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Natural Selection - Coggle Diagram
Natural Selection
Other information
Theory of Natural selection was proposed by Charles Darwin
he defined evolution as descent with modicfication
This meant a species changes over time
Majority of offspring don't survive to sexual maturity.
Frequency of a trait in a population can be measured.
Before the theory was presented scientists didn't have a theory for evolution
Evolution can be seen from fossil evidence
if an environment changes too quickly some species wont be able to adapt fast enough
Theory that all animals came from a common ancestor
Why is natural selection important?
Causes populations to become better adapted to environment.
Allows newer generations to thrive, survive and reproduce
Evolves species to rapidly changing environments
Provides explanation for how populations evolve.
What are key features of natural selection?
Traits:
Heritable traits mean that the trait can be passed on to offspring
Acquired traits cannot be passed on to offspring
Natural selection only occurs when a genetic trait has a function or use giving an advantage in the environment.
Variation in traits occurs from genetic mutation
Selection pressures
Challenges that affect an organism’s ability to survive and reproduce in an environment.
Access to food
Access to water
Access to shelter
Predators hunting population
Number of available mates
Diseases
Human activity
Dictates the way an organism a species changes
Affects the frequency of a trait in a population.
VASRP
Varitaion
Differences in individuals in a population regarding specific traits
This process is natural
Caused by genetic mutation
Adaption
Traits granted by variation allow organism to adapt to selection pressures.
These individuals survive better then those without variation
Survival
Survival of the Fittest
Individuals better adapted survive and are able to reproduce
Reproduction
Organisms that survive are able to reproduce many times
Pass on genes and traits to offspring
Population over time
Over many generations offspring survive better and reproduce
Offspring reproduce and cycle continues
Trait becomes more common in the population
What is evolution by natural selection?
Evolution
Creating organisms with different variations of preexisting species forming new ones
Done through cumulative inherited changes in a population over many generations
Natural selection
Process in which organisms who are better adapted to survive in their population are able to survive and reproduce.
Allows them to pass on their genes to offspring making the adaption more common in the population.
Real world examples of natural selection
Peppered Moths
Early 1800s two types of peppered moths in Britain
Dark colored moths
Hunted by predators often
Easy to see from contrast of color of moth to color of tree
Light colored moths
Light colored moths were able to survive predators
Due to camouflage provided by white trees
Industrial revolution occurred
Soot and smoke were created from machines.
Covered the trees making them black.
Dark colored moths to be better adapted to new selection pressures.
Over time dark colored moths made up 95% of peppered moth population
Darwin's finches
There were many species of finch on the Galapagos islands
In different areas finches had different beak sizes and shapes
Finches beaks were specially adapted for their environment
This allowed the finches to more easily get food
Large beak finches ate large seeds
Small beak finches ate insects
