Taxonomy

What is taxonomy?

The science of classifying organisms.

What are the major taxonomic groups of the Linnean classification system?

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

What is binomial nomenclature?

The two-word convention of naming species, consisting of the Genus and specific epithet.

How is the Genus name formatted in binomial nomenclature?

The Genus name is capitalized and italicized.

How is the specific epithet formatted in binomial nomenclature?

The specific epithet is written in lowercase and italicized.

What are the three recognized domains in taxonomy?

Bacteria, Archaea, and Eukarya.

Which domains are thought to be more closely related?

Archaea and Eukarya.

What are the characteristics of organisms in Domain Bacteria?

Prokaryotic, unicellular, reproduce via binary fission, and have cell walls composed of peptidoglycan.

What distinguishes Domain Archaea from Domain Bacteria?

Archaea have distinct cell membrane chemistry and do not have peptidoglycan in their cell walls.

What is a key feature of Domain Eukarya?

Eukaryotic cells contain a membrane-bound nucleus and organelles.

What types of organisms are included in Domain Eukarya?

Protists, plants, fungi, and animals.

What is the estimated age of Earth?

Approximately 4.6 billion years ago.

When did prokaryotes first appear in the fossil record?

Approximately 3.5 to 3.8 billion years ago.

When did eukaryotes first appear in the fossil record?

Approximately 1.6 to 2 billion years ago.

What is adaptive radiation?

The rapid speciation of an ancestral lineage into many descendants adapted to diverse niches.

What can trigger adaptive radiation?

New ecological opportunities, lack of competition, or key innovations.

Give an example of adaptive radiation.

Hawaiian honeycreepers evolved from a common ancestor into many species adapted to different food sources.

What is the Cambrian explosion?

A period of rapid diversification in animal lineages around 530 million years ago.

What distinguishes mass extinctions from background extinctions?

Mass extinctions wipe out the majority of species in a short time, while background extinctions occur at varying rates.

What are hypothesized causes of mass extinctions?

Abrupt environmental changes, such as volcanic activity, climate change, or asteroid impacts.

What evidence suggests a sixth mass extinction may be occurring?

Evidence indicates that human activity is primarily causing this potential extinction event.

What is the role of niches in adaptive radiation?

Niches refer to a species' role in the environment, including space occupied and resources used.

What is the significance of the phylogenetic relationship between Archaea and Eukarya?

They are thought to share a more recent common ancestor than either does with Bacteria.

What is the difference between unicellular and multicellular organisms in Domain Eukarya?

Unicellular organisms consist of a single cell, while multicellular organisms are composed of multiple cells.

What is the primary method of reproduction for prokaryotes?

Binary fission.

What is a characteristic of Kingdom Animalia?

Multicellular heterotrophs that feed by ingestion.

What is a characteristic of Kingdom Plantae?

Multicellular photosynthetic species (autotrophs).

What defines the protists in Domain Eukarya?

An extremely diverse group that can be uni- or multicellular and autotrophic or heterotrophic.

What is the significance of the estimated appearance of multicellular taxa?

Most familiar multicellular taxa evolved within the past 550 million years.