Evolution - Introduction to Evolution

Evolution

A gradual process where a living thing changes to a different and typically more complex form.

Evolution by Natural Selection

Organisms best suited to their environment will be more successful at passing on their traits to the next generation.

Who proposed the theory called “Evolution by Natural Selection”?

Charles Darwin

Miller-Urey Experiment

A famous chemistry experiment where they mixed gasses that were thought to be present in the atmosphere of the early, prebiotic Earth.

Microevolution

The process where organisms change in small ways over time.

Example of microevolution

Mosquitoes that can’t be killed by pesticides; when these mosquitoes reproduce, there will be an increase in their population.

Macroevolution

Larger evolutionary changes that result in a new species.

Two main causes of macroevolution

1. Macroevolution (? double check lol) occurring repeatedly over a long period of time.
2. The result of a drastic environmental change (natural disasters)

Where does evidence for macroevolution come from?

1. Examination of fossils
2. Comparing living things

Name some examples of environmental challenges that hinder the ability of organisms to survive

Severe weather, famine, competition against other organisms for limited resources. If organisms can survive such challenges, they are able to produce offsprings, explaining how some species survive while others go extinct.

Adaptation

A structural, behavioural, or physiological process that helps an organism survive in a specific environment.

Name an example of a structural adaptation

Camouflage

Name an example of a physiological adaption

Hibernation

Mimicry

A structural adaptation where a harmLESS species resembles a harmFUL species in colouration or structure. (Ex. Moths mimicking owls, which are predators)

How do adaptations develop?

* The result of gradual, accumulative changes helping an organism survive and reproduce.
* Random, inheritable mutations in DNA
* Variations

Variations

Structural, functional, or physiological differences, but not ALL variations become adaptations. (Ex. Black peppered moths)

Genetic Variation

The difference in DNA among individuals and populations.

* Occurs through sexual reproduction, where different alleles are inherited.