evolution and domestication

What is Evolution?

The process by which living organisms change over generations due to genetic variation and environmental pressures.

What Four Ways do Evolution Occur? (4)

it occurs through mutation

Mutation

random changes in DNA that may create new traits. only heritable if in germ cells.

Natural Selection

where individuals with traits best suited to their environment survive and reproduce.

Migration (gene flow)

new genes enter or leave a population

Genetic drift

random changes in gene frequencies

What is natural selection and how does it drive evolution?

natural selection is a key mechanism of evolution. individuals with advantageous traits (e.g better camouflage

Name the four mechanisms of evolution

Natural selection

What is one example of natural selection in action in insects?

peppered moths- during the Industrial Revolution

What is one example of natural selection in action with birds?

Darwins finches shows the evolution in beak shapes based on the type of available food on each Galápagos Islands

What is genetic variation?

genetic variation refers to the differences in DNA between individuals. it provides the raw material for evolution.

Why is genetic variation important?

Without variation

what is domestication?

the process of genetically adapting a wild animal species to live alongside humans

what is the difference between domestication and taming?

taming is behavioural and involves training an individual wild animals to accept human handling

what are the three areas of permanent genetic change in domestication?

physiology

what behavioural traits are common in domesticated animals (5)?

increased sociability and tolerance to humans

five morphological changes occur in domesticated animals?

smaller teeth and gas

four physiological changes seen in domesticated species?

reduced adrenal response to stress (lowered flight distance)

what six things make an animal a good candidate for domestication

1. herding behaviour or clear social hierarchy

2. fast growth and early maturity

3. ability to breed in captivity

4. calm temperament

5. simple diet (herbivores preferred)

6. hardy and adaptable

give four examples of good animals to domesticate and two poor examples

good: sheep

how did domestication begin historically?

the first domesticated animals were likely wolves that scavenged near human camps. humans benefitted from their protection and hunting help

what are the five key stages of domestication?

1. taming

2. captive breeding

3. selective breeding

4. genetic isolation

5. true domestication

what is taming

when an individual animal becomes used to humans (e.g a wild bird that eats from your hands)

what is captive breeding

the controlled breeding of animals in a human managed environment

what is selective breeding

aka artificial selection

what is genetic isolation

where a group of animals or plants become separated from others of the same species

what is true domestication

long term

how has domestication altered the use and appearance of chickens

from 2lb wild ancestors to 17lb meat birds

how has domestication altered the use and appearance of cattle

bred for docility

how has domestication altered the use and appearance of dogs

thousands of breeds with specialised roles (herding

what is the story of Darwins finches

Darwins beagle voyage in the 1830s let to him mistaking different finches for blackbirds and wrens

what is adaptive variation?

when one species evolves into many different species

explain the term survival of the fittest

this does not mean just the strongest

what is somatic mutation

a change in the DNA that happens in non-reproductive cells

what is an example of genetic variation?

Playing possum (opossums feigning death as a defence mechanism)

what are three characteristics of somatic mutations?

1. can happen at any point in your life

2. are not inherited by offspring

3. might cause issues like cancer

but they only affect the individual

give an example of somatic mutation

if a mutation happens in your skin cells from sun damage

what is germline mutation?

a change in DNA that occurs in reproductive cells - sperm or egg cells.

what are three characteristics of germline mutation?

1. can be inherited by offspring

2. are present in every cell of the baby's body if passed on

3. contribute to evolution

because they affect the gene pool

what is an example of gremlin mutation?

if a parent has a gremlin mutation in the gene for PRA (progressive retinal atrophy)

what is the difference between somatic and gremlin mutation?

somatic is not passed to offspring

Define biogeography

biogeography is the study of how and why different species are distributed around the world (the science of why do these animals live here and how did they get here?)