30/08/2015 Evolution and the Environment (AQA)

30/08/2015Adaptation 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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Long, deep roots. Large body. Leaves are spines/thick cuticle. Spines. Water collection. Store water. Reduce water loss. Prevent animals eating it.

30/08/2015Competition 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!

30/08/2015 Red squirrel. Grey squirrel.

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Red SquirrelGrey Squirrel FoodSeeds, buds, flowers, leaves and fruit. Seeds, nuts, buds, insects, bird eggs and fungi, depending on the time of year. HabitatWoodland that contains a fair proportion of conifer trees. Very adaptable. Prefers mature broadleaved woodlands. BreedingOne or two litters a year, usually of about 2-3 young. If conditions are good, two litters are produced each year, consisting of 1-8 young. Size g g. StatusNative.Introduced from USA In WalesA few places, e.g. Clocaenog Forest in North Wales (<100). Widespread.

30/08/2015 Predators and Prey A PREDATOR is an animal that hunts and eats another animal The PREY is the animal it eats, for example… Consider the populations of these two animals over time: Hey! I ordered a steak Population of animal Time Rabbit Fox Prey Predator

30/08/2015Variation “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:

30/08/2015 Where is this information stored? Section of a chromosome: Genes for eye colour Genes for hair colour Genes for blood group: Different species have different numbers of chromosomes. Humans have 46 (23 pairs) in every cell.

30/08/2015 Where is this information stored? Slide 43

30/08/2015Karyotype

Sexual Reproduction The human egg and sperm cell (“GAMETES”) contain 23 chromosomes each. When fertilisation happens the gametes fuse together to make a single cell called a ZYGOTE. The zygote has 46 chromosomes (23 pairs) and contains information from each parent. We have similar characteristics to our parents due to genetic information being passed down in genes through gametes:

30/08/2015 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)

30/08/2015 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

30/08/2015 Cloning Animals Method 1 – “Embryo transplants” A developing embryo is “split” before the cells specialise and the identical embryos are implanted into host mothers.

30/08/2015 Cloning Animals Method 2 - Fusion Host motherClone Mimi

30/08/2015 Selective breeding I raise cows. Each type of cow is good at a certain job. The Friesian cow produces large quantities of milk, the Jersey cow produces very nice milk and the Hereford cow produces lot of beef. If, for example, I want lots of milk I would only breed Friesian cows with each other – this is SELECTIVE BREEDING. Friesian Jersey Hereford

30/08/2015 Selective breeding vs. Cloning AdvantagesDisadvantages Cloning Selective breeding

30/08/2015 Selective breeding vs. Cloning AdvantagesDisadvantages Cloning 1)Allows large numbers of organisms with good characteristics to be produced 2)Very efficient 1)Causes reduced numbers of alleles 2)Loss of variation could harm survival chances if the environment changes Selective breeding 1)Produced organisms with favoured characteristics 2)Very efficient and economically viable 1)Causes reduced numbers of alleles 2)Loss of variation could harm survival chances if the environment changes

30/08/2015 Genetic Modification Possible uses of genetic modification of organisms: -Improving crop yield -Improving resistance to pesticides -Extend shelf-life -Manufacture a certain chemical (e.g. insulin) -Convenience

30/08/2015 Genetic engineering Insulin is a hormone produced by the pancreas to help control blood sugar levels. Diabetics can’t produce enough insulin and often need to inject it. Insulin can be made by genetic engineering:

30/08/2015 Genetic engineering - Insulin Step 1: Using RESTRICTION ENZYMES “cut out” the part of the human chromosome that is responsible for producing insulin. Step 2: Using another restriction enzyme cut open a ring of bacterial DNA (a “plasmid”). Other enzymes are then used to insert the piece of human DNA into the plasmid. Step 3: Place the plasmid into a bacterium which will start to divide rapidly. As it divides it will replicate the plasmid and make millions of them, each with the instruction to produce insulin. Commercial quantities of insulin can then be produced.

30/08/2015Evolution Charles Darwin ( )

30/08/2015Evolution Evolution is the slow, continual change of organisms over a very long time. All living things on the Earth have developed from the first simple life forms that arrived 3,000,000,000 years ago. One of the effects of evolution is that species will become better adapted to their environment. If these species don’t adapt they may become extinct due to being unable to deal with any of these factors… 1)Increased competition 2)Changes in the environment 3)New diseases 4)New predators

30/08/2015 The “Evolution Tree” Family Hominidae (Great Apes) Family Hylobatidae (Lesser Apes) Subfamily Hominidae Subfamily Ponginae Tribe HominiTribe Panini Tribe Gorillini HumansChimpanzeesGorillasOrangutansGibbons

30/08/2015 Evidence for Evolution The Grand Canyon Fossil records “Missing links” Humans with tails

30/08/2015Evolution My key observations: 1)All living things produce more offspring than survive to adulthood 2)In spite of this, population sizes remain roughly constant 3)Variation exists among species 4)Characteristics can be passed on from one generation to the next. These observations led me to the conclusion that species evolve over a along period of time by a mechanism called “Natural Selection”. The main evidence for this is from fossil records.

30/08/2015 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”

30/08/2015 A smaller example… Consider the four steps of natural selection in the example of some bacteria that has become resistant to penicillin: 1)Variation – some strains of bacteria are resistant and some aren’t. 2)Competition – The non-resistant bacteria are killed by the penicillin. 3)Survival of the fittest – the resistant bacteria survive. 4)Passing on of genes – the resistant bacteria reproduce and pass on their adaptations to their offspring. Bacteria Penicillin

30/08/2015 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.

30/08/2015 Population and Pollution The human population is growing exponentially: Population Time This has a number of effects on the environment: Bigger population means… Building – more buildings needed Farming – less land available for crops Waste – more waste needs to be disposed of Quarrying and mining – raw materials and sources of energy are being used up

30/08/2015Pollution Humans pollute the Earth in a number of ways: Water – with sewage, fertiliser or toxic chemicals Air – with smoke or gases such as sulphur dioxide Land – with toxic chemicals, pesticides and waste NO, NO 2 and CO Acid rain Power stations produce CO 2, SO 2 and NO 2 Cars produce NO, NO 2 and CO These gases produce acid rain (which affects tress and buildings) and worsens the greenhouse effect

30/08/2015 Pollution Indicators Lichens in very clean air Lichens in clean air Lichens in slightly dirty air Lichens can be used as air pollution indicators:

30/08/2015 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:

30/08/2015Deforestation

Deforestation Why it happensEffects

30/08/2015 The Greenhouse Effect We get heat from the sun: A lot of this heat is _______ back into space. However, most of it is kept inside the Earth by a layer of gases that prevent the heat escaping by _______ and then re-radiating it back again. This is called the _________ Effect. It has always been around, but is currently being made worse due to: 1)Burning (releasing CO 2 ) 2)__________ (removing trees that remove CO 2 ) 3)Increased micro organism activity (from rotting ______) 4)Cattle and rice fields (they both produce _______) These changes will cause GLOBAL WARMING and RISING SEA LEVELS Words – methane, radiated, absorbing, deforestation, waste, greenhouse

30/08/2015 Sustainable Development Sustainable development is all about preserving the world for tomorrow. There are three main strands: 1)Economic development 2)Social development 3)Environmental protection Examples of sustainable development include: 1)Replanting trees after chopping them down 2)Limiting the number of fish allowed in a catch 3)Protecting endangered species

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