Pioneer Species
 The
first species to populate
a new or damaged area.
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Secondary Succession
 Community
interactions that
tend to restore an
ecosystem after a
disturbance.
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Tolerance
 The
ability of a species to
survive and reproduce
under conditions that differ
from their optimal
conditions.
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Microclimate
 The
climate in a small area
that differs from the
surrounding climate.
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Canopy
 The
dense covering of leafy
tops of tall trees in the
tropical rain forest.
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Understory
 The
second level of shorter
trees that live in the shade
below the canopy.
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Deciduous
A
tree that sheds its leaves
during a particular season
each year.
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Coniferous
 Trees
that produce seeds in
cones and have evergreen
needles.
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Humus
 Material
formed in soils from
decaying leaves and other
organic matter.
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Tiaga
 Dense
evergreen forests of
coniferous trees.
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Permafrost
 Layer
of permanently frozen
subsoil.
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Plankton
 General
term for the tiny,
free floating organisms that
live in both freshwater and
saltwater.
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Phytoplankton
 Unicellular
algae.
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Zooplankton
 Unicellular
organisms.
animal-like
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Wetland
 An
ecosystem in which
water either covers the soil
or is present at or near the
surface for at least part of
the year.
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Estuaries
 Wetlands
formed where
rivers meet the sea.
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Detritus
 Tiny
pieces of organic
material that provide food
for organisms at the base of
the food web.
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Salt Marshes
 Temperate
zone estuaries
dominated by salt-tolerant
grasses above the low-tide
line and by seagrasses
under water.
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Mangrove Swamps
 Coastal
wetlands that are
widespread across tropical
regions where the dominant
species are salt tolerant
trees.
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Photic Zone
 Surface
layer of ocean
(200m) where there is
enough light for
photosynthesis.
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Aphotic Zone
 Zone
below 200m in the
ocean in which there is not
enough light for
photosynthesis to occur.
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Zonation
 The
prominent horizontal
banding of organisms that
live in a particular habitat.
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Coastal Ocean
 Extends
from the low-tide
mark to the outer edge of
the continental shelf.
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Kelp Forests
 Coastal
ocean community
named for giant brown
algae that can grow at
extraordinary rates.
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Coral Reefs
 Marine
ecosystem named
for small animals whose
hard, calcium carbonate
skeletons make up their
primary structure.
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Benthos
 Organisms
that live
attached or near the bottom
of the ocean.
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Cell Theory
 All
living things are made of
cells
 Cells are the basic unit of
structure and function
 New cells come from existing
cells.
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Nucleus
 Large
membrane enclosed
structure that contains cells
genetic material.
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Eukaryotes
 Cells
that contain nuclei.
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Prokaryotes
 Cells
that do not contain
nuclei.
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Organelles
 Specialized
the cell.
structures within
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Cytoplasm
 Jelly-like
substance within
the cell which provides
liquid environment.
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Nuclear Envelope
 Membranes
which surround
the nucleus and keep it
from mixing with the
cytoplasm.
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Chromotin
 Granular
material in the
nucleus made of DNA and
protein.
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Chromosomes
 Distinct
thread-like
structures that contain
genetic information
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Nucleolus
 Small
dense region in the
nucleus where the assembly
of ribosomes begins.
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Ribosome
 Organelles
proteins.
that produce
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Endoplasmic Reticulum
 Membrane
system where
ribosomes attach. Lipid
components assembled.
Tubular transportation
network within the cell.
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Golgi Apparatus
 Organelle
that modifies,
sorts and packages proteins
from the ER for storage and
secretion.
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Lysosomes
 Small
organelles filled with
enzymes that digest lipids,
carbohydrates and proteins.
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Vacuoles
 Organelles
that store water,
salts, proteins and
carbohydrates.
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Mitochondria
 Organelles
that convert the
chemical energy stored in
food into compounds that
are more convenient for the
cell to use (respiration).
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Chloroplasts
 Organelles
that capture
energy from the sun and
convert it into chemical
energy (photosynthesis).
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Cytoskeleton
 Network
of protein filaments
that helps the cell to
maintain its shape.
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Centrioles
 Structures
within animal
cells which help organize
the cell during division.
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Cell Membrane
 Thin
flexible barrier that
separates cells from each
other.
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Cell Wall
 Strong
supporting layer in
plant cells made of cellulose
which gives plants their rigid
strength.
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Lipid Bilayer
 Double
layered cell
membrane with hydrophobic
heads on the outside and
hydrophilic tails on the
inside.
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Concentration
 The
mass of solute in a
given volume of solution.
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Diffusion
 Passive
transport from an
area of high concentration
to an area of lower
concentration.
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Equilibrium
 Concentration
of solute is
balanced, or the same
throughout.
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Osmosis
 Diffusion
of water through a
selectively permeable
membrane.
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Isotonic
 When
two solutions have
the same concentration.
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Hypertonic
 Where
one solution has a
higher concentration than
another.
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Hypotonic
 When
one solution has a
lower concentration than
another.
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Facilitated Diffusion
 When
a cell membrane
protein helps the diffusion
of a substance through the
cell membrane.
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Active Transport
 Movement
of substances
into or out of the cell which
requires the cell to use
energy.
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Endocytosis
 The
process of taking
materials into a cell by folds
in the membrane.
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Phagocytosis
 Type
of endocytosis where
extensions of cytoplasm
surround a particle and
package it within a food
vacuole.
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Pinocytosis
 Cells
take up liquid from the
surrounding environment
and form tiny pockets along
the membrane pinch off and
form vacuoles.
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Exocytosis
 The
membrane of the
vacuole surrounding a
material within the cell fuses
with the cell membrane and
forces its contents out of
the cell.
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Cell Specialization
 Cells
throughout an
organism develop in
different ways to perform
different tasks.
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Tissue
 Similar
cells that work
together to perform a
particular function.
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Organ
A
group of tissues working
together to perform an
essential task.
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Organ System
A
group of organs working
together to perform a
specific function.
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Adenosine triphosphate ATP
 One
of the principal
chemical compounds that
living things use to store
and release energy.
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pigment
 Light-absorbing
molecule.
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chlorophyll
 Principal
pigment of plants
and other photosynthetic
organisms; captures light
energy.
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thylakoid
 Saclike
photosynthetic
membrane found in
chloroplasts.
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photosystem
 Light-collecting
chloroplast.
units of the
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stroma
 Opening
in the underside of
a leaf that allows carbon
dioxide and oxygen to
diffuse into and out of the
leaf.
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NADP+
 Nicotinamide
adenine
dinucleotide phosphate.
One of the carrier molecules
that transfers high-energy
electrons from chlorophyll to
other molecules.
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Light dependent reactions
 Reactions
of photosynthesis
that use energy from light
to produce ATP and NADPH.
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ATP synthase
 Large
protein that uses
+
energy from H ions to bind
ADP and a phosphate group
together to produce ATP.
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Calvin cycle
 Reactions
of photosynthesis
in which energy from ATP
and NADPH is used to build
high-energy compounds
such as sugars.
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calorie
 Amount
of energy needed
to raise the temperature of
1 gram of water by 1
degree Celsius.
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glycolysis
 First
step in releasing the
energy of glucose, in which
a molecule of glucose is
broken into two molecules
of pyruvic acid.
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Cellular respiration
 Process
that releases energy
by breaking down glucose
and other food molecules in
the presence of oxygen.
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NAD+
 Nicotinamide
adenine
dinucleotide. Electron
carrier involved in glycolysis.
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fermentation
 Process
by which cells
release energy in the
absence of oxygen. Used to
produce alcoholic
beverages.
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anaerobic
 Process
that does not
require oxygen.
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aerobic
 Process
oxygen.
that requires
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Krebs cycle
 Second
stage of cellular
respiration, in which pyruvic
acid is broken down into
carbon dioxide in a series of
energy-extracting reactions.
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Electron transport chain
A
series of proteins in which
the high-energy electrons
from the Krebs cycle are
used to convert ADP into
ATP.
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Cell Division
 The
process by which a cell
divides into two new
daughter cells.
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Mitosis
 The
first stage of cell
division, division of the
nucleus.
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Cytokinesis
 The
second stage of cell
division, division of the
cytoplasm.
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Chromatids
 One
of two identical “sister”
parts of a duplicated
chromosome.
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Centromeres
 Area
where each pair of
chromatids is attached.
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Interphase
 “In-between”
period of
growth of a cell.
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Cell Cycle
 Series
of events that cells
go through as they grow
and divide.
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Prophase
 First
and longest phase of
mitosis (50-60%).
Chromosomes become
visible.
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Spindle
A
fanlike microtubule
structure that help separate
the chromosomes.
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Metaphase
 Second
phase of mitosis.
Chromosomes line up across
the center of the cell.
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Anaphase
 Third
phase of mitosis. The
centromeres that join the
sister chromatids split and
move to opposite sides
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Telophase
 Fourth
and final phase of
mitosis. The chromosomes
begin to disperse, nuclear
envelope reforms and
spindle breaks apart.
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Cyclin
 Protein
that regulates the
timing of the cell cycle in
eukaryotes.
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Cancer
A
disorder in which some of the
body’s own cells lose the ability to
control growth.
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Genetics
 The
scientific study of
heredity.
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Fertilization
 The
joining of male and
female reproductive cells
during sexual reproduction.
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True-breeding
 Producing
offspring having
the same traits as the
parents.
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Trait
A
specific characteristic such
as color or shape that varies
from one individual to
another.
Back
Hybrids
 The
offspring of parents
with different traits.
Back
Genes
 The
chemical factors that
determine traits.
Back
Alleles
 The
different forms of a
gene.
Back
Segregation
 Separation
of alleles during
gamete formation.
Back
Gametes
 Sex
cells which have half
the normal number of
chromosomes. Egg and
sperm.
Back
Probability
 The
likelihood that a
particular event will occur.
Back
Punnett Square
 Diagram
that shows the
possible gene combinations
that might result from a
genetic cross.
Back
Homozygous
 Organisms
that have two
identical alleles for a
particular trait. Can be
Dominant (TT) or recessive
(tt). True-breeding.
Back
Heterozygous
 Organisms
that have two
different alleles for the
same trait. (Tt) Hybrid
Back
Phenotype
 Outward
or physical
expression of genes.
Back
Genotype
 Genetic
makeup of an
organism.
Back
Independent Assortment
 Independent
segregation of
genes during the formation
of gametes.
Back
Incomplete dominance
 Heterozygous
phenotype is
somewhere between the
two homozygous
phenotypes. Ex. Red
flower X White = Pink
offspring.
Back
Codominance
 Both
alleles contribute to
the phenotype. Ex. Black
feathers X white = speckled.
Back
Multiple Alleles
 Three
or more alleles of the
same gene.
Back
Polygenic Traits
 Traits
controlled by the
interaction of several genes.
Back
Homologous
 Term
used to refer to
chromosomes that each
have a corresponding
chromosome from the
opposite-sex parent.
Back
Diploid
A
cell that contains both
sets of homologous
chromosomes.
Back
Haploid
 Gametes
of sexually
reproducing organisms
contain only a single set or
half the number of genes.
Back
Meiosis
 The
type of cell division
where the number of
chromosomes is halved to
produce sex cells.
Back
Tetrad
 Structure
containing four
chromatids that forms
during meiosis.
Back
Crossing-over
 As
homologous
chromosomes pair up and
form tetrads in meiosis they
exchange portions of their
chromatids.
Back
Gene Map
 Diagram
showing the
relative locations of each
known gene on a particular
chrmosome.
Back
Transformation
 Process
in which one strain
of bacteria is changed by a
gene or genes form another
strain of bacteria.
Back
Bacteriophage
A
type of virus that infects
bacteria.
Back
Base Pairing
 Principal
that bonds in DNA
can form only between
adenine and thymine and
between guanine and
cytosine.
Back
Histone
 Protein
molecule around
which DNA is tightly coiled
in chromatin.
Back
Replication
 DNA
molecule separates
into two strands, then
produces two new
complementary stands
following the rule of base
pairing.
Back
DNA Polymerase
 Enzyme
involved in DNA
replication that joins
individual nucleotides to
produce a DNA molecule.
Back
Messenger RNA
 Molecules
that contain
instructions for assembling
amino acids into proteins.
Back
Ribosomal RNA
 Type
of RNA that makes up
the major part of
ribosomes.
Back
Transfer RNA
 Type
of RNA molecule that
transfers amino acids to
ribosomes during protein
synthesis.
Back
Transcription
 Process
in which part of the
nucleotide sequence of DNA
is copied into a
complementary sequence in
RNA.
Back
RNA Polymerase
 Enzyme
similar to DNA
polymerase that binds to
DNA and separates the DNA
strands during transcription.
Back
Promoters
 Region
of DNA that
indicates to an enzyme
where to bind to make RNA.
Back
Introns
 Sequence
of DNA that is not
involved in coding for a
protein.
Back
Exons
 Expressed
sequence on
DNA, codes for a protein.
Back
Codon
 Three-nucleotide
sequence
on messenger RNA that
codes for a single amino
acid.
Back
Translation
 The
decoding of an mRNA
message into a polypeptide
chain (protein).
Back
Anticodon
 Group
of three bases on a
tRNA molecule that are
complementary to an mRNA
codon.
Back
Mutations
 Changes
is genetic material.
Back
Point Mutations
 Gene
mutations involving
changes in one or a few
nucleotides.
Back
Frameshift Mutations
 Mutation
that shifts the
“reading” frame of the
genetic message by
inserting or deleting a
nucleotide.
Back
Polyploidy
 The
condition in which an
organism has extra sets of
chromosomes.
Back
Operon
A
group of genes hat
operate together.
Back
Operator
 Region
of chromosome in
an operon to which the
repressor binds when the
operon is “turned off”.
Back
Differentiation
 Process
in which cells
become specialized in
structure and function.
Back
Hox Genes
 Series
of genes that controls
the differentiation of cells
and tissues in an embryo.
Back
Selective breeding
 Method
of breeding that
allows only those individual
organisms with desired
characteristics to produce
the next generation.
Back
hybridization
 Breeding
technique that
involves crossing dissimilar
individuals to bring together
the best traits of both
organisms.
Back
inbreeding
 Continued
breeding of
individuals with similar
characteristics to maintain
the desired characteristics
of a line of organisms.
Back
Genetic engineering
 Process
of making changes
in the DNA code of living
organisms.
Back
Restriction enzymes
 Enzyme
that cuts DNA at a
specific sequence of
nucleotides.
Back
Gel electrophoresis
 Procedure
used to separate
and analyze DNA fragments by
placing a mixture of DNA
fragments at one end of a
porous gel and applying an
electrical voltage to the gel.
Back
Recombinant DNA
 DNA
produced by
combining DNA from
different sources.
Back
Polymerase chain reaction (PCR)
 Technique
that allows
molecular biologists to make
many copies of a particular
gene.
Back
plasmid
 Small
circular piece of DNA
commonly found in some
types of bacteria and used
for genetic engineering.
Back
Genetic marker
 Gene
that makes it possible
to distinguish bacteria that
carry a plasmid with foreign
DNA form those that don’t.
Back
transgenic
 Term
used to refer to an
organism that contains
genes from other
organisms.
Back
clone
 Member
of a population of
genetically identical cells
produced from a single cell.
Back
karyotype
 Photograph
of
chromosomes grouped in
order in pairs.
Back
Sex chromosomes
 One
of two chromosomes
that determine an
individual's gender.
Back
autosome
 Chromosome
that is not a
sex chromosome.
Back
pedigree

Chart that shows the relationships within a
family.
Back
Sex-linked gene
 Gene
located on the X or Y
chromosome.
Back
nondisjunction
 Error
in meiosis in which
homologous chromosomes
fail to separate.
Back
DNA fingerprinting
 Analysis
of sections of DNA
that have little or no known
function, but vary widely
from one individual to
another, in order to identify
individuals
Back
Evolution
 Process
by which organisms
change over time.
Back
Fossils
 Preserved
remains of
ancient organsims.
Back
Artificial Selection
 Human
selection of traits
that they found useful.
Back
Struggle for Existence
 Members
of each species
compete regularly to obtain
food, living space and other
necessities of life.
Back
Fitness
 The
ability of an individual
to survive and reproduce in
its specific environment.
Back
Adaptation
 An
inherited characteristic
that increases an organism’s
chance of survival.
Back
Survival of the Fittest
or Natural Selection
 Individuals
with
characteristics that are
better suited to their
environment survive and
reproduce most
successfully.
Back
Common Descent
 Principal
that all living
things were derived form
common ancestors.
Back
Homologous Structures
 Structures
that have
different mature forms but
develop from the same
embryonic tissues.
Back
Vestigial Organs
 Organ
that serves no useful
function in an organism.
Back
Gene Pool
 All
of the genes, including
all the different alleles, that
are present in a population.
Back
Relative Frequency
 The
number of times that
an allele occurs in a gene
pool compared with the
number of time other alleles
for the same gene occur.
Back
Single-gene Trait
 Trait
controlled by a single
gene that has two alleles.
Back
Directional Selection
 When
individuals at one end
of the curve have higher
fitness than individual in the
middle or at the other end.
Back
Stabilizing Selection
 When
individuals near the
center of the curve have
higher fitness than
individuals at either end of
the curve.
Back
Disruptive Selection
 When
individuals at the
upper and lower ends of the
curve have higher fitness
than individuals near the
middle.
Back
Genetic Drift
 Random
change in allele
frequencies that occurs in
small populations.
Back
Founder Effect
A
situation in which allele
frequencies change as a
result of the migration of a
small subgroup of a
population.
Back
Hardy-Weinberg Principal
 Allele
frequencies in a
population will remain
constant unless one or more
factors cause those
frequencies to change.
Back
Genetic Equilibrium
 The
situation in which allele
frequencies remain
constant.
Back
Speciation
 Formation
of a new species.
Back
Reproductive Isolation
 Separation
of species of
populations so that they
cannot interbreed and
produce fertile offspring.
Back
Behavioral Isolation
 When
two populations are
capable of interbreeding but
have differences in
courtship rituals or other
reproductive strategies that
involve behavior.
Back
Geographic Isolation
 Two
populations are
separated by geographic
barrier such as rivers,
mountains, or bodies of
water.
Back
Temporal Isolation
 Two
or more species
reproduce at different times.
Back
paleontologist
 Scientist
who studies fossils.
Back
Fossil record
 Information
about past life,
including the structure of
organisms, what they are,
what ate them, in what
environment they lived, and
the order in which they lived.
Back
extinct
 Term
used to refer to a
species that has died out.
Back
Relative dating
 Method
of determining the
age of a fossil by comparing
its placement with that of
fossils in other layers of
rock.
Back
Index fossil
 Distinctive
fossil used to
compare the relative ages of
fossils.
Back
Half-life
 Length
of time required for
half of the radioactive atoms
in a sample to decay.
Back
Radioactive dating
 Technique
in which
scientists calculate the age
of a sample based on the
amount of remaining
radioactive isotopes it
contains.
Back
Geologic time scale
 Scale
used by
paleontologists to represent
evolutionary time.
Back
era
 One
of several subdivisions
of the time between the
Precambrian and the
present.
Back
period
 Unit
of time into which eras
are subdivided.
Back
Proteinoid microsphere
 Tiny
bubble, formed of large
organic molecules, that has
some characteristics of a
cell.
Back
microfossil
 Microscopic
fossil.
Back
Endosymbiotic theory
 Theory
that eukaryotic cells
formed from a symbiosis
among several different
prokaryotic organisms.
Back
Mass extinction
 Event
in which many types
of living things become
extinct at the same time.
Back
macroevolution
 Large-scale
evolutionary
changes that take place
over long periods of time.
Back
Adaptive radiation
 Process
by which a single
species or small group of
species evolves into several
different forms that live in
different ways; rapid growth in
the diversity of a group of
organisms.
Back
Convergent evolution
 Process
by which unrelated
organisms independently
evolve similarities when
adapting to similar
environments.
Back
coevolution
 Process
by which two
species evolve in response
to changes in each other.
Back
Punctuated equilibrium
 Pattern
of evolution in
which long stable periods
are interrupted by brief
periods of more rapid
change.
Back
Taxonomy
 Scientific
discipline in which
scientists classify organisms
and assign each organism a
universally accepted name.
Back
Binomial Nomenclature
 System
developed by
Carolus Linnaeus where
each species is assigned a
two-part scientific name.
Back
Genus
A
group of closely related
species. First part of
scientific name. Always
capitalized.
Back
Taxon
 Each
level in a naming
system.
Back
Family
 Group
of genera that share
many characteristics.
Back
Order
 Group
of similar families.
Back
Class
 Group
of similar orders.
Back
Phylum
 Group
of closely related
classes.
Back
Kingdom
 Large
taxonomic group,
consisting of closely related
phyla.
Back
Phylogeny
 Evolutionary
relationships
among organisms.
Back
Evolutionary Classification
 The
strategy of grouping
organisms together based
on their evolutionary
history.
Back
Derived Characters
 Characteristics
that appear
in recent parts of a lineage
but not in its older
members.
Back
Cladogram
A
diagram that show the
evolutionary relationships
among a group of
organisms
Back
Molecular Clock
A
model that uses DNA
comparisons to estimate the
length of time that two
species have been evolving
independently.
Back
Domain
 Most
inclusive taxonomic
category, larger than a
kingdom.
Back
Bacteria
 Domain
of unicellular
prokaryotic organisms that
have cell walls containing
peptidoglycan.
Back
Eubacteria
 Kingdom
of unicellular
prokaryotes whose cell walls
are made up of
peptidoglycan.
Back
Archaea
 Domain
of unicellular
prokaryotes that have cell
wall that do not contain
peptidoglycan.
Back
Archaebacteria
 Kingdom
of unicellular
prokaryotes whose cell walls
do not contain
peptidoglycan.
Back
Eukarya
 Domain
of all organisms
whose cells have nuclei,
including protists, plants,
fungi and animals.
Back
Protista
 Kingdom
composed of
eukaryotes that are not
classified as plants, animals,
or fungi.
Back
Fungi
 Kingdom
composed of
heterotrophs, many obtain
energy and nutrients from
dead organic matter.
Back
Plantae
 Kingdom
of multicellular
photosynthetic autotrophs
hat have cell walls
containing cellulose.
Back
Animalia
 Kingdom
of multicellular
eukaryotic heterotrophs
whose cells do not have cell
walls.
Back
Nervous system
 Organ
system of the body
that receives, interprets and
responds to the
environment. Organs
include brain, spinal cord
and nerves.
Back
Skeletal system
 Organ
system that is important in
movement, protection, mineral
storage and blood production.
Back
Muscular system
 Organ
system that is
important for motion and
heat production.
Back
Integumentary system
 Organ
system that protects
the body from outside
invaders and dehydration.
Includes the largest organ
of the body, the skin.
Back
Circulatory system
 Organ
system that
transports food, oxygen,
carbon dioxide and waste.
Organs include heart,
arteries, capillaries and
veins.
Back
Lymphatic system
 Organ
system that cleans
extracellular fluid and
returns it to the blood.
Back
Respiratory system
 Organ
system that
exchanges carbon dioxide
for oxygen in the alveoli.
Primary organs are the
lungs.
Back
Digestive system
 Organ
system that breaks
down food into simpler
substances that can be used
by the body. Organs
include stomach, small
intestine and large intestine.
Back
Excretory system
 Organ
system that removes
waste and toxins from the
blood. Primary organs are
the kidneys.
Back
Endocrine system
 Organ
system that uses
chemicals to regulate long
term and short term
activities. Organs include all
of the glands.
Back
Reproductive system
 Organ
system responsible
for producing offspring.
Major organs are the
ovaries and testis.
Back