Bio2040 Exam 2

Three main prokaryotic cell shapes

-spheres (cocci) -rods (bacilli) -spirals

Transformation

DNA released into the environment by cell breakdown can be taken up by other cells

Hybridization

interbreeding between two different varieties or species

disruptive

In general, sympatric speciation requires the action of _____ selection acting against hybrids.

disruptive selection

In order for sympatric speciation to occur, there must be strong __________.

pre-zygotic isolation

Male birds of different species sing species-specific songs to attract mates. Females only mate with males that sing their species-specific song. This is an example of:

adaptive radiation

rapid evolutionary diversification in which natural selection accelerated the rates of speciation and adaptation

Mutations that improve the survival and reproduction of organisms, and thus contribute to the evolution of species, arise rapidly in prokaryotes due to their

rapid rate of cell division

biological species concept

species are groups of interbreeding populations that are reproductively isolated from other such groups

co-speciation

when two groups of organisms speciate in response to each at the same time

Bacterial cells are small. What does this allow them to do in terms of obtaining nutrients?

The small size allows them to obtain nutrients by diffusion

Is morphospecies concept not useful in certain situations?

Yes; in some cases, members of the same species can look different from one another

How can populations become allopatric?

by dispersal and vicariance

Which molecule is found in bacterial cell walls but is not found in archaeal cell walls?

peptidoglycan not present

habitat isolation

populations live in different habitats and do not meet

peptidoglycan

A complex polymer of sugars and amino acids that makes up the cell wall.

What does horizontal gene transfer allow bacteria to do?

Allows bacteria cells to gain beneficial genes from organisms distributed throughout the bacterial domain and beyond

gametic isolation

Incompatibility between the gametes of two different species.

Photoautotrophs

Prokaryotes that are photosynthetic and that obtain carbon from CO 2 , HCO 3 - , or related compounds are known as:

ecological species concept

The concept that there is a one-to one correspondence between a species and its niche

Relationship between the surface area and the volume of a cell

allows the interior parts of the cell to be close to their surrounding environment

reduced hybrid viability

genes of the different parent species may interact and impair the hybrid's development or survival in its environment

Transduction

horizontal gene transfer by means of viruses

The outer membrane of Gram-negative bacteria contains

lipopolysaccharides

Example of vicariance-dervied speciation

-Formation of Isthmus of Panama between Central and South America -Population of marine organisms that could previously swim through marine corridors to reach each other were now blocked from each other due to land barrier

Why was bacterial taxonomy a difficult, time-consuming process?

-Microbiologists grew bacteria in beakers or on petri dishes -carefully separating and enriching individual populations until only one type of bacterium was present

Example of dispersal-derived speciation

-New Guinea Kingfishers -Currently, 8 subspecies of bird can be seen - 3 large populations on mainland New Guinea, separated by mountains, and 5 small populations on nearby islands

Major characteristics of prokaryotes

-Shapes: sphere (cocci), rods (bacilli), and spirals -inhabit greater enviro extremes -single cell -no membrane bound nucleus

What are some extreme environments inhabited by archaea?

-acidic mine water at pH 1 -water salty enough to precipitate NaCl -deep-sea hydrothermal vents where temperatures exceed 100 degrees Celsius

Examples of prezygotic barriers

-habitat isolation -temporal isolation -behavioral isolation -mechanical isolation -gametic isolation

What is the ecological niche of a species?

-habitat requirements -nutritional and water needs

What did Carl Woese and George Fox use to justify placing Bacteria and Archaea in two separate domains?

-membranes made from lipids (ether-linked) -diversity of molecules in cell walls (no peptidoglycan, cellulose, or chitin) -linear DNA

Examples of postzygotic barriers

-reduced hybrid viability -reduced hybrid fertility -hybrid breakdown

What are. the shortcomings of BSC?

-test if they are capable of producing fertile offspring (might not be able to test due to time and resource limits) -if test is attempted, members of species might not reproduce due to unnatural environment -if the do mate, might not have time to determine if offspring are fertile -does not apply to asexual or extinct organisms

Photoheterotrophs

An organism that acquires energy from the sun and uses glucose as a carbon source would be classified as a:

reduced hybrid fertility

Even if hybrids are vigorous, they may be sterile

How do two populations become reproductively isolated from each other?

If two populations are separated from each other, over time random mutations will appear in each population and the two populations will genetically diverge

mechanical isolation

Morphological differences prevent fertilization

hybrid breakdown

Some first-generation hybrids are fertile, but when they mate with another species or with either parent species, offspring of the next generation are feeble or sterile

Conjugation

The direct cell-to-cell transfer of DNA, usually in the form of a plasmid

phylogenetic species concept

The idea that members of a species all share a common ancestry and a common fate

morphospecies concept

The idea that members of the same species usually look like each other more than like other species.

behavioral isolation

individuals that only mate w/ other individuals based on specific courtship rituals, songs, and other behaviors

allopatric populations

populations that are geographically separated from each other

sympatric populations

populations that are in the same place, not geographically separated

When taxonomists recognize subspecies, they are identifying:

populations with restricted enough gene flow to develop some population-specific traits, but that can still interbreed with members of other such populations

temporal isolation

two populations reproduce at different times

vicariance

where a geographic barrier arises within a population

Dispersal (Peripatric Speciation)

where individuals colonize a distant place Ex. an island