Biology Test #3

Evolution

Evolution

a process of biological change which species accumulate from their ancestors as they adapt over time

Variation

Increase in ability to survive

Adaption

trait favorable to environment

Homologous Structure

Similar ancestor structure

Different functions

(example) The limbs of humans, cats, whales, and bats

Analogous Structures

Different ancestor traits

Similar functions

(example) Wings in flying animals like bats, birds, insects, to fins in animals like penguins and fish

Vestigal Structures

Evidence of evolution

Structures that once served a purpose

(example) Gills and Tail

Did we once have a tail?

At one time we did have a tail, but after a couple weeks they shift away

Genetic Mutation

decrease viability of population usually detrimental to organisms

Why would it be beneficial to mutate if you were a single cell organism, and why would it be bad if you were a multiple cell?

Single cells regenerate and reproduce faster than multi cells

Genetic Drift

Gene fluctuations, loss of variation

This random event happens in a split second not over time

traits —> inheritable features = genotype

phenotypes = physical features that are not genetically based

(example) A population of rabbits with brown fur and white fur, because the brown fur is dominate only the brown population might remain and the white fur would be eliminated.

We are causing changes fast that are affecting living organisms

Genetic drift

founder effect: a few individuals from a population start a new population with a different alleles frequency than the original population —> new species

only occurs within a species

What is the result of isolation?

Increase mutation rate = mortality

decrease viability decrease viability

Intersexual selection

female chooses

(example) female peacocks choose to mate with the male with the brightest plumage

-color

-movement

-physicality

Intrasexual selection

male fights for dominance

(example) Male deer will use their antlers in contests of strength with stronger males securing more mates

Reproductive Isolation

Prezyotic barriers —> Zygote = egg + sperm

Geographic Isolation

isolated based on their location and environment

Temporal Isolation

Different mating seasons

Breeding based on season

Behavioral Isolation

certain species respond to certain movements

(example) Male fireflies use specific light patterns to attract females.

Mechanical Isolation

A does not fit B

(example) Flowering plants that do not have the correct shape for a pollinator will not receive a pollen transfer, and will therefore not be fertilized

Gametic Isolation

Sperm and an egg

Compatibility is major in Gametic Isolation

(example) Sea urchins synchronously broadcast gametes into the ocean

Post-zygotic Barriers

Reduced Hybrid Viability

Offspring that are produced ave a decrease of ability to survive

Reduced Hybrid Fertility

offspring produced cannot make children

Hybrid Breakdown

Generational decrease in survivability

Speciation (Ancestral population)

Allopatric, Parapatric, and Sympatric

Allopatric

A physical barrier divides the ancestral population. Overtime, each isolated population diverges due t natural selection or drift

Parapatric

There is some kind of habit gradient that results in locally adapted individuals

Sympatric

The extremes in the population are selected fore and there is assertive mating

Predator vs Prey

“+ -” interaction

Carnivory

“meat eaters”

Herbivory

Plant eaters

Perasitoidism

Kills host

Parasitism

Does not kill host

Predator types

Ambush—> Crocodile “Sit/wait”

Stalk—> Bird

Pursuit —> Lion

Prey

—> hiding places

increase of predators = decrease hiding

decrease of population predators = increase hiding

Search images

—> images predator/ prey

Mimicry

Senelpanity

Many offspring small

increase predator rate

(example) rodents, bugs, octopus

Interpanity

few offspring large competition

(example) Human