How can we help?

You can also find more resources in our Help Center.

85 terms

Biology

STUDY
PLAY
meiosis
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
gametes
a haploid reproductive cell that unites with another haploid reproductive cell to form a zygote
haploid
describes a cell, nucleus, or organism that has only one set of un paired chromosomes
diploid
a cell that contains two haploid sets of chromosomes
allele
one of the alternative forms of a gene that governs a characteristic, such as hair color
co-dominance
a condition in which both alleles for a gene are fully expressed
phenotype
an organism's appearance or other detectable characteristics that results from the organism's genotype and the environment
heredity
the passing of genetic traits from parent to offspring
polygenenic
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
autosomes
any chromosome that is not a sex chromosome
F1
the first generation of offspring obtained from an experimental cross between two organisms
trait
a genetically determined characteristic
genotype
the entire genetic makeup of an organism; the combination of genes for one or more specific traits
hybrid
in biology, the offspring of a cross between parents that have differing traits; a cross between individuals of the same species, subspecies, or varieties
carrier
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
heterozygous
describes an individual that carries two different alleles of a gene
genetics
the science of heredity and of the mechanisms by which traits are passed from parent to offspring
recessive
in genetics, describes an allele that is expressed only when no dominant allele is present in an individual
purebred
the offspring of many generations that have the same traits
Punnett Square
a graphic used to predict the results of a genetic cross
probability
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
homozygous
describes an individual that has identical alleles for a trait on both homologous chromosomes
gene
the most basic physical unit of heredity; a segment of nucleic acids that codes for a functional unit of RNA and/or protein
dominant
in genetics, describes an allele that is fully expressed whenever the allele is present in an individual
nondisjunction
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
zygote
the cell that results from the fusion of gametes; fertilization of the egg
adaption
the process of becoming adapted to an environment;; an anatomical, physiological, or behavioral change that improves a population's ability to survive
speciation
the formation of new species as a result of evolution
species
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
biogeography
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
Darwin
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.
Pangaea
(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
chordates
an animal phylum that has a notochord, a dorsal hollow nerve cord, and gill slits at some time in its life cycle
reptiles
vertebrates that live on land, scales cover body, lay eggs, cold blooded
amphibians
vertebrates that live in water and on land, smooth skin covers body, lay eggs, cold blooded
mammals
warm-blooded vertebrate animals characterized by hair on the skin and, in females, mammary glands for nourishing the young
aves
Warm blooded; amniotic egg; wings; feathers; hollow bones; 4-chambered heart
fish
any of various mostly cold-blooded aquatic vertebrates usually having scales and breathing through gills
primates
an animal order including lemurs and tarsiers and monkeys and apes and human beings
mollusk
invertebrate having a soft unsegmented body usually enclosed in a shell
sponges
are aquatic animals that make up the phylum porifera
echinodermata
radially symmetrical marine invertebrates including e.g. starfish and sea urchins and sea cucumbers
cnidaria
Two-cell layered body with a digestive cavity surrounded by tentacles that sting prey. E.g. jellyfish, hydras, sea anemones.
arthropods
A group of organisms that have jointed appendages, an exoskeleton, bilateral symmetry, and reproduce sexually; insects, arachnids, millipedes and cenitpedes, and crustaceans
pistil
the female reproductive part of a flower that produces seeds and consists of an ovary, style, and a stigma
stigma
the apical end of the style where deposited pollen enters the pistil
style
(botany) the narrow elongated part of the pistil between the ovary and the stigma
ovary
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
stamen
the male reproductive structure of a flower that produces pollen and consists of an anther at the tip of the filament
anther
in flowering plants, the tip of a stamen, which contains the pollen sacs where grains form
filament
stalk that supports the anther
seeds
a plant embryo that is enclosed in a protective coat
fruit
a mature plant ovary; the plant organ in which the seeds are enclosed
photosynthesis
the process by which plants, algae, and some bacteria use sunlight, carbon dioxide, and water t produce carbohydrates and oxygen
flowers
the reproductive structure of a flowering plant that usually consists of a pistil, stamens, petals, and sepals
flower garden
a garden featuring flowering plants
watershed
a ridge of land that separates two adjacent river systems
ectoderm
the outer germ layer that develops into skin and nervous tissue
endoderm
the inner germ layer that develops into the lining of the digestive and respiratory systems
arboreal
relating to or resembling a tree or trees
mammal types
placental, marsupial, monotreme
placental
has placenta
marsupial
pouch
monotreme
lay eggs (platypus)