Bio221 - Ch 25

Front 1

Macroevolution

Back 1

Evolutionary change above the species level. Examples of _____ary change include the origin of a new group of organisms through a series of speciation events and the impact of mass extinctions on the diversity of life and its subsequent recovery.

Front 2

Protocell

Back 2

An abiotic precursor of a living cell that had a membrane-like structure and that maintained an internal chemistry different from that of its surroundings.

Front 3

Hydrothermal vent

Back 3

An area on the seafloor where heated water and minerals from Earth’s interior gush into the seawater, producing a dark, hot, oxygen-deficient environment. The producers in a _____ community are chemoautotrophic prokaryotes.

Front 4

Alkaline vents

Back 4

A deep-sea hydrothermal vent that releases water that is warm (40–90°C) rather than hot and that has a high pH (is basic). These vents consist of tiny pores lined with iron and other catalytic minerals that some scientists hypothesize might have been the location of the earliest abiotic synthesis of organic compounds.

Front 5

Rybozyme

Back 5

An RNA molecule that functions as an enzyme, such as an intron that catalyzes its own removal during RNA splicing.

Front 6

Radiometric dating

Back 6

A method for determining the absolute age of rocks and fossils, based on the half-life of radioactive isotopes.

Front 7

Half-life

Back 7

The amount of time it takes for 50% of a sample of a radioactive isotope to decay.

Front 8

Geologic record

Back 8

A standard time scale dividing Earth’s history into time periods, grouped into four eons—Hadean, Archaean, Proterozoic, and Phanerozoic—and further subdivided into eras, periods, and epochs.

Front 9

Stromatolite

Back 9

Layered rock that results from the activities of prokaryotes that bind thin films of sediment together.

Front 10

Endosymbiosis

Back 10

A relationship between two species in which one organism lives inside the cell or cells of another organism.

Front 11

Serial endosymbiosis

Back 11

A hypothesis for the origin of eukaryotes consisting of a sequence of endosymbiotic events in which mitochondria, chloroplasts, and perhaps other cellular structures were derived from small prokaryotes that had been engulfed by larger cells.

Front 12

Cambrian explosion

Back 12

A relatively brief time in geologic history when many present-day phyla of animals first appeared in fossil record. This burst of evolutionary change occurred about 535-525 millions years ago and saw the emergence of the first large, hard-bodied animals.

Front 13

Plate tectonics

Back 13

The theory that the continents are part of great plates of Earth’s crust that float on the hot, underlying portion of the mantle. Movements in the mantle cause the continents to move slowly over time.

Front 14

Pangaea

Back 14

The supercontinent that formed near the end of the Paleozoic era, when plate movements brought all the landmasses of Earth together.

Front 15

Mass extinction

Back 15

The elimination of a large number of species throughout Earth, the result of global environmental changes.

Front 16

Adaptive radiation

Back 16

Period of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological roles in their communities.

Front 17

Heterochrony

Back 17

Evolutionary change in the timing or rate of an organism’s development.

Front 18

Paedomorphosis

Back 18

The retention in an adult organism of the juvenile features of its evolutionary ancestors.

Front 19

Homeotic gene

Back 19

Any of the master regulatory genes that control placement and spatial organization of body parts in animals, plants, and fungi by controlling the developmental fate of groups of cells.