evolution & microbiology

natural selection

when a heritable trait becomes common in a population due to individuals having the trait surviving

evolution

genetic changes over time in the population

variation

differences in the traits or phenotypes, can be physical, behavioral, etc

fitness

ability to survive and reproduce

frequency

helps individuals survive, will increase over time

selective breeding/artificial selection

humans breed different organisms based on traits they feel desirable

fossil

a remnant or trace of an organism from the past

relative dating

use a fossils placement in rock layers to determine age

absolute dating

uses the amount of radioactive isotopes to determine actual age

homologous structures

similar in structure yet different in function

vestigal structures

do not have a function, may have had one in the past

analogous structures

different in structure, same in function

gene pool

collection of all alleles present in a population

genetic drift

random changes in small gene pools due to chance events

bottleneck effect

natural events result in death of a large percentage

founder effect

small group of individuals break off and colonize a new area

gene flow

movement of alleles into and out of a gene pool

mutations

changes in the gene of an organism brings new variations

nonrandom mating

individuals will mate more frequently with close individuals than more distant ones

polygenic traits

traits controlled by many genes (eye, height)

directional selection

extreme phenotype is favored

stabilizing selection

intermediate phenotypes of a trait are favored

disruptive selection

extreme/both phenotypes are favored

speciation

formation of a new species

species

group of organisms that breed and produce fertile offspring

reproductive isolation

when populations are divided, prevents members from reproducing

prezygotic barriers

prevent the formation of a zygote

postzygotic barriers

keep organisms from developing into healthy adults

allopatric speciation

when a geographic barrier separates members of a population

adaptive radiation

when a single species gives rise to a variety, each adapted to a specific enviornment

sympatric speciation

occurs without a geographic barrier

mechanical isolation

sexual organs don’t fit

temporal isolation

females are fertile at a certain time but males are not

behavioral isolation

mating rituals signal it’s time to reproduce

habitat isolation

preferred locations are incompatible between species

gametic isolation

only sperm of the same species works with the egg, if they’re not compatible it won’t work (WATER)

zygote mortality

zygote does not survive to birth, germination, or will never make it to the reproductive ages

hybrid sterility

offspring is sterile

F2 fitness

first gen is healthy, second gen is sterile or unhealthy

gradualism

slowly and constantly over time

punctuated equilibrium

appear suddenly, and then unchanged

prokaryotes are also known as

bacteria

prokaryote traits

no neucleus or membrane organelles, peptidoglycan in cell wall, loop structure

eukaryotes example

plants or animals

eukaryote traits

neucleus, membrane organelles, no peptidoglycan, chromosomes

spirilli

spiral shape

cocci

circle shape

bacilli

rod shape

tetrad

group of 4

strepto

chain

diplo

pairs

staphylo

clusters

gram staining purpose

diagnoses harmful bacteria based on the chemical properties of their cell walls

gram positive

purple, thick, no lipids

gram negative

red or pink, thin, lipids

antibiotics

in the body, targets bacteria

antiseptics

on the body, viruses and bacteria

disinfectants

on surfaces, viruses and bacteria

cell wall stops bacteria

prevents from building

ribosomes stop bacteria

can’t make proteins

RNA and DNA stop bacteria

prevents from making proteins, dna replication, transcription

zone of inhibition

measure of the substances effectiveness

virus characteristics

small, lacking enzymes and organelles

can viruses reproduce outside of a living cell

no, only in the host cell

capsid

protein coat

nucleic acid in viruses

DNA or RNA

envelope

layer surrounding the capsid consisting of phospholipids

how does a virus enter host cell

it attaches to the receptors on the membrane

bacteriophages

viruses that infect bacteria

lytic cycle

virus attaches to surface and injects DNA, makes more copies, assembles into new, bursts and kills the host

lysogenic cycle

virus attaches to surface and injects DNA, virus DNA incorporates with host DNA and is replicated, virus parts assemble and make more copies, burst and kills host