9A
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What is environmental variation
the ability of an organism to alter its Dna depending upon environmental conditions.
Examples of environmental variation
Hair length - what length you choose to have your hair. Scars - caused by accidents personal to you. Muscle strength
How is environmental variation caused
climate, diet, accidents
Examples of discontinuous variation
Blood group
Continous variation
it ranges from the shortest to the tallest and any height in between both environmental and inherited variation
Discontinous variation
Describes characteristics that can only be one of a number of limited options, usually inherited
What is inherited variation
is a result of genetic information from the parents when they get half of their DNA and inherited features from each parent
Examples of inherited variation
eye color, height,skin color
How is inherited variation caused
variation is caused by parents mating and then passing on dna from parents to offspring
Where is genetic information stored
In dna molecules
What does genetic information do?
Provides instructions or code to make proteins which provide characteristics
What is normal distribution
which most values cluster in the middle of the range and the rest taper off symmetrically towards the sides
What are chromosomes made of
A chromosome is made up of proteins and DNA organized into genes.
Number of pairs in most human cells
23
Where are genes found?
In chromosomes
What do genes do
carry the information that determines your traits inherited from your parents
What roles did watson,crick,franklin and wilkins play in the structure of dna
Franklin - photos of dna with xrays Watson - helped build double helix model Wilkins - spent years testing the double helix model Crick - recognized the shape spiral molecules on xray photos
How can changes in the ecosystem cause endagerment or exintion
Changed in physical environmental factors,competition from others and human activities
Methods of conservation of animals
banning the hunting of certain animals,setting up nature reserves and starting breeding programs
How can adaptations affect the chances if survival in a habitat
Adaptations like polar bears having white fur helps them camaflouge and for warmth and the black skin for absorbing heat
Why is preserving biodiversity important
A wide variety of species will cope better with threats than a limited number of them in large populations.
Role of gene banks
gene banks are used to store and conserve the plant genetic resources of major crop plants and their crop wild relatives.
How can natural selection lead to evolution
Organisms that are more adapted to their environment are more likely to survive and pass on the genes that aided their success
Examples of continous variation
Height,foot length,hand span