Concept 1.2: Evolution accounts for the unity and diversity of life

Flashcards from Concept 1.2 of Pearson's Campbell Biology, Twelfth Edition.

Evolution

The concept that living organisms are modified descendants of common ancestors, supported by an abundance of evidence

1.8 million

The approximate number of species that have been identified and named to date

10 to 100 million

The estimated amount of species that actually exist

Domains

The three subdivisions of organisms:

• Bacteria

• Archaea

• Eukarya

Prokaryotes

Classification that includes the domains of Bacteria and Archaea

Eukaryotes

Classification that includes the Eukarya domain

Eukarya

Domain that is broken down into four subgroups:

• Plants (photosynthesize food)

• Fungi (absorb food)

• Animals (ingest food)

• Protists (diverse group related to all of the above)

Protists

The most numerous and diverse eukaryotes that are mostly single-celled organisms, related to plants, animals, or fungi more than other protists in some cases

Dioxyribonucleic acid (DNA)

The universal genetic language common to all organisms that forms a unity despite the diversity of life

Fossils

Preserved geological records that show skeletal similarities across organisms over billions of years

Charles Darwin

Scientist who published his On the Origin of Species in 1859, showing evidence of common ancestors and the idea of “natural selection” through the competition of inherited traits in an environment

Natural selection

The evolutionary process that states that individuals with the most advantageous traits will receive higher reproductive success, thus spreading beneficial traits throughout an environment

Common ancestor

An initial species that gives rise to two or more descendant species as a result of natural selection; relationships with these ancestors are illustrated in treelike diagrams