3.2 Origins of Biodiversity Significant Idea: Evolution is a gradual change in the genetic character of populations over many generations, achieved largely through the mechanism of natural selection. Environmental change gives new challenges to species, which drives the evolution of diversity. There have been major mass extinction events in the geological past. Starter: Create a spider diagram with the word Evolution. In the middle. Write everything you know around this topic around the spider diagram. Charles Darwin Alfred Russel Wallace

3.2.U1: Biodiversity arises from evolutionary processes Biological evolution is the process of change and diversification of living things over time, and it affects all aspects of their lives--morphology, physiology, behaviour, and ecology. In order for evolution to occur three things are necessary: Variation – every individual is unique, you have unique set of DNA which means that you differ from others of the same species. Natural Selection – various factors make certain individuals fitter. This means they have more chance of having offspring. Heredity – the characteristics that made you fitter need to be coded in your DNA, and need to passed onto your offspring. Underlying these changes are changes in the hereditary materials. Hence, in genetic terms, evolution consists of changes in the organism's hereditary makeup. During the process of evolution - the history of life on earth - both processes speciation and (mass)extinction were very common.

In order for evolution to occur three things are necessary: 3.2.U1: Biodiversity arises from evolutionary processes In order for evolution to occur three things are necessary: Variation – every individual is unique, you have unique set of DNA which means that you differ from others of the same species. Natural Selection – various factors make certain individuals fitter. This means they have more chance of having offspring. Heredity – the characteristics that made you fitter need to be coded in your DNA, and need to passed onto your offspring.

Within one species there is a great amount of genetic variation 3.2.U2 Biological variation arises randomly and can either be beneficial to, damaging to, or have no impact on, the survival of the individual Within one species there is a great amount of genetic variation

3.2.U3 Natural selection occurs through the following mechanism: 1. Within a population of one species, there is genetic diversity, which is called variation. 2. Due to natural variation, some individuals will be fitter (more suited) than others. 3. Fitter individuals have an advantage and will reproduce more successfully than individuals who are less fit. 4. The offspring of fitter individuals may inherit the genes that give that advantage.

Heredity The characteristics must be able to be passed down to the next generation. This is only possible if they are coded for within your DNA.

Evolution does not occur over one generation. 3.2.U4 Natural selection contributes to the evolution of biodiversity over time. Evolution does not occur over one generation. This is why many find it hard to accept evolution. It takes many generations for large changes to be seen.

3.2.U5 Environmental change gives new challenges to species: those that are suited will survive, and those that are not suited will not survive.

3.2.U5 Environmental change gives new challenges to species: those that are suited will survive, and those that are not suited will not survive.

3.2.U5 Environmental change gives new challenges to species: those that are suited will survive, and those that are not suited will not survive.

3.2.U6 Speciation is the formation of new species when populations of a species become isolated and evolve differently from other populations. New species arise when populations of a species become isolated and evolve differently from other populations.

Using you computers(and text books) to answer the following questions. 3.2.U7 Isolation of populations can be caused by environmental changes forming barriers such as mountain formation, changes in rivers, sea level change, climatic change or plate movements. The surface of the Earth is divided into crustal, tectonic plates that have moved throughout geological time. This has led to the creation of land bridges and physical barriers with evolutionary consequences. Using you computers(and text books) to answer the following questions. Give 5 different ways physical barriers can be formed and give real world examples. What is plate tectonic theory and what evidence is there to support it? How does plate activity influence evolution and therefore biodiversity?

3.2.AS1 Explain how plate activity has influenced evolution and biodiversity Explain how the mechanisms of evolution have led to an increase in biodiversity in the past. (6) genetic variation occurs in populations (due to mutation/recombination); natural selection occurs in populations; those that are most fit to survive in the local conditions survive, and pass on their genes to future generations; speciation occurs due to isolation which may be geographic/reproductive; as species are isolated they evolve differently; isolated populations may be subject to different natural selection; eventually isolated populations are sufficiently different that they are unable to produce fertile offspring; thus the number of different species/species diversity increases over time; e.g. speciation occurred as plates diverged and individuals were isolated; as plates moved and areas experienced new climatic conditions species adapted over time to new conditions; barriers formed between ecosystems e.g. through fold mountains as plates converged, leading to speciation;

3.2.U9 Mass extinctions of the past have been caused by various factors, such as tectonic plate movements, super-volcanic eruption, climatic changes, and meteorite impact – all of which resulted in new directions in evolution and therefore increased biodiversity. Mass extinctions

3.2.U9 Mass extinctions of the past have been caused by various factors, such as tectonic plate movements, super-volcanic eruption, climatic changes, and meteorite impact – all of which resulted in new directions in evolution and therefore increased biodiversity. Mass extinctions Tectonic plate movement. Super-volcanic eruption. Climatic changes (drought and ice ages). Meteorite impact. All result in evolution moving in new directions which therefore increased biodiversity.

3.2. AS2 Discuss the causes of mass extinctions. Long-term increase/period of stability for several hundred million years/ equilibrium?/major decline around 200 million/several smaller extinction periods [1]; possibly due to catastrophic events/changes in environment causing mass extinctions [1]; long-term increase possibly due to increase in diversity of environment, e.g. as land colonised by plants [1].