Stages
3,500,000,000 - Now
1.First Bacteria (prokaryotes)
2.First cells with Organelles (eukaryotes)
3.First multicellular organism (Algae, Seaweeds, sponges)
4.First Fish
5.First Land Plant and Fungi
6.First Amphibians, Reptiles and insects. Most of the land was covered in Fern which then turned to Coal.
7.First Mass extinctions of life forms (The Permian Extinction)
8.Dinosaurs evolve
9.First Birds and mammals
10.First Flowering plants.
11. Second Mass extinction (The Dinosaur extinction)
12.First Modern Mammals
13.First grasses
14.First Hominids
15.First Homo sapiens evolve and so do Neanderthals
16.Humans Colonise masses of land
17.Neanderthalts die out leaving homo sapiens as the only human species
18.Agriculture Begins
Key points
Individuals in a species show a wide range of variation.
This variation is because of differences in genes.
Individuals with characteristics most suited to the environment are more likely to survive and reproduce.
The genes that allowed the individuals to be successful are passed to the offspring in the next generation.
Individuals that are poorly adapted to their environment are less likely to survive and reproduce. This means that their genes are less likely to be passed to the next generation. Given enough time, a species will gradually evolve. The evolutionary connections between biological groups can be illustrated in a tree of life diagram.
Evidence to back up the Natural Selection Theory
Microorganisms such as bacteria and viruses reproduce very rapidly and can evolve in a relatively short time. One example is the bacterium E coli. Its DNA can be damaged or changed during replication, and most of the time this causes the death of the cell. But occasionally, the mutation is good for the bacteria. For example, it may allow resistance to an antibiotic. When that antibiotic is present, the resistant bacteria have an advantage over the bacteria that are not resistant. Antibiotic-resistant strains of bacteria are an increasing problem in hospitals.
Why Darwin’s theory was not accepted at the time
Darwin's ideas caused a lot of controversy, and this continues today. They can be seen as conflicting with religious views about the creation of the world and the creatures in it.
Darwin Vs Religion
Today we link evolutionary science with scientists such as Charles Darwin who wrote 'On the Origin of Species' in 1859. He argued that life began with very simple cells and later developed into what we see today. He said that natural selection was one of the major mechanisms driving evolution.
Darwin upset many people with his views and even some respected scientists such as Philip Gosse argued that the fossils had been placed there by God deliberately to fool people.
Some Christians found Darwin's theory a threat to their faith because it appeared to challenge the authority of the Bible. If the Bible was wrong on this matter, might it be wrong on other things too?
