adaptation
a trait that is found in most members of a species
allele
a different form of a gene
amino acid
a molecule that is the building block of proteins
antibody
a substance that the immune system produces to destroy pathogens
antigen
a protein on the surface of a pathogen
bacteria
a one-celled organism that has DNA
calorie
a measurement of energy
carrying capacity
the maximum population an ecosystem can support without losing resources
cell
the basic unit of life
cell cycle
the process of division of a cell into new identical cells
chemical reaction
a process in which the atoms of one or more substances rearrange and change
chromosome
a structure in a cell that contains DNA
codon
a combination of three bases
commensalism
a relationship that benefits one organism, while the other is neither harmed nor helped
common ancestor
an individual in a species history to which all individuals in that species can be traced
consumer
an organism that must eat other organisms to obtain energy
decomposer
an organism that feeds off the dead bodies of a once-living organism
DNA
a double-stranded substance that contains the genetic "blueprint" of an individual
dominant
an allele for which the phenotype will always be present
ecosystem
a community of living organisms and nonliving things that work together to make a balanced system
energy pyramid
a model of the energy flow through an ecosystem
enzyme
a large molecule that speeds up a chemical reaction
epigenome
chemical tag covering the genome
fermentation
the process of producing energy when there is not enough oxygen to break down sugar
food chain
a linear path within a food web
food web
a model of the feeding connections among species
gene
a segment of a chromosome that has codes for a particular trait
genome
an organism's entire set of DNA
genotype
the genetic makeup of an organism
homeostasis
the tendency of a system to achieve a relatively stable equilibrium
hormone
a chemical produced by the body that serves a regulatory role
host
an organism on which a parasite lives
immunization
a process in which the body receives a vaccine
infection
the presence of a pathogen in the body
invasive species
a plant or animal that is not native to an area and has a negative effect on that area
limiting factors
a factor that limits the size of a population
meiosis
a form of cell division by which a single cell divides into four daughter cells
metabolism
the sum of all chemical reactions that take place in an organism to maintain life
minerals
inorganic substances needed in trace amounts for growth and health
mitosis
a form of cell division by which a single cell divides into two identical cells
mutation
a change in DNA
mutualism
a relationship between two organisms in which both organisms benefit
natural selection
the process in which the individuals with beneficial traits survive
negative feedback
a reaction to change in a way that brings it back to its original state
organ
a substance in the body that is made of different tissues that work together to perform a specific function
organelle
smaller structure found within a cell
parasitism
a relationship that helps one organism while causing harm to the other
pathogen
an organism that can cause a disease in a living thing
phenotype
a form of a trait that is visible in an organism
photosynthesis
a process in plants that converts light energy to chemical energy
producer
an organism that capture the sun's energy and make their own food
protein
a long molecule used to build body tissues and send signals
Punnett Square
a diagram that shows the possible combinations of genotypes two parent organisms can produce
recessive
an allele for which the phenotype will be present only if the genotype is solely that allele
RNA
a single-stranded substance that carries cellular information
speciation
the process through which a group becomes two or more different species
symbiosis
any relationship between two organisms
system
a combination of organs and tissues that work together to perform a specific function
tissue
substance made of similar cells that work together to perform a specific activity
toxin
poison
transcription
the process of making an RNA copy of a DNA segment
translation
the process in which cells make proteins
trophic structure
the feeding relationship between organisms in an ecosystem
vaccine
a dead or inactive pathogen
variation
differences within individuals of a species
virus
a pathogen that can only reproduce inside the cell of a living thing
vitamin
organic substances needed in trace amounts for growth and health