any variation that makes an organism better suited to its environment.
study of embryos and their development.
change in inherited characteristics over time.
model describing evolution as a slow process by which one species changes into a new species through a continuing series of mutations and variations over time.
humanlike primate that appeared about 4 million to 6 million years ago, ate both plants and meat, and walked upright on two legs.
early humans that likely evolved from Cro-Magnons.
body parts that are similar in structure and origin and can be similar in function.
a process by which organisms with traits best suited to their environment are more likely to survive and reproduce; includes concepts of variation, overproduction, and competition.
group of mammals including humans, monkeys, and apes that share characteristics such as opposable thumbs, binocular vision, and flexible shoulders.
model describing the rapid evolution that occurs when mutation of a few genes results in a species suddenly changing into a new species.
element that gives off a steady amount of radiation as it slowly changes to a nonradioactive element.
a type of rock, such as limestone, that is most likely to contain fossils and is formed when layers of sand, silt, clay, or mud are cemented and compacted together or when minerals are deposited from a solution.
a group of organisms that share similar characteristics and can reproduce among themselves producing fertile offspring.
inherited trait that makes an individual different from other members of the same species and results form a mutation in the organism's genes.
structure, such as the human appendix, that doesn't seem to have a function and may once have functioned in the body of an ancestor.
an alternate form that a gene may have for a single trait; may be dominant or recessive.
describe a trait that covers over, or dominates, another form of that trait.
biological and chemical methods to change the arrangement of a gene's DNA to improve crop production, produce large volumes of medicine, and change how cells perform their normal functions.
the study of how traits are inherited through the actions of alleles.
the genetic makeup of an organism.
the passing of traits from parent to offspring.
describes an organism with two different alleles for a trait.
describes an organism with two alleles that are the same for a trait.
an offspring that was given different genetic information for a trait from each parent.
production of a phenotype that is intermediate between the two homozygous parents.
outward physical appearance and behavior of an organism as a result of its genotype.
occurs when a group of gene pairs acts together and produces a specific trait, such as human eye color, skin color, or height.
a tool to predict the probability of certain traits in offspring that shows the different ways alleles can combine.
describes a trait that is covered over, or dominated, by another form of that trait and seems to disapear.
an allele inherited on a sex chromosome and that can cause human genetic disorders such as color blindness and hemophilia.
a type of reproduction - fission, budding, and regeneration - in which a new organism is produced from one organism and has DNA identical to the organism.
structure in a cell's nucleus that contains hereditary material.
cell whose similar chromosomes occur in pairs.
deoxyribonucleic acid; the genetic material of all organisms; made up of two twisted strands of sugar - phosphate molecules and nitrogen bases.
haploid sex cell formed in the female reproductive organs.
in sexual reproduction, the joining of a sperm and egg.
section of DNA on a chromosome that contains instruction for making specific proteins.
cell that has half the number of chromosomes as body cells.
reproductive process that produces four haploid sex cells from one diploid cell and ensures offspring will have the same number of chromosomes as the parent organism.
cell processes in which the nucleus divides to form two nuclei identical to each other and identical to the original nucleus, in a series of steps (prophase, metaphase, anaphase, and telophase).
any permanent change in a gene or chromosome of a cell; may be beneficial, harmful, or have little effect on an organism.
ribonucleic acids; a type of nucleic acid that carries codes for making proteins from the nucleis to the ribosomes.
a type of reproduction in which two sex cells, usually an egg and a sperm, join together to form a zygote, which well develop into a new organism with a unique identity.
haploid sex cell formed in the male reproductive organs; in humans, male reproductive cells are produced in the testes.
new diploid cell formed when a sperm fertilizes an egg, will divide by mitosis and develop into a new organism.
energy-requiring process in which transport protiens bind with particles and move them through a cell membrane.
a type of passive transport in cells in which molecules move from areas where there are more of them to areas where there are fewer of them.
process by which a cell takes in a substance by surrounding it with the cell membrane.
a type of protien that regulates nearly all chemical reactions in cells; a type of protien that speeds up chemical reactions in the body without being changed or use up itself.
occurs when molecules of one substance are spread evenly throughout the other substance.
process by which vesicles release their contents outside the cell.
process by which oxygen-lacking cells and some one-celled organisms release small amounts of energy from glucose molecules and produce waste such as alcohol, carbon dioxide, and lactic acid.
compound, such as H20, that is made form elements other than carbon and whose atoms usually can be arranged in only one structure.
the total of all chemical reactions in an organism.
a combination of substances in which the individual susbtances do not change or combine chemically but instead retain their own individual properties; can be gases, solids, liquids, or any combination of them.
compounds that always contain hydrogen and carbon; carbohydrate, lipids, protiens, and nucleic acids are these and are found in living things.
a type of passive transport that occurs when water diffuses through a cell membrane.
movement of substances through a cell membrane without the use of cellular energy; includes diffusion, osmosis, and facilitated diffusion.
process by which plants and many other producers use light energy to produce a simple sugar from carbon dioxide and water and give off oxygen.
process by which producers and consumers release stored energy from food molecules; series of chemical reactions used to release energy stored in food molecules.
Protective outer covering of all cells that regulates the interaction between the cell and the environment.
States that all organisms are made up of one or more cells, the cell is the basic unit of life, and all cells come from other cells.
rigid structure that encloses, supports, and protects the cells of plants, algae, fungi, and most bacteria.
green, chlorophyll-containing, plant-cell organelle that uses light energy to produce sugar form carbon dioxide and water.
constantly moving gel-like mixture inside the cell membrane that contains heredity material and is the location of most of a cell's life processes.
cytoplasmic organelle that moves materials around in a cell and is made up of a complex series of folded membrane; can be rough (with attached ribosomes) or smooth (without attached ribosomes).
organelles that package cellular materials and transport them within the cell or out of the cell.
living cell in which a virus can actively multiply or in which a virus can hide until activated by environmental stimuli.
cell organelle that breaks down food and releases energy.
organelle that controls all the activites of a cell and contains hereditary material made of protiens and DNA.
structure, such as the heart, made up of different types of tissues that all work together.
structure in the cytoplasm of a eukaryotic cell that can act as a storage site, process energy, move materials, or manufacture substances.
small cytoplasmic structure on which cells make their own proteins.
group of similar cells that work together to do one job.
a strand of hereditary material surrounded by a protein coating that can infect and multiply in a host cell.
two-word naming system that gives all organisms their scientific name.
theory that living things come only from other living things.
smallest unit of an organism that can carry on life functions.
standard to which the outcome of a test is compared.
first word of the two-word scientific name used to identify a group of similar species.
regulation of an organism's internal, life-maintaining conditions.
prediction that can be tested.
first and largest category used to classify organisms.
statement about how things work in nature that seems to be true consistently.
any living thing.
evolutionary history of an organism; used today to group organisms into six kingdoms.
procedures used to solve problems and answer questions that can include stating the problem, gathering information, forming a hypothesis, testing the hypothesis with an experiment, analyzing data, and drawing conclusions.
idea that living things come from nonliving things.
explanation of things or events based on scientific knowledge resulting from many observations and experiments.
something in an experiment that can change.