Process of Natural Selection Foldable Natural Selection = NS GLE GLE SPI SPI

NS – individuals better adapted to their environment survive and reproduce more successfully than less well-adapted organisms do. GLE GLE SPI SPI

Overproduction egg sac GLE GLE SPI SPI

Overproduction: organisms in a populationproduce more offspring than their environment can support. Many die through predation or starvation GLE GLE SPI SPI

Example: Tarantula’s egg sac holds 500 to 1,000 eggs. Some eggs survive and develop into adult spiders and some die. GLE GLE SPI SPI

Photography of Egg sack - Poecilotheria pederseni

The moulting process

Genetic Variation Within A Population GLE GLE SPI SPI

Variation: Differences in a population of organisms of the same species. Variations/Genetic Adaptations - passed to offspring from parents through genes/alleles. GLE GLE SPI SPI

Example: Every individual has its own combination of traits. Each tarantula is similar, but not identical, to its parents. GLE GLE SPI SPI

Struggle to Survive (adaptation) GLE GLE SPI SPI

Newly inherited traits help organisms survive and reproduce in their environment. Some variations are favorable and help organisms compete to survive and reproduce. GLE GLE SPI SPI

Example: Some tarantulas have traits that make it more likely they will survive. better able to fight off predators GLE GLE SPI SPI

Adult female Brachypelma smithi, showing a bald patch after kicking hairs off of her abdomen.

Successful Reproduction (natural selection) GLE GLE SPI SPI

Over time, offspring with helpful variations increase and become a larger percentage of the population. The organisms with favorable variations become plentiful. The ones without favorable variations become rare or extinct. GLE GLE SPI SPI

Example: Tarantulas best adapted to their environment are likely to survive and reproduce. Offspring may inherit traits that help them survive. GLE GLE SPI SPI