Evolution

Creation Theories

The variety of life http://www.youtube.com/watch?v=yDdaStk5SEM http://www.youtube.com/watch?v=HStl89NXdHQ&feature=related

Linnaeus

Fossils

Fossil Hunters

Anaximander Anaximander – a Greek scholar from the 5th century BC tried to explain where life came from without the use of supernatural He postulated life on land came from the sea. He suggested climate change as a stimulus He was aware of the existence of fossils

18th/19th century thinkers Charles Linnaeus Jean Baptiste Lamarck Thomas Malthus Sir Charles Lyell Charles Darwin Alfred Russell Wallace

Background Fossils – it was popular to collect them and it was apparent that sea creatures were being found up mountains etc. People were beginning to understand that geological change was slow Geologists could see patterns in the strata of rocks This was the Age of Enlightenment: people were questioning accepted wisdoms The diversity of life was being appreciated Factors affecting populations size were beginning to be grasped.

1st Theory JB Lamarck (note he’s French)

What is wrong with Lamarck’s theory? Give examples of how you know it is wrong. What other information do you know that might be relevant?

Charles Darwin Publication prompted by the work of Alfred Wallace in Malaysia

Dawin’s finches

Darwin’s influences Thomas Malthus Theory of population ‘The struggle for existence’ we call it competition Charles Lyell Principles of Geology The age of the earth and the slow changes of geological time Fossils

Darwin’s Key concepts Survival of the fittest (attributed to Herbert Spencer): only individuals with the necessary features will survive in an environment. Natural Selection There is variation Variation leads to differences in success and therefore amount of young produced The traits of the more successful are inherited by their young Some traits become more prevalent in population – a subtle change over time occurs

Problems at the time 1. Creationism 2. No one knew the mechanism, i.e. genes 3. The immense age of the earth was not an accepted fact. 4. The slow progress of evolution in most species

Evidence Microevolution House sparrows from Europe have adapted to US harsh winters Rabbits from southern Europe have adapted to cold in UK – took about 400 years Insects and rats have evolved resistance to pesticides Bacteria have evolved resistance to antibiotics

Peppered moths How does this demonstrate fitness?

Sex Sexual selection Choose the strongest fittest mate to breed with Males of many species demonstrate their fitness with ridiculous shows of colour etc. http://www.youtube.com/watch?v=nS1tEnfkk 6M

Adaptation Features develop that fit the habitat

Coevolution Species develop alongside each other Flowering plants and flying insects http://www.youtube.com/watch?v=FiwkJui2m h0 http://www.youtube.com/watch?v=gEcv3dBu Oe4

Missing links in fossil record Postulated and gradually being filled Ida an early fossil primate linking the different primate groups

Missing links Archaeopteryx – showing features of birds and dinosaurs

Summary Competition controls population sizes Animals adapt to their environment – best adapted survive and pass on their genes. Poorly adapted die out Survival of the fittest Sexual reproduction leads to variation If the environment changes different features may be more desirable and in turn individuals possessing these become more successful natural selection This leads to changes in populations called evolution In very stable systems creatures become increasingly specialised.

Where are we now? Theory Mechanisms Challenges Evolution is universally accepted by scientists The alternative Intelligent design has no serious scientific rigour Theory The role of genes is increasingly fully understood Mechanism of survival of the fittest and natural selection underpin our understanding of the interactions of all life on earth. Mechanisms Scientists still debate the exact mechanisms Some believe it is always slow, others that certain situations lead to rapid changes Has been abused by extreme political organisations to justify racist policies. Challenges

Creationism is not an alternative theory – it is a belief to which you are entitled

For end of partial 2 You need to be able to give an overview of your Scientific Ideas talk You can present this to me in your groups. It would be helpful to have the outline or title of the majority of slides to be included You need to know the names of the main protagonists You need to be able to explain a couple of points It does not have to be perfect to get 100% I need to feel you’ve done some work and know what you’re talking about.