science gcse core, additional and triple science powerpoints

1. B3 Life on Earth Route map Over the next 12 lessons you will study : Friday 21 October 2011 B3.1 The variety of life B3.2 How does evolution happen B3.3 Evidence for change now B3.4 The story of Charles Darwin End of module test B3.5 Theories of evolution B3.6 The origins of species B3.7 The mechanism of inheritance B3.8 Where did life come B3.9 Sensing the outside the environment B3.10 Human evolution B3.11 Extinction B3.12 Human activities causing extinction B3.13 What’s on our doorstep

3. B3.7 The mechanism of inheritance Decide whether the following statements are true or false: Introduction: A gene is a region of DNA that controls a hereditary characteristic. Humans are estimated to have about 31,000 genes. Different forms of the same gene are called alleles. Humans carry different alleles for one particular trait for example eye colour. When there are two different alleles for one trait, one is usually stronger or dominant to the other. All genes are arranged in a double helix, one strand is maternal, the other paternal. Genes change due to mutations and these changes can cause variation in species. Some of these variations can make an individual more successful and hence more like to pass on their genes to the next generation. Extension questions: 1: Explain two ways that a mutation in a gene can arise ? 2: Explain how mutations in an individual genome causes variation ? 3: A well know mutation is the so called ‘Albino human’ where the skin lacks any pigment at all. Explain why Albinos are at risk of early death from skin cancer ? 4: Some mutations cause trivial changes in an organisms characteristics like eye colour or nose shape. Give three other examples where mutations cause these types of changes ? Know this: a: Know that genes code for characteristics like eye colour. b: Know that genes are passed form mother and father to offspring. Friday 21 October 2011

4. B3.7 a Look at the photograph and information and answer all the questions: Every plant or animal is the result of reproduction, and all organisms reproduce. Sexual reproduction needs two individuals of the opposite sex. During sexual reproduction, an embryo is formed when an egg carried by the female is fertilized by the male sperm. The embryo has a unique set of genes inherited from the mother and father. Pick three traits from the list in the diagram below left…decide which of these traits you have inherited from your mother or your father ? Which trait for a) hair colour and b) eye colour is most common in the UK ? Looking at the traits of a mother and father, can you always predict the traits that the children will inherit ? Traits Eye colour Skin colour Hair colour Height Blood group Hand span Tongue roller Freckles Attached lobes Fertilisation Egg Sperm 1 set of DNA 1 set of DNA Zygote 2 sets of DNA Newborn Key concepts

5. B3.7 b Look at the photograph and information and answer all the questions: Each human has a unique set of genes that code for all our traits. This is called their genotype and it cannot be changed. A humans’ phenotype is what they look like and is the result of a person’s genotype and their environment. For example, a human cannot change their blood group, but they can change their hair colour by dying it. A study showed that the weight difference between twins was less than the weight difference between siblings, do these results suggest that genes control our weight ? Explain why identical twins look more alike when they are newborn when compared to how they look at 20 ? List using a table a) three traits that you could change and b) three traits that you could not change ? Key concepts

6. B3.7 c Look at the photograph and information and answer all the questions: Some features like height and hand span show continuous variation, and some features like eye colour show discontinuous variation. Human height ranges from that of the shortest person to that of the tallest person. If you record the heights of a group of individuals and draw a graph of your results, it has a bell shaped distribution: List three factors than can affect the eventual height a human will be ? Looking at the graph opposite, how might clothes shops who sell trousers, gloves or shoes use this data to decide how many of each size to make, stock and sell ? In 1950, the average female height was 158 cm, in 2009 it is 165 cm…explain what has caused this increase in female height ? 155 165 175 185 % abundance Height (cm) Key concepts

7. Key concepts B3.7 d Look at the photograph and information and answer all the questions: There are two alleles for height: tall and short. Using the information in Mendel's original data which allele is recessive, which is dominant ? If both alleles for height (tall and short) were co dominate what would the results of an F 1 cross be like in the F 2 generation ? Mendel’s work in peas Tall dwarf Tall Tall Tall Tall Tall dwarf Gregor Mendel, in 1850s was the first to study the transfer of traits from parent to offspring. He selected peas. He crossed pollinated pure bred tall and pure bred short pea plant. He called this the P or parental generation. In the first generation, he got all tall plants. This generation was called the first filial or F1 generation. Then the plants from F 1 generation were self-pollinated and the next generation was called the second filial or the F2 generation. In this generation, the ratio of tall to short plants was found to be 3:1. P F 1 F 2

8. Key concepts B3.7 e Look at the photograph and information and answer all the questions: List three traits that are dominant in humans and three traits that are recessive ? Mendel’s work in peas Tall dwarf Tall Tall Tall Tall Tall dwarf Gregor Mendel didn’t just use one trait to investigate the mechanism of inheritance from parent to offspring. He another experiment, he crossed pollinated pure bred purple flowered peas with pure bred white flowered pea plant. Again he called this the P or parental generation. In the first generation, he got all purple flowered plants. This generation was called the first filial or F 1 generation. Then the plants from F 1 generation were self-pollinated and the next generation was called the second filial or the F 2 generation. In this generation, the ratio of purple to white flower plants was found to be 3:1. P F 1 F 2 There are two alleles for flower colour: purple and tall. Using the information in Mendel's original data which allele is recessive, which is dominant ?

10. B3.8 Where did life come from ? Extension questions: 1: Explain why bacteria evolved before multi-cellular organisms ? 2: How long ago did life begin on Earth ? 3: Explain how life could have been brought to earth by a comet. 4: What is meant by multi-cellular? 5: Write down two advantages of being multi-cellular when compared to a simple bacteria ? Know this: a: Know when and how life began on Earth and that the habitats on earth then were very different to today’s habitats. b: Know that life began by simple chemical replicating themselves with a bi-lipid membrane or cell membrane Friday 21 October 2011 Introduction: Life on Earth began about 3.5 billion years ago. Most living things on Earth today contain DNA. This is the molecule that can copy itself and is a set of instruction that control our characteristics. All living and extinct organism on Earth evolved from the first simple organisms. Simple organisms developed from molecules that could copy themselves. Biologists disagree about the origin of these molecules. Some believe that they were produced by environmental conditions on Earth at that time (under the ocean floor). Others believe they came from elsewhere in the Solar System via a meteorite or comet. What is clear is through evolution and gene changes all living things on Earth are suited to survive in their habitat.

11. Key concepts B3.8 Look at the photograph and information and answer all the questions: One theory is that life started at the bottom of the oceans. Hot water springs on the ocean floor contain dissolved minerals. When the hot water from the springs meet the cold seawater, minute bubbles of iron sulfide, filled with a solution of different chemicals, are formed. These bubbles act like cooking pots forming a thin layer of fatty protein and the first cell membrane. Why do scientists think that life began at the bottom of the ocean floor? Are these single cell organisms or multi-cellular organisms? What is the other scientific idea on how life began on Earth?

12. Key concepts B3.8 Look at the photograph and information and answer all the questions: Another theory is that life may have begun on comets. Scientists have shown that amino acids may form from ammonia and other molecules under certain conditions of energy from lightning or ultraviolet light. Out in their distant orbits, comets are exposed to the kind of cosmic radiation which provides the energy needed to form these long, complex molecules, essential for life to begin. Comets contain ice, dust and water and other chemicals. Explain how life could exits in this icy object ? Scientists have analysed chemicals in the tail of a comet using a space probe and found organic molecules. Does this add evidence to life existing in comets ? Why do scientist say that wherever life started water must have been present ? Chemicals DNA Bacteria

13. B3.8 Plenary Lesson summary: solar copy conditions 3500 Friday 21 October 2011 From single cell bacteria, multi-cellular organisms evolved millions of years later. They became specialised in many different ways. Gradually the huge variety of life evolved over millions of years. Over that time some organisms became extinct as a result of destruction of habitat, hunting, competition for food & mates and disease. How Science Works: Research into how the nervous and hormonal systems coordinate the human body. Look into their similarities and differences Preparing for the next lesson: The first living things were molecules that could _____ themselves. They first appear on Earth about _____ million years ago. Some scientists think that these molecules came from somewhere else in the ______ system. Another theory is that life started on Earth. At that time the ____ might have been just right to produce these molecules Decide whether the following statements are true or false : False True 3: Most living things on Earth today contain DNA which can copy itself ? False True 2: There are billions of theories about how life began ? False True 1: Life began 300 million years ago?

17. Key concepts B3.9 b Look at the photograph and information and answer all the questions: All involuntary actions that support life (i.e. heart rate, blood pressure & hormone levels) are coordinated by your nervous system. This coordination can be divided into two different parts: Parasympathetic and sympathetic parts of your nervous system. One responds (sympathetic), the other calms (parasympathetic) Which part of the system causes a) increases in your heart rate and b) when you are asleep which system shuts down your key organs ? During an asthma attack which part of your nervous system is responsible for constricting your airways ? If there is no pupil reflex after a traffic injury what does this tell you about the brain ? The nervous system

18. B3.9 Plenary Lesson summary: effector neurons spinal nervous Friday 21 October 2011 The thyroid gland makes a hormone that controls chemical reactions in the body. If a child doesn’t get enough of this hormone, their growth will be effected. The pancreas makes insulin for the control of blood sugar. The pituitary gland makes hormones which controls all other glands. The adrenal glands (top of the kidney) make adrenaline which speeds up the heartbeat and breathing rate. How Science Works: Explore websites for evidence for human evolution. Preparing for the next lesson: In a multi-cellular organisms, their cells need to communicate. They have evolved ______ system. These are made up of nerve cell (_____) linking receptor cells to ____ cells. In humans and other vertebrates, the nervous system is coordinated by a central nervous system which include the brain and ______ cord. Decide whether the following statements are true or false : False True 3: The hormonal system has a short response period ? False True 2: The central nervous system includes the brain and spinal cord ? False True 1: The nerve cells are called neurons ?

20. B3.10 Extension questions: 1: What is a Hominid? 2: Give two ways in which big brains helped some early humans to survive. 3: Why did all the hominid species except Homo Sapiens become extinct? 4: What feature shows that animals stand on two legs? 5: The explanations of human evolution are constantly changing. Why? Know this: a: Hominids share a common ancestor. Only one species survived and evolved into Homo Sapiens. b: Big brains helped early humans to use tools, hunt and make fire. Friday 21 October 2011 Introduction: Human beings and chimpanzees share about 94% of their DNA, however we are not descended from modern apes, but we do share a common ancestor which was alive some 20 millions years ago. Hominids Australopithecines share some features with human beings: eye sockets are wide and set apart, broad nose and sinus inside front of skull. They walked on 2 legs. Habilines lived in Africa 1.6 to 2 million years ago. Fossils showed that their spines were joined to the middle of their skull, so habilines walked upright. They had big brains and made tools. They are called called Homo habilis. Different groups of humans evolved from a common ancestor. All but one of these groups died out. Only Homo sapiens (modern humans) survived (big brain). What do we know about human evolution

21. B3.10 Extension questions: 1: Human evolution made a big leap forward between homo habilis and homo erectus where humans stood upright. How was this an advantage ? 2: Give two ways in which big brains helped some early humans to survive ? 3: Why did all the hominid species except homo sapiens become extinct and why do the explanations of human evolution are constantly changing ? Know this: a: Hominids share a common ancestor. Only one species survived and evolved into Homo Sapiens. b: Big brains helped early humans to use tools, hunt and make fire. Friday 21 October 2011 Introduction: Human beings and chimpanzees share about 94% of their DNA, however we are not descended from modern apes, but we do share a common ancestor which was alive 20 millions years ago. We can trace our own evolution back about 3.5 million years starting with australopithecus afarensis, with homo sapiens replacing homo neandertalensis some 13,000 years ago It is now believed that homo sapiens succeeded because of two things a) their greater intellect and that they cooperated with other humans What do we know about human evolution Australopithecus afarensis Australopithecus africanus Homo habilis Homo erectus Homo neandertalensis Homo sapiens

22. B3.10 a Look at the photograph and information and answer all the questions: Australopithecines lived in Africa 3.5 to 4 million years ago. Lucy is the most complete skeleton found. The footprints show that they walked on two legs. So they were more like human beings than chimps and gorillas. Opposite is an artist impression form the skull and other bones found of what Lucy would have looked like, far from the modern face of homo sapiens What evidence from the Lucy’s skeleton demonstrates that australopithecines walked on 2 legs ? How did living in groups with individuals that cooperated help our survive over neanderthal man ? Do you think that man is still evolving and if so what changes will we see in the next 3 to 4 million years ? Key concepts

23. B3.10 b Look at the photograph and information and answer all the questions: DNA studies suggest that all humans today descend from a group of African ancestors who about 120,000 years ago began a remarkable journey. Scientists are trying to obtain new knowledge about the migratory history of the human species by using sophisticated laboratory analysis of DNA contributed by thousands of people from around the world. Explain how skin colour changes as you move from the equator north and what drives this change in skin colour ? Look at the map of the migration of humans do you think that White Europeans are genetically we are closer to Africans or South Americans? Explain why humans might have been force to migrate many years ago ? Human migration Key concepts

24. B3.10 Plenary Lesson summary: ancestor humans sapiens brain Friday 21 October 2011 Modern humans have two features that are different from apes: (1) bigger brains and (2) walk upright. These features helped them to survive, adapt to changes and solve problems. How Science Works: Research into how species become extinct because of changing habitats or competition for resources form other individuals. Preparing for the next lesson: Hominids are animals that are more like ______ than apes. Many different hominid species evolved from a common ______. Those with bigger _____ and who walked upright had a better chance of surviving. Gradually all hominid species, except for modern humans (Homo ________), became extinct. Decide whether the following statements are true or false : False True 3: The hole at the very bottom of the skull shows that the animal stood on 2 legs ? False True 2: The bigger the brain, the better the animal is suited to survive ? False True 1: Hominids are more like apes than humans ?

25. B3.11 Extinction Decide whether the following statements are true or false: Lesson objectives: Understand the factors which can endanger a species, possibly resulting in its extinction Understand the consequences of extinction on habitats and the biosphere We will focus on. Friday 21 October 2011 First activity: The woolly mammoth became extinct during the final decades of the last ice age. It was hunted by man and lost its habitat as the ice melted and retreat. Explain why these two pressures resulted in its extinction. Literacy: Extinction, endangered, species, pressure, change, food chain, food web, factors, endanger, habitat, environmental, changes, disease, predators and extinct. Numeracy: Currently due to changing habitats, the impact of man and other factors around 12000 different species of animals and plants are at risk of extinction. PLTS Independent enquirers Creative thinkers Reflective learners Team workers Effective participators Self managers We will focus on generating and exploring ideas.

26. B3.11 Extension questions: 1: Name three changes to a habitat which can put a species under pressure ? 2: What is meant by a) extinct and b) endangered ? 3: Name two things that plant species might compete for in their habitat and two things that an animals may compete for in their habitats ?. 4: Explain why the red squirrel has been largely replaced by the grey squirrel which is more aggressive and eats different foods ? Know this: a: Know that a changing habitat can cause extinction in animals and plants that can’t change quickly enough. b: Know that in a habitat, any quick changes in their habitat can put them at a risk (they are endangered). Friday 21 October 2011 Introduction: Fossil record show that species die out and become extinct as environment change and individuals or whole species lose their struggle for survival. Extinction means never to return back on Earth. Changing habitats, disease, lack of food or water and other animals competing for the same food source can put a species under risk of extinction. Take the dinosaurs, a huge meteorite impacted with Earth causing an overnight drop in sun light and temperature which over the period of a few years caused the extinction all dinosaurs Extinction

27. B3.11 a Look at the photograph and information and answer all the questions: There have been periods in the earth past which has seen large number of species become extinct as a result of changing environments. In modern times the primary contributor to extinctions is man because our use of natural resources and the destruction of natural habitats like the tropical rain forest. What event caused the extinction of the dinosaurs around 65 million years ago ? It is said that small mammal replaced the dinosaurs on land. Why was this important for our own evolution in time ? Man’s activities causes most extinctions now. Explain three things that we do that may endanger animals or plants ? Key concepts

28. B3.11 b Look at the photograph and information and answer all the questions: Ammonites first appeared 415 million years ago During their evolution the ammonites faced no less than three catastrophic events that would eventually lead to their extinction. The final catastrophe occurred at the end of the Cretaceous period when all species were annihilated and the ammonites became extinct. This event apparently coincided with the death of the dinosaurs What evidence tell us when ammonites first and last appeared on the Earth’s surface ? If ammonites finally became extinct around the same time as the dinosaurs how many years ago was that ? Explain how do fossils like the one picture above form ? pressure extinction Extinction of the ammonites Key concepts

29. B3.11 c Look at the photograph and information and answer all the questions: Explain which specie or species compete with giraffe for nutrients from the Acacia tree ? Explain how cheetahs are adapted to catch both zebra’s and impalas ? During a dry season, the amount of grass would be much less...explain why this would affect numbers of zebra and impala, but not giraffe ? In all habitats, primary, secondary consumers and top predators feed on more than one species of plant or animal. Furthermore, if two species relies on only one food source this will increase competition among species. A food web gives a more complete picture of how herbivores and carnivores feed and compete for limited resources. Lion Cheetah Giraffe Zebra Impala Acacia tree Grass Food chains and webs Key concepts

30. B3.11 Plenary Lesson summary: species web food extinct Friday 21 October 2011 In 1929, mink were farmed in the UK for their furs. Some escaped into the wild and some were released by animal rights groups. Minks live along rivers and streams and shelter in holes in trees and under stones. They feed on fish, birds and their eggs and small mammals such as voles. They are fierce predators. Minks have become a problem as they wiped out voles, crayfish and some birds. How Science Works: Research into how humans and their activities are reducing biodiversity in plants and animals and how the rainforest is being destroyed at an alarming rate in South America Preparing for the next lesson: A food ____ shows what eats what. Changes to one part of the food web affect other ______ in the same food web, e.g. a sudden changes in environmental conditions, other species in the food web becoming ______ and new species arriving that can compete for _____ or can cause disease can lead to a species becoming extinct. Decide whether the following statements are true or false : False True 3: Predator is an animal that kills other animals (its prey) for food ? False True 2: Habitat is the place where an organism naturally lives ? False True 1: Endangered means at risk of becoming extinct ?

32. B3.12 Extension questions: 1: Explain how humans or their activities can cause extinction a) directly or b) indirectly ? 2: Where in the world, do they use the most resources ? 3: What impact does cutting down forests like the Amazon rain forest have on an organism’s habitat ? 4: What 3 things can you do to lower your ecological footprint ? 5: What is sustainable development and given one example how we can live more sustainably ? Know this: a: know that humans or their activities can destroy habitats and interrupt complex food webs. B: Know that we can all reduce our environmental impact by using less natural resources. Friday 21 October 2011 Introduction: Over the last 100 years, the human population has doubled to about 5.5. billion people worldwide. The developed world use and consume huge amounts of natural resources. Unless we live more sustainably our impact on the biosphere will degrade our environments and cause the extinction of many thousands of animals and plants in the next 100 years. Mass extinctions could change nature’s balance and also deny us plants that may yield new medicines useful in the fight against cancers or other diseases. Human activities causing extinction

33. B3.12 Look at the photograph and information and answer all the questions: The Amazon rain forest is being cut down for land to grow crops and to harvest it hardwood tress like mahogany and teak. This destruction is happening at an alarming rate. The rainforests are also home to thousands of species and also takes out of lot of CO 2 from the atmosphere replacing it for oxygen. What encourages farmers to use the land for crops such as palm oil or wheat or corn to feed livestock like cattle ? What will happen to the quality of the soil over time once the trees are cleared ? What will happen to animals that rely on the rain forest for food and shelter ? The Amazon rain forest Cleared tropical rain forest Key concepts

34. B3.12 Look at the photograph and information and answer all the questions: Every day we all consume natural resources. You can calculate your own Ecological footprint to determine your personal impact on your environment. Biodiversity is threatened by human activity directly (hunting) and indirectly (introducing new species into a habitat or taking away a habitat) which has caused extinction of species including the Dodo and the Woolly Mammoth. Explain why humans were not responsible for the extinction of the dinosaurs ? Dodos were both used a a protein source by man and their eggs were eaten by introduced species like rats. Explain why this led to their extinction by 1700 ? Scientists say that within 50 years the Siberian tiger will be extinct. How can we prevent this form happening ? Extinction Key concepts

35. B3.12 Plenary Lesson summary: biodiversity fuel sustainable human Friday 21 October 2011 Zoos around the World are trying to conserve many top predators like tigers. In order to prevent these species form becoming extinct they have a breeding program whilst the animal is in captivity and also help to conserve the natural habitats from where they are normally live. How Science Works: Research into how scientists sample habitats and different environments for the presence of both plant and animal life. Preparing for the next lesson: The variety of species and life is called ________. People depend on other species for food, _____ and natural fibres. Biodiversity has been threatened by _____ activity directly (hunting) and indirectly (introducing new species) which has caused extinction of species. Keeping biodiversity is part of using the Earth in a ______ way. Decide whether the following statements are true or false : False True 3: Variety of life is called biodiversity ? False True 2: Destroying species' habitat is an indirect human activity that causes extinction? False True 1: Hunting is an example of direct human activity to cause extinction ?

37. B3.13 Extension questions: 1: What is meant by ‘random’ selection ? 2: What is sampling and why is it impracticable to count every individual plant and animal species ? 3: How does measuring and recording the species in a particular environment help scientist understand ways in which organisms depend on each other? 4: Explain why making a large sample are make for a more accurate survey when counting plant and animal species ? Know this: a: Know that we survey the distribution of different individual using a line transect b: Know that new habitats are colonised by different plants and animals over time. Friday 21 October 2011 Introduction: Some animals are more sensitive to pollution than others. Scientist measure and record the species found in a particular environment. This helps them understand the ways in which different organisms depend on each other. Long term monitoring is needed to decide if a species is endangered. Scientist often measure and record species by sampling, e.g. use random quadrates. Throw randomly 20 quadrates and count the number of species present in a woodland or grassland. What’s on our doorstep ?

38. B3.13 a Look at the photograph and information and answer all the questions: When scientists want to count and identify different plant and animals species in a habitat, they commonly use a line transect and sample every metre for 25 metres what is present inside a quadrant measuring 25cm by 25 cm. This methods given not a total count but a sample of what's living in a particular habitat. It would be very time consuming to count every individual plant and animal along the transect line ! Why is sampling not as accurate as counting everything you find along the transect line ? Look at the picture below left, describe how the distribution of species change from the shore line (left) to the stable dune (right) ? Explain why black oak is only found in older and more stable habitats away form the shore line ? Colonisation of a dune habitat Key concepts

39. B3.13 b Look at the photograph and information and answer all the questions: Even bare rock is colonised by both plant and nails species over time. This is called colonisation. First the mosses and the lichens begin to grow and create small pocks of soil. Then the smaller shrubs and plants become established. These plants will also begin to attract invertebrate species. Finally the vertebrates, and the trees begin to colonise and dominate the land. Explain how lichens and mosses first succeed in colonising bare rock Why do the invertebrates begin to colonise after the appearance of small plants and shrubs ? If you cam back after another 50 years what might have changed over that time period ? Colonisation of bare rock colonisation maturing habitats new habitat lichens and mosses shrubs invertebrates trees vertebrates Key concepts

40. B3.13 Plenary Lesson summary: record organisms sampling count Friday 21 October 2011 50 random selected hedge sites were surveyed. The following were considered and reordered: the average maximum height, the average width, evidence of hedge cutting, percentage cover of different plants, the number of fruits present in autumn, percentage area showing gaps and the use of land next to the hedge. The survey also included comparing sites with each other. The variety of different plants species in a hedge tells the probable age of the hedge. How Science Works: Revise and prepare for end of module test Preparing for the next lesson: Scientists need to be able to _______ and _________ both plant and animal species in any habitat. Scientist measure and _______ the species found in a particular habitat. This helps them understand the ways in which different ________ depend on each other. Decide whether the following statements are true or false : False True 3: Long term monitoring is needed to decide if a species is endangered ? False True 2: Random selection means that the site is chosen without organised method ? False True 1: A line transect is usually 1000 metres long ?