Evolution. We are going to find out about;

Transcription

1 EVOLUTION

2 Evolution We are going to find out about; How life on Earth may have begun and is evolving How scientists developed an explanation for evolution How specific animals evolved Analogie und Homologie

3 The Variety of Life It is often easy to spot the differences between living things. But there are also lots of similaries; Most living things use DAN to pass on information. Human skin cells and cells in a butterfly use the same chemical reaction to make pigment.

4 Classifiaction Scientists use the similarities between living things to put them into groups.

5 What makes a species? Scientists define a species as a group of organisms so similar that: They can breed together Their off spring can also breed (fertile) Example; Horses and donkeys can breed together to produce offspring mules. But mules are infertile. So horses and donkeys are different species.

6 Variation Variation in a species is very important (we ll learn more about this later). There are genetic (male and female) and environmental variations (short and long hair). Some variations like skin colour can be both genetic and environmental variations.

7 The evidence for evolution Most scientists agree that life on Earth started from a few simple organisms. This explains why there are so many smilarities amongst living things. These simple organisms evolved over time to produce all the living things we have on Earth today. Complete the worksheet Die Erdzeitalter use page 18/19 as reference.

8 Evidence for evolution? Fossils are made from dead bodies of living things. Most fossils found are from extinct species. Conditions have to be just right for fossils to develop. There are gaps in the fossil record. Fossils help us to develop a picture of how evolution may have happened.

9 Brückenformen Transitional Form Complete worksheet Kriechtier, Archaeoperyx und Vogel in Vergleich Use page 112/113 Two years after Charles Darwin published his work on evolution the first fossil of an Urvogel / Archaeopteryx was discovered. The Archaeopteryx lived in the late Jurrasic period, 150 million years ago. It has features similar to both the modern bird and also the reptile/dinosaur speices This is why it was regarded as a transitional form It is used as proof for evolution and Darwin s theory of evolution.

10 Evidence for change now... Evolution didn t just happen during the prehistoric times. Evolution is ongoing. 2 different types... Selective breeding: Choosing organisms with certain characterists and mating them to try to produce off spring that have the desired characteristics. E.g Labradoodle Producing disease-resistant wheat by crossbreeding wheat plants with disease resistance and wheat plants with a high yield. Natural Selection When certain variants of a species are better suited to their environment and are more likely to survive and breed. E.g. head lice in the UK. A variety were resistant to the poison and survived. UK now has a form of super lice

11 Natural Selection Read the articles of natural selection in giraffes and complete the worksheet. Warum haben die Giraffen einen langen Hals Use page 116 to help

12 Charles Darwin Most scientist now agree that evolution happens, but this wasn t always well accepted. Charles Darwin and his ideas were a break through in persuading people about evolution. Darwin explains how Evolution could happen through natural selection Darwin was always interested in plants and animals. At the age of 22 he set out on a 5 year journey aroung the World on the Beagle.

13 Charles Darwin Journey of the Beagle The Beagle stopped at many places. At each stop Darwin looked at different species and made lots of observations. At the Galapagos islands he noticed variation in the wildlife. He noticed key differences in the finches in his observations. The finch varieties had different shaped beaks. The beaks were adapted to eat the food available of the different islands. Complete worksheet on Charles Darwin. Use page 116