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any region where precipitation flows into a single stream or river


Process that occurs when soils in arid areas are brought under cultivation through irrigation. In arid climates, water evaporates quickly off the ground surface, leaving salty residues that render the soil infertile.

how much of freshwater is used for agriculture


where does carbon cycling occur?

between the ocean and the atmosphere

nitrogen cycle

the circulation of nitrogen

sedimentary cycles combined with the hydologic cycle move what?

move most mineral through terrestrial and aquatic ecosystems

What at hydro carbons?

three gases that consist only of carbon and hydrogen (methane, ethane, and ethylene)

What caused the great dying

sudden spike of carbon dioxide in the atmosphere

What are molecules assmebled from?

cellular pools of sugars, fatty acids, amino acids, and nucleotides


individual subunits of a larger molecule


consist of three to millions of subunits

how many atoms can carbon covalently bond with?



class of proteins that cause metabolic reactions to proceed faster


split molecules at specific groups, then attach one -OH group with an H atom at the exposed sites

where is eukaryotic dna enclosed?


where is prokaryotic DNA concentrated?



small sacs bounded to membranes that divide the interior of eukaryotic cells into functional compartments

1. Organism consist of one or more cells
2. The cell is the smallest unit of organization that displays the properties of life
3. Continuity of life arises directly from the growth and division of single cells

Cell Theory

what are the only groups of prokaryotic cells?

archaens and bacteria

What is the cause of Turner syndrome

a girl is given only one x chromosome

what gene is associated specifically with males?


what are adenine and guanine?


what are thymine and cytosine?


What is the backbone of DN?


What is the inside of DNa consist of?


what does adenine pair with in DNA to RNA transfer?


what was thought to hold hereditary material befor DNA discovered?


what did Rosalind Franklin discover?

the structure and dimensions of DNA

Who was Rosalind Franklin neglected by?

Maurice Wilkins

What is somatic cell nuclear transfer?

when descendants of a stem cell, used for therapeutic cloning go on to differentiate into cell types of specific organs and tissues


link between the nucleotide sequence of nucleic acids and the amino acids sequence

Where is the correspondence between genes and proteins encoded?

In mRNA transcripts

What are codons?

triplets in which mRNAs bases are read, when docked at a ribosome.

What is the Ozone a buildup of?

Oxygen added to the atmosphere by autotrophs performing photosynthesis

Black people have more of this than white people


What does the Krebs Cycle consist of?

Enzymes break down pyruvate to carbon dioxide and water. These reactions may release many electrons and hydrogen atoms

This number results from meiosis reducing the parental chromosome number by half

haploid number

hom many chromosomes do humans have?


how many sex chromosomes do humans have?


how is spectral karyotyping done?

a range of dyes is used that bind to specific parts of chromosomes

what is a monophyletic group?

included only the descendants from an ancestral species in which a unique feature first evolved

what are the names for evolutionary tree diagrams?


what is phylogeny?

the scientific study of evolutionary relationships

fluid mosaic model

every cell membrane has a mixed composition of phospolipids

is the cell membrane fluid, solid, or gaseous?


what is a eukaryon?

highly organized nucleus bounded by a nuclear membrane, characteristic of higher organisms

what is the endocytic pathway?

cells absorb molecules by engulfing them


Highly reactive and prone to electron transfers


makes carbonyl reactive, when combined with amino and fatty acids


the part of earth where life exists

fundamental niche

The full potential range of the physical, chemical, and biological factors a species can use if there is no competition from other species.

realized niche

the range of resources and conditions a species actually uses or can tolerate at optimal efficiency; smaller than fundamental niche

aerobic respiration

Cellular respiration that uses oxygen, sequentially releasing energy and storing it in ATP

anaerobic respiration

Respiration that does not require oxygen

peppered moths in polluted forests are an example of this

directional selection

the individual at both ends of a population are selected against

Stabilizing selection


An organism that makes its own food


organism that makes organic carbon molecules from carbon dioxide using energy from chemical reactions


organism that obtains energy from the foods it consumes; also called a consumer


Process by which organisms maintain a relatively stable internal environment

isolating mechanism

Any factor that acts to reduce or block the flow of genes between two populations


the aggregate of small plant and animal organisms that float or drift in great numbers in fresh or salt water

evolution occurs in this unit of life



evolution on the smallest scale—a generation-to-generation change in the frequencies of alleles within a population


Evolutionary change on a grand scale, encompassing the origin of new taxonomic groups, evolutionary trends, adaptive radiation, and mass extinction.

disruptive selection

natural selection that favors individuals with either extreme of a trait

shorterm adaptation

adaptation that lasts only as long as the individual organisms does (plants in windy places)

allopatric speciation

physical barriers stop gene flow among populations or subpopulations of a species. Interbreeding will no longer be possible in the offspring.


a lineage splits when one or more of its population become reproductively isolated and diverse genetically

new species definition

a species is defined by its physical, structural, and functional traits that sets them apart from other species

biological species concept

a species is one or more group of individual that interbreed, produce fertile offspring, and are reproductively isolated from other such groups


The process by which a new species evolves from a prior species, the most basic process in macroevolution.

formula used to find the frequency of genotypes in a population in which there are two alleles

hardy-weing formula

mitochondrial DNA

A small amount of DNA that is located in the mitochondria of cells. Mitochondrial DNA is inherited only through the mother.


breeding technique that involves crossing dissimilar individuals to bring together the traits of both organisms

nucleic acid hybridization

the process of base pairing between a gene and a complementary sequence on another nucleic acid molecule

molecular clock

calibrated by the determination of the number of differences in DNA base sequences or Amino Acid sequences between species being plotted against a series of branch points

physiological traits

includes metabolic activities that help the body function in the environment

In what type of species is gene swapping rampant?

prokaryotic species

homeotic gene

guide the formation of tissues and organs into orderly patterns

what elements could have played a role in the evolution of primates?

alu elements

morphological convergence

dissimilar body parts evolved in similar ways but were in evolutionary distant lineages

analogous structures

serve the same function, but are not from the same "stem" body part

morphological divergence

change from the body form of a common ancestor

specific spot of a gene on a chromosome

gene locus

piece of dna on a chromosome


what does mitosis begin with? end with?

diploid cells, diploid cells

what does meiosis begin with? end with?

diploid cells, haploid cells

what are homologous chromosomes

two chromosomes that are similar in height, shape, and genetic material

what do all cells start out with?

plasma membrane, a region of DNA, and a cytoplasm

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