chapter 22/23

What is speciation?

Speciation is the evolutionary process by which populations evolve to become distinct species.

What are the three species concepts?

The three species concepts are the Biological Species Concept, Morphological Species Concept, and Phylogenetic Species Concept.

What defines the Biological Species Concept?

The Biological Species Concept defines species based on the ability to interbreed and produce viable offspring, emphasizing reproductive isolation.

What are reproductive isolating mechanisms?

Reproductive isolating mechanisms are biological features that prevent different species from interbreeding, ensuring species remain distinct.

What are the two main categories of reproductive isolating mechanisms?

The two main categories are prezygotic mechanisms (prevent mating or fertilization) and postzygotic mechanisms (prevent viable offspring).

What is the difference between prezygotic and postzygotic mechanisms?

Prezygotic mechanisms prevent the formation of zygotes, whereas postzygotic mechanisms occur after fertilization and may involve inviability or infertility of the hybrids.

What is allopatric speciation?

Allopatric speciation occurs when populations are geographically isolated, leading to the evolution of new species.

What is sympatric speciation?

Sympatric speciation occurs without geographical isolation; species evolve differences while living in the same area.

What is polyploidy?

Polyploidy is the condition of having more than two complete sets of chromosomes, often found in plants.

How do fossils act as intermediate forms between living organisms and extinct organisms?

Fossils provide evidence of evolutionary transitions, showing features that are common to both living species and their extinct ancestors.

What is convergent evolution?

Convergent evolution is when unrelated species evolve similar traits due to similar environmental pressures.

What is divergent evolution?

Divergent evolution occurs when two related species become more different over time, usually due to different environments.

What are analogous traits?

Analogous traits are traits that serve similar functions in different species but do not share a common evolutionary origin.

What are homologous traits?

Homologous traits are characteristics that are similar due to shared ancestry, even if their functions differ.

What is adaptive radiation?

Adaptive radiation is the rapid evolution of diversely adapted species from a common ancestor to fill different ecological niches.

What are the major extinction events in Earth's history?

Significant extinction events include the Ordovician-Silurian, Late Devonian, Permian-Triassic, Triassic-Jurassic, and Cretaceous-Paleogene extinctions.

What causes extinction events?

Extinction events can be caused by factors such as climate change, habitat loss, volcanic eruptions, and asteroid impacts.

What is the 6th extinction?

The 6th extinction is the ongoing extinction event caused primarily by human activity, resulting in the loss of biodiversity.

How do scientists determine the ages of fossils?

Relative ages are determined through stratigraphy, while absolute ages are determined through radiometric dating techniques.

What is the role of plate tectonics in evolution?

Plate tectonics affects the distribution of species, leading to geographic isolation, and thus influencing evolutionary processes.