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the process in cell division during which the number of chromosomes decreases to half the original number by two divisions of the nucleus, which results in this production of sex cells


a haploid reproductive cell that unites with another haploid reproductive cell to form a zygote


describes a cell, nucleus, or organism that has only one set of un paired chromosomes


a cell that contains two haploid sets of chromosomes


one of the alternative forms of a gene that governs a characteristic, such as hair color


a condition in which both alleles for a gene are fully expressed


an organism's appearance or other detectable characteristics that results from the organism's genotype and the environment


the passing of genetic traits from parent to offspring


a character that is influenced by more than one gene

x chromosome

the sex chromosome that is present in both sexes: singly in males and doubly in females


any chromosome that is not a sex chromosome


the first generation of offspring obtained from an experimental cross between two organisms


a genetically determined characteristic


the entire genetic makeup of an organism; the combination of genes for one or more specific traits


in biology, the offspring of a cross between parents that have differing traits; a cross between individuals of the same species, subspecies, or varieties


in biology, an individual who has one copy of a recessive autosomal allele that causes disease in the homozygous condition

y chromosomes

the sex chromosome found only in males

sex chromosomes

one pair of chromosomes that determine the sex of the individual


describes an individual that carries two different alleles of a gene


the science of heredity and of the mechanisms by which traits are passed from parent to offspring


in genetics, describes an allele that is expressed only when no dominant allele is present in an individual


the offspring of many generations that have the same traits

Punnett Square

a graphic used to predict the results of a genetic cross


the likelihood that a possible future event will occur in any give instance of the event; the mathematical ratio of the number of times one outcome of any is likely to occur to the number of possible outcomes of the event

incomplete dominance

a condition in which a trait in an individual is intermediate between the phenotype of the individual's two parents because the dominant allele is unable to express itself fully


describes an individual that has identical alleles for a trait on both homologous chromosomes


the most basic physical unit of heredity; a segment of nucleic acids that codes for a functional unit of RNA and/or protein


in genetics, describes an allele that is fully expressed whenever the allele is present in an individual


the failure of homologous chromosomes to separate during meiosis 1 or the failure of sister chromatids to separate during mitosis or meiosis 2

sex linkage

an association between genes in sex chromosomes that makes some characteristics appear more frequently in one sex than in the other


the cell that results from the fusion of gametes; fertilization of the egg


the process of becoming adapted to an environment;; an anatomical, physiological, or behavioral change that improves a population's ability to survive


the formation of new species as a result of evolution


a group of organisms that are closely related and can mate to produce fertile offspring

artificial selection

the human practice of breeding animals or plants that have certain desired traits

natural selection

the process by which individuals that are better adapted to their environment survive and reproduce more successfully than less well adapted individuals do; a theory to explain the mechanism of evolution


the study of the geographical distribution of living organisms and fossils on Earth

homologous structures

describes a character that is shared by a group of species because it is inherited from a common ancestor

Jean Baptiste Lamarck

This man developed the first cohesive theory of evolution after his studies of biology

acquired characteristics

Characteristics of an organism gained during its lifetime, not determined genetically and therefore not transmitted to the offspring

pre-zygotic mechanisms

these mechanisms prevent mating between individuals of different species OR they prevent fertilization from occuring if mating does take place

post-zygotic mechanisms

Prevent zygote from developing into fertile adult


an English scientist who came up with the theory of natural selection

binomial nomenclature

Classification system in which each species is assigned a two-part scientific name

taxon categories

species, genus, family, order, class, phylum, kingdom

Linnaeus and classification

in this system of classification, organisms are grouped at successive levels of a hierarchy based on similarities in their form and structure

Australopithecus afarensis

Lucy; "southern" ape, 3.2 MYA, brain capacity: 515cc, found in Afar Valley, petite type

Homo habilis

extinct species of upright east African hominid having some advanced humanlike characteristics

Homo erectus

extinct species of primitive hominid with upright stature but small brain

Homo Neanderthals

lived in Europe, thick boned, larger brained, buried dead, made hunting tools

Homo sapiens

A species of the creatures Hominid who have larger brains and to which humans belong, dependent of language and usage of tools.


(plate tectonics) a hypothetical continent including all the landmass of the earth prior to the Triassic period when it split into Laurasia and Gondwanaland

Galapagos Island

Place where a lot of info was found. info, such as the finches who had different beaks, but were thought to be of the same ancestor


an animal phylum that has a notochord, a dorsal hollow nerve cord, and gill slits at some time in its life cycle


vertebrates that live on land, scales cover body, lay eggs, cold blooded


vertebrates that live in water and on land, smooth skin covers body, lay eggs, cold blooded


warm-blooded vertebrate animals characterized by hair on the skin and, in females, mammary glands for nourishing the young


Warm blooded; amniotic egg; wings; feathers; hollow bones; 4-chambered heart


any of various mostly cold-blooded aquatic vertebrates usually having scales and breathing through gills


an animal order including lemurs and tarsiers and monkeys and apes and human beings


invertebrate having a soft unsegmented body usually enclosed in a shell


are aquatic animals that make up the phylum porifera


radially symmetrical marine invertebrates including e.g. starfish and sea urchins and sea cucumbers


Two-cell layered body with a digestive cavity surrounded by tentacles that sting prey. E.g. jellyfish, hydras, sea anemones.


A group of organisms that have jointed appendages, an exoskeleton, bilateral symmetry, and reproduce sexually; insects, arachnids, millipedes and cenitpedes, and crustaceans


the female reproductive part of a flower that produces seeds and consists of an ovary, style, and a stigma


the apical end of the style where deposited pollen enters the pistil


(botany) the narrow elongated part of the pistil between the ovary and the stigma


in plants, a flower structure that contains one or more ovules from which female gametophytes are produced; in animals, the female gonad that produces eggs


the male reproductive structure of a flower that produces pollen and consists of an anther at the tip of the filament


in flowering plants, the tip of a stamen, which contains the pollen sacs where grains form


stalk that supports the anther


a plant embryo that is enclosed in a protective coat


a mature plant ovary; the plant organ in which the seeds are enclosed


the process by which plants, algae, and some bacteria use sunlight, carbon dioxide, and water t produce carbohydrates and oxygen


the reproductive structure of a flowering plant that usually consists of a pistil, stamens, petals, and sepals

flower garden

a garden featuring flowering plants


a ridge of land that separates two adjacent river systems


the outer germ layer that develops into skin and nervous tissue


the inner germ layer that develops into the lining of the digestive and respiratory systems


relating to or resembling a tree or trees

mammal types

placental, marsupial, monotreme


has placenta




lay eggs (platypus)

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