8 Competition11/04/2017Any living species competes with each other. They may compete for:Get off my land- Living space- Food- WaterIn addition to this competition, the population of a species can be affected by predators, disease, migration etcYum!
9 Sabre-toothed tigers and mammoths Extinct Species11/04/2017Sabre-toothed tigers and mammothsWhat factors have caused these species to become extinct?Dodo
10 Endangered Species11/04/2017What factors have caused these species to become endangered?
11 Pollution Indicators Lichens can be used as air pollution indicators: 11/04/2017Lichens in very clean airLichens can be used as air pollution indicators:Lichens in clean airLichens in slightly dirty air
12 Pollution Indicators11/04/2017In dirty water leeches and midges will surviveThe quality of water can be monitored by looking at the species of insect in the water:In average water more species (like the dragonfly and cranefly) will surviveIn clean water a lot more species (like the mayfly and caddisfly) will survive
13 Measuring Environmental Changes 11/04/2017Recording temperature changesRecording oxygen levelsMeasuring rainfall
14 Biomass11/04/2017Plants use glucose from photosynthesis to produce starch and cellulose. This plant material is called “biomass”:
15 Food chains11/04/2017A food chain shows where the biomass or energy goes in a food chain (in other words, “what gets eaten by what”):RabbitCabbageFoxStoatThe arrows indicate where the energy is goingPlants convert the sun’s energy into food through photosynthesis
16 Pyramids of biomass11/04/2017In this food chain we can see that the mass of organisms in each stage is less than in the previous stage:CabbageRabbitStoatFoxWe can draw a “Pyramid of Biomass” to show this pattern:Mass of foxesMass of stoatsMass of rabbitsMass of cabbages
17 Energy flow in a food chain 11/04/2017Consider the energy flow in this food chain:100%10%1%0.1%CabbageRabbitStoatFoxClearly, 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 etcEnergy is lost through faeces (______)Words – 10%, move, sun, waste, cabbage
18 Recycling ourselves Eating Waste Death Absorption Broken down 11/04/2017EatingWasteDeathAbsorptionBroken downMicrobes 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.
19 The Carbon Cycle CO2 in air 11/04/20172. Plants and algae release CO2 through respirationBurning fossil fuels also releases CO2CO2 in air1. CO2 is taken in by plants and algae for photosynthesis and turned into carbohydrates, fats and proteins6. These microbes also release CO2 through respiration4. Animals release CO2 through respiration5. Animals (and plants) die and their remains are fed on by microbes and detritus feeders3. The carbon taken in by plants is then eaten by animals and the animals that eat them
20 Variation11/04/2017“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:
21 Sexual Reproduction11/04/2017The 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.
25 Sexual vs. Asexual reproduction 11/04/2017Sexual reproduction:2 parents are neededOffspring will have “pairs” of chromosomesThis will cause genetic variationAsexual reproduction:Only 1 parent neededOffspring are GENETICALLY IDENTICAL to parent (“clones”)“Snuppy” – the first cloned dog (Aug 05)
26 Words – clones, damp, independent, roots, identical Cloning Plants11/04/2017Plants 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
27 Cloning Plants by tissue culture 11/04/20171) Scrape off a few cells from the desired plant2) Place the scrapings in hormones and nutrients3) 2 weeks later you should have lots of genetically identical plants
28 Cloning Animals Method 1 – “Embryo transplants” 11/04/2017Method 1 – “Embryo transplants”A developing embryo is “split” before the cells specialise and the identical embryos are implanted into host mothers.
30 Uses of Genetic Engineering 11/04/2017With genetic engineering I can produce milk that contains:Extra proteinLower levels of cholesterolHuman antibodiesGenetic engineering can also be used to grow bigger crop yields and to develop plants that are resistant to pesticides and herbicides.
31 Genetic engineering - Insulin 11/04/2017Step 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.
32 Should genetic engineering 11/04/2017YesNoShould genetic engineeringbe allowed?
33 Evolution11/04/2017Evolution 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 ( )
34 The “Evolution Tree” Family Hylobatidae (Lesser Apes) 11/04/2017Family Hylobatidae (Lesser Apes)Family Hominidae (Great Apes)Subfamily PonginaeSubfamily HominidaeTribe PaniniTribe HominiTribe GorilliniGibbonsOrangutansChimpanzeesGorillasHumans
35 Evidence for Evolution 11/04/2017The Grand CanyonFossil recordsHumans with tails“Missing links”
36 Evolution11/04/2017The 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:
37 Natural Selection 1) Each species shows variation: 11/04/20171) Each species shows variation:There is competition within each species for food, living space, water, mates etcGet off my landThe “better adapted” members of these species are more likely to survive – “Survival of the Fittest”Gutted!YumThese survivors will pass on their better genes to their offspring who will also show this beneficial variation.
38 An example – the peppered moth 11/04/2017An example – the peppered moth
39 Jean Baptiste Lamarck (1744 - 1829 Darwin vs Lamarck11/04/2017Darwin 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.
40 This slideshow has been made freely available on the TES Resources website. More Science PowerPoints like this can be found at the website 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.