1. Lesson 6.1 Objectives  How scientists use fossils to learn about the history of life  How organisms evolved more complex forms over time  About mass extinctions

3.  Fossil Record – information provided by fossil records and their location.  Fossil record lets scientists identify periods during which different species existed.

4.  Cyanobacteria – earliest known organisms in the fossil record ◦ Contained chlorophyll and used photosynthesis to make sugars from carbon dioxide ◦ The bacteria produced oxygen as a by-product of photosynthesis

5.  The first eukaryotes were single-celled  The oldest eukaryotes are from algae that lived 2 billion years ago.  600 mya the first multicellular animals (jelly-fish like) evolved.

6.  Bacteria and algae – first life forms on land  Primitive insects – first land-dwelling animals

7.  The loss of all the members of a species Mass extinctions – several periods of huge numbers of species have become extinct in a very short time Permian extinction – the largest mass extinction in Earth’s history. Cretaceous Extinction – dinosaurs extinction

9. Lesson 6.2 Objectives About early ideas and observations on evolution How Darwin developed his theory of natural selection How new species arise

10.  Refers to the process through which species change over time

11.  French naturalist  Proposed that during the organism’s lifetime, they change in response to their environment  Example – giraffes long neck

14.  British naturalist  He published a book about a voyage in Galapagos island  Beagle – the name of a British navy ship  The book described his observations about how evolution works

15. Galapagos Island

16. Darwin observe several types of:  Tortoises  Finches

17. According to Darwin:  Individuals that are best suited to their environment survive and reproduce at a higher rate than other members of species in that environment

18.  Overproduction  Variation  Adaptation  Selection

19.  Population – is a group of similar species  In nature, organisms reproduce a lot but not many can survive.

20.  Variation or differences among individuals  Genetic variation happens when offspring get a mix of chromosomes from both parents

21.  An inherited trait that gives an organism’s an advantage in its particular environment

22.  Individuals that adapted in their environment have a good chance of survival.  The adaptive trait will be passed on to their offspring.  Overtime, the useful trait will become more common in the population

23.  The evolution of a new species from an existing species.  Isolation is the key factor that leads to speciation

24. Lesson 6.3 Objectives How populations increase and decrease in size What factors affect population size and survival How species can become extinct

25.  All populations have the ability to grow rapidly over time  Populations tend to remain about the same size

27.  Population increase through births and immigration  Immigration – the movement of individuals into a population

29.  Emigration – the movement of individuals out of the population  Limiting factors: RESOURCES COMPETITION PREDATORS DISEASE CATASTROPHIC EVENTS

30. Lesson 6.4 Objectives How scientists develop theories About the evidence Darwin used to support the theory of natural selection About additional evidence most scientists use today

31.  Theory – is an explanation of natural phenomena based on a wide range of scientific evidence  Ancestor – is an early form of an organism from which later forms descend  Vestigial Organs – are structures that were fully developed in ancestral organisms but are reduced and unused in later species

32.  Fossils provided evidence that species in the past were very similar to species living in Darwin’s time

33.  Vestigial Organs - similar structures with different functions

34.  Similarities in Development

35.  DNA contains the information that organisms need to grow and to maintain themselves.  When organisms reproduce, they pass on their genetic material to their offspring