Phylogenies and the History of Life

Flashcards for reviewing key concepts from biological science focusing on phylogenies and the history of life.

What is the fossil record?

The total collection of fossils that have been found, providing direct evidence of past organisms, their locations, and time periods.

What is a fossil?

The physical evidence from an organism that lived in the past.

What types of fossils do biologists study?

Intact, compression, cast, permineralized, and trace fossils.

What is an intact fossil?

Forms when decomposition does not occur and the organic remains are preserved intact.

What is a cast fossil?

Forms when a buried organism decomposes, leaving an empty cavity filled with dissolved minerals that hardens into a cast.

What is a trace fossil?

Preserves indirect evidence of an organism, such as footprints or feeding marks.

What conditions are ideal for fossilization?

Rapid burial and slow decomposition.

What is habitat bias in fossil studies?

The tendency for organisms in actively depositing sediment habitats, like beaches or swamps, to fossilize more readily.

What is temporal bias in fossils?

The phenomenon where recent fossils are more common than ancient fossils.

What is a mass extinction?

The rapid extinction of a large number of diverse species worldwide, often resulting in the loss of 60% or more of species.

What is the end-Permian extinction?

The largest mass extinction event that caused the disappearance of 90% of all species.

What triggered the Cambrian explosion?

A combination of higher oxygen levels, rise of algae, evolution of predation, and new ecological niches.

What is an adaptive radiation?

The rapid production of many descendant species from a single lineage, leading to a range of adaptive forms.

How do morphological innovations affect diversification?

Key traits can trigger significant diversification events, such as the evolution of flowers in angiosperms.

What is ecological opportunity?

The availability of new resources that drives adaptive radiations, such as the diversification of Hawaiian silverswords.

What is the Sixth Mass Extinction?

The current extinction event caused by human activities including habitat loss, pollution, and climate change.

What does the fossil record indicate about Earth's history?

It shows a timeline of the evolution of life and major events such as mass extinctions and adaptive radiations.