Presentation on theme: "17/04/2015 AQA Biology Unit 1 W Richards This PowerPoint supports sections B1.4, B1.5, B1.6, B1.7 and B1.8 of the 2011 AQA Biology Unit 1 module."— Presentation transcript:
17/04/2015 AQA Biology Unit 1 W Richards This PowerPoint supports sections B1.4, B1.5, B1.6, B1.7 and B1.8 of the 2011 AQA Biology Unit 1 module
17/04/2015Adaptation Organisms are ADAPTED to the habitat they live in. In other words, they have special features that help them to survive. Some examples:
Extreme environments Deep sea volcanic vents Mountains The Arctic
17/04/2015Competition Any living species competes with each other. They may compete for: - Living space - Food - Water In addition to this competition, the population of a species can be affected by predators, disease, migration etc Get off my land Yum!
17/04/2015 Extinct Species Dodo Sabre-toothed tigers and mammoths What factors have caused these species to become extinct?
17/04/2015 Endangered Species What factors have caused these species to become endangered?
17/04/2015 Pollution Indicators Lichens in very clean air Lichens in clean air Lichens in slightly dirty air Lichens can be used as air pollution indicators:
17/04/2015 Pollution Indicators In dirty water leeches and midges will survive In average water more species (like the dragonfly and cranefly) will survive In clean water a lot more species (like the mayfly and caddisfly) will survive The quality of water can be monitored by looking at the species of insect in the water:
17/04/2015Biomass Plants use glucose from photosynthesis to produce starch and cellulose. This plant material is called “ biomass ” :
17/04/2015 Food chains A food chain shows where the biomass or energy goes in a food chain (in other words, “ what gets eaten by what ” ): Cabbage Rabbit Stoat Fox The arrows indicate where the energy is going Plants convert the sun ’ s energy into food through photosynthesis
17/04/2015 Pyramids of biomass In this food chain we can see that the mass of organisms in each stage is less than in the previous stage: CabbageRabbitStoatFox We can draw a “ Pyramid of Biomass ” to show this pattern: Mass of cabbages Mass of rabbits Mass of stoats Mass of foxes
17/04/2015 Energy flow in a food chain Consider the energy flow in this food chain: CabbageRabbitStoatFox 100%10%1%0.1% 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: 1)Each organism has to ____, keep warm etc 2)Energy is lost through faeces (______) Words – 10%, move, sun, waste, cabbage
17/04/2015 Recycling ourselves 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. Eating Waste Death Broken down Absorption
17/04/2015 The Carbon Cycle CO 2 in air 1. CO 2 is taken in by plants and algae for photosynthesis and turned into carbohydrates, fats and proteins 2. Plants and algae release CO 2 through respiration 3. The carbon taken in by plants is then eaten by animals and the animals that eat them 5. Animals (and plants) die and their remains are fed on by microbes and detritus feeders 6. These microbes also release CO 2 through respiration 4. Animals release CO 2 through respiration Burning fossil fuels also releases CO 2
17/04/2015Variation “ 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: 1)Ways in which they are the same: 2)Ways in which they are different:
17/04/2015 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.
17/04/2015 Genes, Chromosomes and DNA
17/04/2015 An example - Boy or Girl? XY X XXXY GirlBoy
17/04/2015 Father Mother Son Daughter Boy or Girl?
17/04/2015 Sexual vs. Asexual reproduction 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 ” ) “Snuppy” – the first cloned dog (Aug 05)
17/04/2015 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
17/04/2015 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
17/04/2015 Cloning Animals Method 1 – “Embryo transplants” A developing embryo is “split” before the cells specialise and the identical embryos are implanted into host mothers.
17/04/2015 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.
17/04/2015 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.
17/04/2015 Genetic Engineering YesNo Should genetic engineering be allowed?
17/04/2015Evolution Charles Darwin ( ) 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.
17/04/2015 The “Evolution Tree” Family Hominidae (Great Apes) Family Hylobatidae (Lesser Apes) Subfamily Hominidae Subfamily Ponginae Tribe HominiTribe Panini Tribe Gorillini HumansChimpanzeesGorillasOrangutansGibbons
17/04/2015 Evidence for Evolution The Grand Canyon Fossil records “Missing links” Humans with tails
17/04/2015Evolution 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:
17/04/2015 Natural Selection 1) Each species shows variation: 2)There is competition within each species for food, living space, water, mates etc 4)These survivors will pass on their better genes to their offspring who will also show this beneficial variation. Get off my land Gutted! Yum 3)The “ better adapted ” members of these species are more likely to survive – “ Survival of the Fittest ”
17/04/2015 An example – the peppered moth
17/04/2015 Darwin vs Lamarck 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: Jean Baptiste Lamarck ( 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.
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