Biology exam review

5 conditions for a population to be in Hardy Weinberg Equilibrium:

● No Mutations

● No immigration/emigration

● No natural selection

● Random mating (no purposeful selection of partners)

● A large population

Genetic drift-

the change in frequency of an existing gene variant in the population due to

random chance.

Example: Forest fire (the remaining organisms are not necessarily the original allele frequency)

Gene flow-

passing of genes from a different population or species.

Example: Migration (one species migrates to a new ecosystem)

Speciation-

the evolutionary process by which a single ancestral species diverges into two or

more distinct species.

Example: Galapagos Finches (species of birds that were spread across the galapagos islands and adapted to their environment)

Homologous structures-

Homologous structures are organs or bones of animals that show

similar structure.

Vestigial structures-

appear to have no purpose.

i. Example: A human Coccyx(tailbone)

DNA sequencing / amino acid sequencing-

similarities

between genes and proteins between organisms

Overproduction-

a species producing more offspring than can survive and

reproduce

Genetic Variation-

the differences in the DNA sequences of genes among

individuals and populations

Competition-

an interaction between organisms or species in which both

require a resource that is in limited supply

Survival of the Fittest-

an interaction between organisms or species in which

both require a resource that is in limited supply

Descent with Modification-

the concept that living organisms have evolved from common

ancestors over time, with each subsequent generation inheriting traits from their predecessors,

while also exhibiting modifications or changes in those traits

Stabilizing Selection-

The intermediate phenotype shows the best fitness.

Disruptive Selection-

The intermediate phenotype is the least fit.

Directional Selection-

species change slowly and continuously over vast periods of time.

Punctuated equilibrium-

species remain relatively stable for long stretches, with rapid periods of change

occurring periodically, often during speciation events.

the steps of lytic viral infection.

Step 1: Attachment-

Step 2: Entry-

Step 3: RNA Synthesis-

Step 4: Assembly-

Step 5: Release-

Step 1: Attachment-

The virus attaches to the

host cell through specific receptors on the cell

surface.

Step 2: Entry-

The virus injects its genetic

material (DNA or RNA) into the host cell.

Step 3: RNA Synthesis-

The viral genetic material

is replicated using the host cell's machinery. The

host cell's DNA is degraded, and the cell is

directed to produce viral proteins.

Step 4: Assembly-

New viral particles are assembled from the replicated DNA and proteins.

Step 5: Release-

The host cell is lysed (burst open), and the newly assembled viruses are

released to infect other cells.

Positive Feedback Loop-

amplifies a change, moving a system further away from its original state, rather than

returning it to a stable equilibrium

Negative Feedback Loop-

a regulatory mechanism where a stimulus triggers a response that opposes

the initial stimulus, bringing a system back to a stable state, or homeostasis

Homeostasis-

the process by which living organisms maintain a stable internal environment despite external changes

Phototropism-

the directional growth or movement of a plant or part of a plant in response to

light

Thigmotropism-

a plant's directional growth response to physical contact or touch with an object

Gravitropism-

a plant's directional growth or change in the direction of its growth in response

to gravity

Detrivore-

Organism that breaks down dead organic material for nutrients

Primary succession-

the initial colonization of a previously uninhabited environment, like newly

exposed rock after a volcanic eruption or glacial retreat, by organisms

Pioneer species-

the first organisms to colonize a previously barren or disturbed environment, initiating

ecological succession

Secondary succession-

the process of ecological recovery that occurs in an area where a pre-existing

community has been disturbed, but not completely destroyed

Climax community-

the stable, final stage of ecological succession in a specific environment

Mutualism-

is a relationship where both organisms benefit.

Example: Water buffalo and Oxpeckers (Oxpecker eats the ticks off the water buffalo and the water buffalo are free from disease)

Parasitism-

one organism is harmed and the other benefits.

Example: tick and dog (tick feeds off the blood of a dog, the dog is harmed)

Commensalism-

one organism benefits and the other is unaffected

Example: Barnacle and Whale (the barnacles benefit by eating the microbes and the

whale is not harmed or helped)