From Darwin’s collection of evidence he created his theory of evolution by NATURAL SELECTION (sometimes referred to as t

2. From Darwin’s collection of evidence he created his theory of evolution by NATURAL SELECTION (sometimes referred to as the survival of the fittest).

3. This theory is based on six points: 1. Overproduction • More offspring are produced than can survive. • Examples: Fish that lay millions of eggs, Sea turtles. Based this belief on Thomas Malthus ‘s writings on population survival.

4. Example of overproduction: Sea Turtles - lay from 70 to 190 eggs (depending on the species). Only about 1 out of 100 survive.

5. 2. Competition • Because of overpopulation, organisms of the same species, as well as those of different species, must compete for limited resources such as food, water, and a place to live. • Interspecific competition – between different species • Intraspecific competition – between the same species

6. 3. Variation • Differences occur among members of the same species. No two individuals are exactly alike. • These variations are passed onto the next generation.

7. 4. Survival of the Fittest • Natural selection. • Individuals in a species with traits that give them an advantage are better able to compete, survive and reproduce. Others die off without leaving offspring.

8. 5. Speciation • Origin of new species. • Over numerous generations, new species arise by the accumulation of inherited variations. • When a type is produced that is significantly different from the original, it becomes a species. • A species can reproduce successfully with its own kind.

9. 6. Adaptation • The accumulation of characteristics that improve a species’ ability to survive over long periods of time. • Allows organisms to become better suited to their environment.

10. Adaptations There are 3 broad categories of adaptations: • Physiological • Behavioural • Structural

11. 1. Physiological • Physiological adaptations involve what is going on inside the body. • Example: - hibernation of bears. - cow’s ruminant digestive system. - pesticide-resistant insects. - antibiotic resistant bacteria.

12. 2. Behavioural • An organism’s behaviour may provide it with a better chance of surviving and reproducing. • Example: - Storage of nuts by squirrels. - Plants bending towards light. - Animals “playing dead”. - migration of Canada geese.

13. Staying in the shade is a behavioural adaptation common in nature.

14. 3. Structural • Structural adaptations involve an organisms anatomy. • Examples: - Webbed feet of ducks for swimming. - talons on eagles for grasping. - Camouflage. This can be used to benefit both predator and prey. - Mimicry.

15. Angler Fish

16. Example of camouflage - Phasmatodea (walking stick insect)

18. Example of mimicry - moth resembles owl to “scare off” predators.

19. Adaptations do not always fit neatly into just one of these categories. They may be in combination. • Example: • Elephant’s ear.

20. Advantageous adaptations give an organism a competitive edge in the struggle for food, space, ability to reproduce and the ability to avoid predators. • Habitats also change, so what was once an advantage may one day become a disadvantage. • Successful (“the fittest”) organisms are the ones with adaptations that allow them to survive and to reproduce.

21. Do not confuse adaptation with: Acclimatization – when an organism becomes accustomed to changing environmental conditions. It is not the product of natural selection. There is no change in the gene pool of the species. Example: getting used to cold weather in winter.