Speciation and Extinction Flashcards

Flashcards about Speciation and Extinction based on lecture notes.

What is Macroevolution?

Large changes in organisms over long periods of time resulting in new species and higher taxa.

What are Species concepts?

Standardized approaches used to define what a species is.

What is Taxonomy?

The science of classifying and grouping organisms based on similarities.

According to the Biological Species Concept, what defines a species?

Members of populations that interbreed to produce viable and fertile offspring.

What do nodes on phylogenetic trees indicate?

Phylogenetic trees are hypotheses of how these organisms evolved.

What is speciation?

Describes when an ancestral population diverges into 2+ different species.

What is the most direct way to achieve reproductive isolation leading to speciation?

Physical/geographic barriers.

What is the Ring species effect?

Geographical separation and reproductive isolation through incremental genetic changes.

What is prezygotic isolation?

Mechanisms that can prevent zygote formation (limit sex from occurring).

What is postzygotic isolation?

Mechanisms that limit the viability of offspring.

What are examples of prezygotic isolation?

Habitat, Temporal, Behavioral, Mechanical, and Gametic isolation.

What are examples of postzygotic isolation?

Hybrid inviability, Hybrid infertility/sterility, and Hybrid breakdown.

What is Allopatric speciation?

No contact between populations.

What is Sympatric Speciation?

Continuous contact between populations.

How does allopatric speciation occur rapidly on island chains?

The founder effect and genetic drift can cause rapid evolutionary change in founder populations.

What is sympatric speciation?

Speciation without obvious geographic barriers.

What is Polyploidy?

3+ full copies of all chromosomes.

What is adaptive radiation?

The rapid emergence of many species from a single founder species in a new environment.

What is Gradualism?

Selection and variation happens gradually; change is slow, constant, consistent.

What is Punctuated Equilibrium?

Selection and variation may happen in bursts followed by long periods with little change.

What is Extinction?

When all members of a species die out.

What is the Impact theory?

Meteorites occasionally crashed to earth leading to extinctions.

What is Systematics?

The study of organismal classification which incorporates taxonomy and phylogenetics.

What is Taxonomy?

The science of naming, describing, and classifying species into nested groups (taxa).

What is Phylogenetics?

The study of evolutionary history and relationships between organisms

What is Binomial nomenclature?

Referring to unique groups of highly related organisms by both genus and species names.

What is cladistics?

A phylogenetics approach that defines evolution based on shared biological features or “characters”.

What is a clade?

Group of organisms that include the common ancestor and all descendants.