Classwork activity

Seite 1

Where do species come from?

Biological evolution by natural selection.

This chapter explains how we end up with around 100 million species. The idea that life changes over time has been around for a very long time, but the naturists Charles Darwin and Alfred Russel Wallace, were the first to propose the natural selection theory, which explains how we've evolved through out the years.

The Fossil Record

Much of the things we know nowadays are due to the things we've observed from fossils, leaving evidence about life's evolution, we have something called the fossil record but it only represents around 1% of life forms back then. The first step in this process is the development of genetic variability.

This occurs through mutations (random changes in the structure of DNA. An adaptation or adaptive traits is any heritable traits that enables an organism to survive through natural selection. Traits must also lead to differential reproductions, which enables individuals to produce more offspring . Human have evolved and survive scientists attributes this success to three adaptations strong apossable thumbs, walk upright and a complex brain.