AP Biology unit 7

Oogenesis

Egg production

cleavage

a series of mitotic divisions whereby the enormous volume of egg cytoplasm is divided into numerous smaller, nucleated cells.

differentiation

process in which cells become specialized in structure and function

morphogenesis

The process by which an organism takes shape and the differentiated cells occupy their appropriate locations.

differential

gene expression results from genes being regulated differently in each cell type

Cytoplasmic determinants

Maternal substances in egg that influence the course of early development.

cytoplasmic determinants

As the zygote divides by mitosis, the resulting cells contain different ___ ___, which lead to different gene expression

induction

signal molecules from embryonic cells cause transcriptional changes in nearby target cells

morula, blastula

zygote--> ___ ---> ____

morula

solid ball of cells

blastula

hollow ball of cells

zygote

fertilized egg

gastrulation

In animal development, a series of cell and tissue movements in which the blastula stage embryo folds inward, producing a three layered embryo, the gastrula.

ectoderm, mesoderm, endoderm

the 3 cell layers that gastrulation establishes

ectoderm

outermost germ layer; produces sense organs, nerves, and outer layer of skin

mesoderm

middle germ layer; develops into muscles, and much of the circulatory, reproductive, and excretory systems

endoderm

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

neurulation

formation of notochord and neural tube, develop into backbone and brain and spinal cord

Organogenesis

organ formation that takes place during the first two months of prenatal development

Placenta

organ that nourishes the fetus

determination

The point during development at which a cell becomes committed to a particular fate due to cytoplasmic effects or to induction by neighboring cells.

epigenetics

the study of influences on gene expression that occur without a DNA change

gene

determination is at the ___ level

apoptosis

programmed cell death

pattern formation

The development of a spatial organization of tissues and organs.

Positional information

The molecular cues that control pattern formation, tells a cell its location relative to the body axes and to neighboring cells

homeotic genes

Genes that determine basic features of where a body part is.

maternal effect genes

encode cytoplasmic determinants that initially establish the axes of the body of Drosophila

egg polarity

maternal effect genes are also called _ ___ genes

Bicoid

'Two Tailed', a defect in an embryo that results in two posterior structures (two tails, no head)

morphogens

establish an embryo's axes and other features of its form

totipotent

Stem cells with the potential to differentiate into any type of cell.

nuclear transplantation

A technique in which the nucleus of one cell is placed into another cell that already has a nucleus or in which the nucleus has been previously destroyed.

enucleated

the condition where a cell does not contain a nucleus

stem cell

unspecialized cell that can give rise to one or more types of specialized cells

pluripotent

Cells that are capable of developing into most, but not all, of the body's cell types

acquired traits

Skills that you learn to do or develop during your life time

Charles darwin

English natural scientist who formulated a theory of evolution by natural selection (1809-1882)

selective breeding

The process of selecting a few organisms with desired traits to serve as parents of the next generation

charles darwin's ideas

natural selection: variation exists, overproduction of offsping, competition, differential survival and reproduction

natural selection

A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits.

variation

Any difference between individuals of the same species.

overproduction

organisms produce more offspring than can survive

competition

the struggle between organisms to survive in a habitat with limited resources

differential survival

the belief that only the organisms best adapted to existing conditions are able to survive and reproduce.

differential reproduction

Phenomenon in which individuals with adaptive genetic traits produce more living offspring than do individuals without such traits.

fossil record

information about past life, including the structure of organisms, supports transition species

anatomical record

homologous and vestigial structures, embryology and development

molecular record

comparing DNA and protein structure

artificial selection

Breeding organisms with specific traits in order to produce offspring with identical traits; human caused evolution

vestigial structures

remnant of a structure that may have had an important function in a species' ancestors, but has no clear function in the modern species.

homologous structures

Structures in different species that are similar because of common ancestry.

analogous structures

Body parts that share a common function, but not structure; no evolutionary relationship

convergent evolution

Process by which unrelated organisms independently evolve similarities when adapting to similar environments

parallel evolution

Two related species that have made similar evolutionary adaptations after their divergence from a common ancestor

vestigial organs

organ that serves no useful function in an organism

comparative embryology

the study of the similarities and differences in the embryos of different species

population

A group of individuals that belong to the same species and live in the same area

gene pool

collection of alleles in the population

allele frequency

Number of times that an allele occurs in a gene pool compared with the number of alleles in that pool for the same gene

genetic drift

A change in the allele frequency of a population as a result of chance events rather than natural selection

predation selection

acts on both predator and prey: behaviors, camouflage and mimicry, speed, defenses (physical and chemical)

physiological selection

Acting on body functions (disease resistance, protection from injury, etc.)

sexual selection

A form of natural selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates.

founder effect

change in allele frequencies as a result of the migration of a small subgroup of a population

bottleneck

process in which a large population declines in number, then rebounds but with a limited gene pools

founder effect and bottleneck

two examples of genetic drift

founder effect

the ___ ___ skews the gene pool of the new population

industrial melanism

darkening of populations of organisms over time in response to industrial pollution

allopatric isolation

The process of speciation that occurs in geographic isolation

sympatric isolation

two subpopulations become reproductively isolated within the same geographic area

allopatric speciation

The formation of new species in populations that are geographically isolated from one another.

ecological isolation

species occur in the same area, but they occupy different habitats and rarely encounter each other

mechanical isolation

Morphological differences can prevent successful mating

gametic isolation

Sperm of one species may not be able to fertilize eggs of another species

hybrid breakdown

Hybrid is fertile, but when they breed the next generation is sterile.

gradualism

The theory that evolution occurs slowly but steadily

Punctuated Equilibrium

Pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change

stromatolites

Oldest known fossils formed from many layers of bacteria and sediment.

endosymbiosis

A theorized process in which early eukaryotic cells were formed from simpler prokaryotes.

cleavage

cytoplasmic determinants

morula

blastula

gastrulation