ch 14: The history of Life

Biodiversity

The variety of all the world’s living things

domains

a classification system for biodiversity (bacteria, Archaea, Eukarya), describe the most basic and ancient divisions among living organisms.

domains for prokaryotes

bacteria and archaea

Cambrian period

During this time, most major animal groups appeared in the fossil record, including the earliest vertebrates, and many organisms developed hard-shelled exoskeletons for the first time. Life was exclusively aquatic, and environmental changes like increased oxygen levels and new shallow marine habitats are thought to have fueled this evolutionary burst.

lineage

line of descent from a common ancestor

Theropods

fast-moving, two-legged, hollow-boned, group of dinosaurs

evolutionary tree

a model of evolutionary relationships among groups of organisms based on similarities and differences in their DNA, physical features, biochemical characteristics, or a combo of these

clade

a branch on the evolutionary tree

node

marks the moment in time when an ancestral group split, or diverged, into 2 separate lineages

most recent common ancestor

the most immediate ancestor that both lineages share

shared derived traits

unique features common to all members of a group that originated in the group’s most recent common ancestor

protista

diverse, single-celled group that includes amoebas and algae

plantae

all plants

fungi

includes mushrooms, molds, and yeasts

animalia

all animals, including dinosaurs, birds, and humans

Linnean hierarchy

a system of biological classification devised in the 18th century by the Swedish naturalist Carolus Linnaeus

order of categories

kingdom, phylum, class, order, family, genus, species

scientific name

genus, species; capitalized, not capitalized

mass extinctions

periods of time during which great numbers of species go extinct

causes of mass extinctions

climate change, massive volcanic eruptions, changes in the composition of marine and atmospheric gases, sea level changes

adaptive radiation

When a group of organisms expands to take on new ecological roles and to form new species and higher taxonomic groups