Adaptation of Living Things

Study Notes

Living things are adapted for survival in their habitats through special features or developed better features over time.
Examples of adaptations include an African elephant's large ears to keep cool in a hot habitat, and a polar bear's thick fur to keep warm in a cold habitat.
Plants also adapt to their environments, such as a cactus's shallow roots and water-storing stem to survive in the desert.

Mutations are permanent changes in the DNA sequence.
They can be neutral, positive (advantage), or negative (disadvantage).
Environmental factors, such as radiation and chemicals, can increase the rate of mutation.
Examples of mutations include:
- Positive mutation: plants developing resistance to bacterial and fungal infections.
- Negative mutation: cancer, caused by mutations in genes that regulate the cell cycle.
- Neutral mutation: white fur of the Kermode (Spirit) bear, which is usually black.

Evolution is explained by Darwin's basic theory of natural selection.
The theory focuses on how variations benefit individuals to survive environmental changes, predation, or competition.
Individuals with successful variations produce more offspring, passing the variation on to the next generation.
This process allows the population to evolve with the successful variation.

Charles Darwin issued a book about his scientific theory of natural selection called On the Origin of Species in 1859.
Darwin's theory explained how every living thing is connected in a family tree that stretches back billions of years to the beginning of life on Earth.
One of Darwin's discoveries was the identification of fourteen different species of Finches in the Galapagos Islands, each with adaptive beaks for their eating habits.
Examples of adaptive beaks include:
- Strong and sturdy beaks with a chisel-like tip for drilling holes in wood (woodpecker).
- Shorter, stouter beaks for eating seeds found on the ground.
- Long, pointed beaks for picking seeds out of cactus fruits.