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AQA Biology Unit 1

AQA Biology Unit 1. This PowerPoint supports sections B1.4, B1.5, B1.6, B1.7 and B1.8 of the 2011 AQA Biology Unit 1 module. W Richards. Adaptation. Organisms are ADAPTED to the habitat they live in. In other words, they have special features that help them to survive. Some examples:.

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AQA Biology Unit 1

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  1. AQA Biology Unit 1 This PowerPoint supports sections B1.4, B1.5, B1.6, B1.7 and B1.8 of the 2011 AQA Biology Unit 1 module W Richards

  2. Adaptation Organisms are ADAPTED to the habitat they live in. In other words, they have special features that help them to survive. Some examples:

  3. Extreme environments Mountains The Arctic Deep sea volcanic vents

  4. Competition Any living species competes with each other. They may compete for: Get off my land - Living space - Food - Water In addition to this competition, the population of a species can be affected by predators, disease, migration etc Yum!

  5. Extinct Species Sabre-toothed tigers and mammoths Dodo What factors have caused these species to become extinct?

  6. Endangered Species What factors have caused these species to become endangered?

  7. Pollution Indicators Lichens in clean air Lichens in very clean air Lichens in slightly dirty air Lichens can be used as air pollution indicators:

  8. Pollution Indicators In clean water a lot more species (like the mayfly and caddisfly) will survive In dirty water leeches and midges will survive In average water more species (like the dragonfly and cranefly) will survive The quality of water can be monitored by looking at the species of insect in the water:

  9. Measuring Environmental Changes Recording temperature changes Measuring rainfall Recording oxygen levels

  10. Biomass Plants use glucose from photosynthesis to produce starch and cellulose. This plant material is called “biomass”:

  11. Food chains Cabbage Rabbit Stoat Fox Plants convert the sun’s energy into food through photosynthesis The arrows indicate where the energy is going A food chain shows where the biomass or energy goes in a food chain (in other words, “what gets eaten by what”):

  12. Pyramids of biomass Cabbage Rabbit Stoat Fox Mass of foxes Mass of stoats Mass of rabbits Mass of cabbages In this food chain we can see that the mass of organisms in each stage is less than in the previous stage: We can draw a “Pyramid of Biomass” to show this pattern:

  13. Energy flow in a food chain Cabbage Rabbit Stoat Fox Clearly, not all of the ___’s energy that becomes stored in the _______ will end up in the fox. Only around ______ is passed on to the next stage in each food chain. • Energy is lost to the surroundings at each stage because of a number of reasons: • Each organism has to ____, keep warm etc • Energy is lost through faeces (______) Consider the energy flow in this food chain: 100% 10% 1% 0.1% Words – 10%, move, sun, waste, cabbage

  14. Recycling ourselves Eating Waste Death Absorption Broken down Microbes are the key to this – they break down waste and dead bodies so that the products can be used by plants for growth. Microbes work best in warm, moist conditions where there is plenty of oxygen.

  15. The Carbon Cycle Burning fossil fuels also releases CO2 CO2 in air 2. Plants and algae release CO2 through respiration 1. CO2 is taken in by plants and algae for photosynthesis and turned into carbohydrates, fats and proteins 6. These microbes also release CO2 through respiration 4. Animals release CO2 through respiration 5. Animals (and plants) die and their remains are fed on by microbes and detritus feeders 3. The carbon taken in by plants is then eaten by animals and the animals that eat them

  16. Variation “Variation” is the name given to differences between individuals of the SAME species. Variation is due to GENETIC or ENVIRONMENTAL causes. For example, consider dogs: • Ways in which they are the same: • Ways in which they are different:

  17. Sexual Reproduction The human egg and sperm cell contain 23 chromosomes each. When fertilisation happens the egg and sperm fuse together to make a single cell. This cell has 46 chromosomes (23 pairs) and continues to grow.

  18. Genes, Chromosomes and DNA

  19. An example - Boy or Girl? X Y X XX XY Girl Boy

  20. Boy or Girl? Daughter Mother Son Father

  21. Sexual vs. Asexual reproduction “Snuppy” – the first cloned dog (Aug 05) • Sexual reproduction: • 2 parents are needed • Offspring will have “pairs” of chromosomes • This will cause genetic variation • Asexual reproduction: • Only 1 parent needed • Offspring are GENETICALLY IDENTICAL to parent (“clones”)

  22. Cloning Plants Plants can reproduce ASEXUALLY. The offspring are genetically ________ to the parent plant and are called _________. Two examples: 1) This spider plant has grown a rooting side branch (“stolon”) which will eventually become __________. 2) A gardener has taken cuttings of this plant (which probably has good characteristics) and is growing them in a ____ atmosphere until the ____ develop. Words – clones, damp, independent, roots, identical

  23. Cloning Plants by tissue culture 1) Scrape off a few cells from the desired plant 2) Place the scrapings in hormones and nutrients 3) 2 weeks later you should have lots of genetically identical plants

  24. Cloning Animals Method 1 – “Embryo transplants” A developing embryo is “split” before the cells specialise and the identical embryos are implanted into host mothers.

  25. Cloning Animals Host mother Clone Method 2 - Fusion

  26. Uses of Genetic Engineering • With genetic engineering I can produce milk that contains: • Extra protein • Lower levels of cholesterol • Human antibodies Genetic engineering can also be used to grow bigger crop yields and to develop plants that are resistant to pesticides and herbicides.

  27. Genetic engineering - Insulin Step 1: Using enzymes “cut out” the part of the human chromosome that is responsible for producing insulin. Step 2: Using another enzyme cut open a ring of bacterial DNA. Other enzymes are then used to insert the piece of human DNA into it. Step 3: Place it into a bacterium which will start to divide rapidly. As it divides it will replicate and make millions of them, each with the instruction to produce insulin. Commercial quantities of insulin can then be produced.

  28. Genetic Engineering Yes No Should genetic engineering be allowed?

  29. Evolution Evolution is the theory of slow, continual change of organisms over a very long time. All living things on the Earth have supposedly developed from the first simple life forms that arrived 3,000,000,000 years ago. Charles Darwin (1809-1882)

  30. The “Evolution Tree” Family Hylobatidae (Lesser Apes) Family Hominidae (Great Apes) Subfamily Ponginae Subfamily Hominidae Tribe Panini Tribe Homini Tribe Gorillini Gibbons Orangutans Chimpanzees Gorillas Humans

  31. Evidence for Evolution The Grand Canyon Humans with tails Fossil records “Missing links”

  32. Evolution • The main evidence for my theory came from fossil records. However, these records didn’t exist when I came up with my theory. Also, there was little evidence about how species evolved so few people believed my ideas. • These days scientists understand that the process that causes evolution is called “Natural selection” and it works like this:

  33. Natural Selection 1) Each species shows variation: • There is competition within each species for food, living space, water, mates etc Get off my land • The “better adapted” members of these species are more likely to survive – “Survival of the Fittest” Gutted! Yum • These survivors will pass on their better genes to their offspring who will also show this beneficial variation.

  34. An example – the peppered moth

  35. Darwin vs Lamarck Jean Baptiste Lamarck (1744 - 1829 Darwin wasn’t the first to come up with evolution – he was simply the one credited with explaining how it worked (i.e. Natural Selection). An earlier scientist called Lamarck explained evolution by different means: The giraffe has a long neck because it “stretches” its neck to reach the food, and these long necks are passed on to their offspring. Organs which aren’t used will eventually disappear.

  36. This slideshow has been made freely available on the TES Resources website. More Science PowerPoints like this can be found at the website www.educationusingpowerpoint.com. This site contains slideshows that cover the 2011 AQA, EdExcel, OCR Gateway and OCR 21st Century courses (with more material being added every year) and A Level Physics and KS3 material. Some slideshows are free, others require a small subscription fee to be taken out (currently only £50 for a year). Further details can be found at Education Using PowerPoint.

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