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How Do We Know Organisms Evolve? - Coggle Diagram
How Do We Know Organisms Evolve?
Evolution
4 Main Ideas About Evolution
Variation in Populations
Each organism will have a slight variation from each other
Inherited Traits
Traits will be inherited from an organism’s parents
Offspring Compete
Offspring will compete with each other for limited resources
Survival of the Fittest
Organisms with the best genes will survive while those with subpar genes will die
Evidence for Evolution
Fossil Evidence
Fossils show the fossilized bones of an organism that has slowly evolved
Molecule Evidence
Shows a specific sequence of DNA and compares it with another organism’s DNA sequence. The more similarities there are, the closer they are related to each other.
Anatomical Evidence
Specific structures such as vestigial structures can give us hints about what type of organism an organism descended from
Biogeography
Shows the spread of an organism around the world which shows their relatedness
5 Fingers of Evolution
Bottleneck Effect/Small population size (pinky finger)
A population can shrink and if it shrinks, then chance can take over.
Nonrandom mating (ring finger)
If organisms choose a mate based on their appearance or location, then the frequency will change.
Mutations (middle finger)
If a new gene is added through mutation, it can affect the frequency.
Gene flow from emigration/immigration (pointer finger)
If new individuals move to a new location, then the frequency will change.
Adaptations (thumb)
The genes of individuals that are not adapted for their environment will eventually be replaced by genes that are.
Micro vs Macro Evolution
Microevolution
Microevolution is a small change that occurs over a short period of time.
Four mechanisms allow this to happen: mutation, gene flow (migration) natural selection, genetic drift.
Mutation - change in a DNA sequence, usually occurring because of errors in replication or repair. Mutation is the ultimate source of genetic variation.
Gene flow (migration)- The movement of individuals between populations that bring new genetic variations with them.
Natural selection-differential survival or reproduction of different genotypes in a population leading to changes in the gene frequencies of a population.
Genetic drift- usually happens in small populations, but gene frequencies change as a result of a random occurrence (such as a storm, wildfire, tornado, drought, etc) that wipes out most of the population.
Superbugs
Bacteria that are resistant to certain antibiotics
Shows evolution occurring as the bacteria with preexisting resistance will survive and reproduce while those without the resistance will die
Horizontal Gene Transfer
Bacteria are able to trade parts of their DNA with each other in order to gain more variations.
Macroevolution
Macroevolution is evolution over geologic time, and allows for a new species to develop due to isolation
Geographical Isolation
Temporal Isolation
Behavioral Isolation
Speciation
Species - a group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding.
New species form by speciation, in which an ancestral population splits into two or more genetically distinct descendant populations.
Speciation occurs when the two groups that came from the original population can no longer reproduce and collect too many changes in their genome so that they become distinct.
Skin Color
There are a variation of skin tones due to the amount of UV radiation an individual’s ancestors recieved.
Darker skin is found near the equator which recieves the most amount of UV radiation which shows that more melanin is present so it reflects a lot of the UV light which can lead to a deficiency of vitamin D and therefore protects the folates and nucleus of the skin cell.
Lighter skin is found away from the equator as they receive less UV radiation which shows that there is less melanin present so it absorbs a lot of the UV light in order to synthesize it into vitamin D and it won’t damage the folates or the nucleus of the skin cell.