(Vocab) Chapter 25: The History of Life On Earth

Macroevolution

the broad pattern of evolution above the species level

protocells

droplets with membranes that maintained an internal chemistry different from the environment

hydrothermal vents

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 hydrothermal vent community are chemoautotrophic prokaryotes.

alkaline vents

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.

montmorillonite

a mineral clay common on early Earth, increases the rate of vesicle formation

ribozymes

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

strata

The fossil record is based on the accumulation of fossils in sedimentary rock layers, called

Where are fossils mostly found?

sedimentary rock

Mineralized Organic Matter

Some fossils form as minerals seep into and replace organic matter

Amber

Entire organisms can be found preserved in hardened resin from a tree

Radiometric dating

used to determine the age of fossils based on the decay of radioactive isotopes

half-life

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

tetrapods

having four limbs

Stromatolites

layered rocks that form when prokaryotes bind thin films of sediment together

endosymbiosis

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

endosymbiont

a cell that lives within a host cell

Serial endosymbiosis

the hypothesis that mitochondria evolved before plastids through a sequence of endosymbiotic events

Cambrian explosion

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

Plate tectonics

Earth's crust is composed of plates floating on the underlying mantle

continental drift

Movements in the mantle cause the plates to gradually shift in a process

Mass extinctions

occur when large numbers of species rapidly become extinct worldwide

Adaptive radiation

a rapid period of evolutionary change where many new species arise and adapt to different ecological niches

Heterochrony

an evolutionary change in the rate or timing of developmental events

paedomorphosis

development of reproductive organs accelerates relative to other organs

Homeotic genes

master regulatory genes that determine where an organism's features will develop

Hox genes

a class of homeotic genes, provide positional information in animal embryos

Ubx gene

a homeotic gene in Drosophila that controls segment identity and regulates the number of wings and legs adult flies have

species selection

A theory maintaining that species living the longest and generating the greatest number of species determine the direction of major evolutionary trends.