Speciation, Prokaryotes, and Protists Review

Comprehensive flashcards covering speciation concepts, prokaryotic structures and diversity, and the classification and medical importance of protists based on Chapter 14, 17, and 18 lecture materials.

What is the difference between microevolution and macroevolution?

Microevolution refers to small evolutionary changes that accumulate in a population over a few generations, while macroevolution refers to slower, large-scale changes.

Who created the naming scheme for species in the 1700s that combines genus and species?

Carolus Linnaeus

How does the biological species concept define species?

By their potential to interbreed and produce fertile offspring.

According to DNA analysis, what is the threshold for bacteria and archaea to be considered the same species?

If their DNA is more than $97\%$ identical.

What is the distinction between prezygotic and postzygotic reproductive barriers?

Prezygotic barriers prevent the formation of an embryo, while postzygotic barriers result in hybrid individuals with reduced fitness or the prevention of fertile offspring development.

What occurs in allopatric speciation?

A physical barrier geographically separates a population into two groups that cannot interbreed.

What characterizes parapatric speciation?

Part of a population enters a new habitat bordering the parent species' range; while mating between populations can occur, most individuals mate within their own population.

How do populations diverge in sympatric speciation?

Populations diverge genetically while living together in a shared habitat, often due to different microenvironments.

Compare gradualism and punctuated equilibrium.

Gradualism suggests evolution proceeds in small, incremental changes over many generations, while punctuated equilibrium suggests long periods of little change are interrupted by bouts of rapid change.

How many mass extinctions does the fossil record show in the last $600$ million years?

Five mass extinctions.

In cladistics, what is the difference between ancestral and derived traits?

Ancestral traits are inherited from an ancestor, while derived traits are not inherited from an ancestor.

What is a clade?

A group of organisms consisting of a common ancestor and all of its descendants, also called a monophyletic group.

Why is the group "Reptiles" considered paraphyletic?

It includes a common ancestor but excludes some descendants (specifically birds).

What defines a polyphyletic group, such as "endothermic animals"?

It excludes the most recent common ancestor of its members; for endotherms, the common ancestor of birds and mammals was not endothermic.

What is a prokaryote?

A single-celled organism that lacks a nucleus and membrane-bounded organelles, including bacteria and archaea.

What are plasmids in prokaryotic cells?

Circles of DNA located apart from the chromosome.

What is the function of the glycocalyx?

A layer of proteins or polysaccharides that helps cells attach to surfaces, form biofilms, and evade the immune system.

What are sex pili used for in bacteria and archaea?

Exchanging DNA with other cells.

What is taxis?

A response that enables cells to move toward or away from external stimuli using flagella.

What are endospores?

Thick-walled structures formed by some bacteria to survive harsh conditions, such as Clostridium botulinum.

What characterizes Gram-positive bacterial cell walls?

A thick peptidoglycan (carbohydrate) layer.

List the three most common shapes for bacteria.

Coccus (spherical), bacillus (rod-shaped), and spirillum (spiral).

Differentiate between photoautotrophs and chemoautotrophs.

Photoautotrophs derive energy from the sun, while chemoautotrophs use inorganic chemicals like sulfur and iron.

What is the difference between obligate aerobes, obligate anaerobes, and facultative anaerobes?

Obligate aerobes require $O_2$ to live; obligate anaerobes are killed by $O_2$; and facultative anaerobes can live in either environment.

How does horizontal gene transfer differ from vertical gene transfer?

Vertical gene transfer (binary fission) is asexual reproduction from ancestor to offspring, while horizontal gene transfer involves receiving DNA from a cell that is not its ancestor.

Which bacterial phylum is the largest group of gram-negative bacteria and includes Vibrio cholerae?

Proteobacteria

What is the ecological significance of Cyanobacteria?

They were the first cells to release $O_2$ gas as a byproduct of photosynthesis and gave rise to chloroplasts via endosymbiosis.

Which bacterial phyla are known for causing Lyme disease and syphilis?

Spirochaetes (specifically Borrelia burgdorferi and Treponema pallidum).

What are extremophiles and which domain are they often associated with?

Organisms that live in extreme habitats (lack of oxygen, high heat, high salt, or acid), primarily associated with domain Archaea.

What is the role of nitrogen-fixing prokaryotes like Rhizobium?

They convert $N_2$ into ammonia, which most other organisms can use.

How are protists traditionally classified into three groups?

Algae (plant-like), slime molds/water molds (fungus-like), and protozoa (animal-like).

What indicates that chloroplasts in red algae, green algae, and plants developed from primary endosymbiosis?

They have two membranes.

What indicates secondary endosymbiosis in brown algae and euglena?

Their chloroplasts have three membranes.

Which protists have silica cell walls and yellowish pigments?

Diatoms

What causes red tides?

The overgrowth and toxin production of Dinoflagellates.

What is the mobile stage of cellular slime molds when resources become limited?

A "slug," which later forms a fruiting body to produce spores.

Which protozoa move using pseudopodia and include the pathogen Entamoeba?

Amoeboid protozoa

Which marine amoeboid protozoa have calcium carbonate ($CaCO_3$) shells used to date rock layers?

Foraminiferans (Forams)

What are the characteristics of Ciliates?

Mostly unicellular, they use hairlike cilia for propulsion and feeding, and possess specialized structures like food vacuoles and an anal pore.

What disease is caused by Plasmodium, and how is it transmitted?

Malaria; it is carried by mosquitoes and infects human red blood cells.