Exam 2 Review – Speciation, History of Life, and Prokaryotes

This set of flashcards covers key concepts from Chapters 22-24, focusing on speciation, the history of life on Earth, and characteristics of prokaryotes.

What are the three species concepts discussed in Chapter 22?

Morphological, biological, and lineage species concepts.

What causes reproductive isolation between species?

Genetic differences leading to mechanisms like the Dobzhansky-Muller Model.

What is allopatric speciation?

Speciation that occurs due to geographic separation.

What is sympatric speciation?

Speciation that occurs without geographic separation, often through polyploidy.

What is the difference between autopolyploidy and allopolyploidy?

Autopolyploidy involves duplication of the same species’ chromosomes, whereas allopolyploidy involves the hybridization of different species.

What are pre-zygotic isolation mechanisms?

Mechanisms that prevent fertilization and include mechanical, temporal, behavioral, habitat, and gametic isolation.

What are some examples of post-zygotic isolation mechanisms?

Low hybrid zygote vigor, low hybrid adult viability, and hybrid infertility.

What is hybridization?

The process of interbreeding between two different species.

What factors influence the rate of speciation?

Occupying specific niches and dietary specialization.

What is the geological time scale?

A timeline that represents the history of Earth and the evolution of life.

What is radiometric dating?

A method used to date materials, such as rocks and fossils, based on the decay of radioactive isotopes.

What is the significance of the Cambrian explosion?

A major event approximately 541 million years ago marked by a rapid diversification of life.

What are the four major eons of Earth's history?

Hadean, Archaeon, Proterozoic, and Phanerozoic.

What do prokaryotes include?

Bacteria and Archaea.

How do bacteria and archaea exchange genetic material?

Through lateral gene transfer.

What is the difference between Gram-positive and Gram-negative bacteria?

Gram-positive bacteria have thick peptidoglycan layers while Gram-negative bacteria have a thin layer and an outer membrane.

What is the role of biofilms in health and ecosystems?

Biofilms are communities of microorganisms that can enhance the survival and functionality of the microbiome.

What are Koch's postulates?

Criteria used to establish a causative relationship between a microbe and a disease.

What is a virus?

A small infectious agent that replicates only inside living cells.

What is a bacteriophage?

A type of virus that infects and replicates within bacteria.

What is an extremophile?

An organism that thrives in extreme environmental conditions.