B1b

-Animals in cold climates are adapted to reduce the heat they lose from their bodies as much as possible

-Many Arctic mammals keep their surface area:volumer ratio as small as possiblr to help them hold onto their body heat 

-Their surface area of the skinned areas of their bodies is usually very small to reduce heat loss e.g their ears 

-Have plenty of insulations both inside and out. Blubber, a thick layer of fat that builds up under the skin, and a thick fur coat on the outside will help insulate them and reduce heat loss through skin 

-The fat layer also provides a food supply, animals often build up their blubber in the summer which they can live off through the winter when there is almost no food 

-They also use camouflage either so their prey can't see them coming, or so they can't be seen

-Many artic animals exchange the grey and browns of their summer coats for pure white in winter

-The biggest challenges if you live in a desert are;

• coping with the lack of water and,
• stopping your body temperature from getting too high 

-Many desert animals get their water they need from the food they eat 

-Most mammals sweat to keep themselves cool,but that means they also lose water

-Other ways they try to cool down are; most are often active in the early morning and late evening when it's not as hot

-Many desert animals are quite small,so their surface area is large compared to their volume, helping them to lose heat through their skin 

-They also don't have much fur and if they do it's fine and silk. They also have relatively little body fat stored under their skin 

-Large ears helps to increase heat loss 

-Plants need water for both photosynthesis and to keep their tissues upright

-They take in water through their roots into the soil, it moves up through the plant and is lost through the leaves in the transpiration stream

-There are small openings called stomata in the leaves of the lant which allow gases in and out for photosynthesis and respiratin, but water is also lost this way through evapouration 

- The rate at which a plant loses water is linked to the conditions its growing in. When it's hot and dry, photosynthesis and respiration take place quickly, to help prevent this they either reduce their surface area so they lose less water or store water in their tissues, or both

-A few desert plants have broad leaves with a large surface area, these leaves collect the dew that forms in the cold evenings, they then funnel the water towards their shallow roots

-Some plants in dry environments have curled leaves. This reduces the surface area of the leaf and also traps a layer of moist air around the leaf which cuts back the amount of water lost by evapouration 

-Most plants that live in dry conditions have reduced the surface area of their leaves, this cuts down the area from which water can be lost. Some desert plants have small fleshy leaves with a thick waxy cuticle to keep water loss down. The cuticle is a waxy covering on the leaf that stops water evapourating away 

-Desert plants such as a cacti have leaves that have been reduced to spines with a very small surface area to stop the cactus losing a lot of water, it also helps put animals off eating it as well 

-Plants cope with dry conditions by storing water in their tissues

-Plants which store water in their fleshy leaves,stems or roots are known as succulents 

-One of the biggest problems for plants is being eaten by animals 

-Plants adapted to prevent this by things such as; 

• thorns 
• unpleasant taste 
• poisonous chemicals 

Animals compete for;

• water 
• food
• territory
• mates 

-Competiton is common among carnivores, they compete for prey, the animals which are best adapted will be the most successful 

-Successful predators are adapted to have long legs for running fast and sharp eyes to spot prey, these features will be passed on to their offspring 

Plants compete for;

• space
• sunligt
• water
• nutrients 

-They need light for photosynthesis, to make food using energy from the sunlight. They need water for photosynthesis and to keep their tissues rigid and supported. Plants need minerals (nutrients) so they can make all the chemicals they need in their cells

-Small plants found in woodlands often grow and flower early in the year, because plenty of light gets through the bare branches of the trees.The leaves shed the previous autumn have rotted down to provide minerals in the soil 

-Some plants have shallow roots taking water and minerals from near the surface of the soil, others have long,deep roots which go far underground 

-To compete successfully, a plant has to avoid competition with its own seedlings. The most important adaptation for success is the way they spread their seeds 

-Many plants use the wind to help them, some seeds are so small they are carried easily by air currents. Others produce fruits with special adaptations for flight to carry their seeds as far away as possible

-Some plants use mini-explosions to spread their seeds, the pods dry out,twist and pop, flinging the seeds away 

-Juice berries, fruits and nuts are produced by plants to encourage animals to eat them. Once the animals has eaten them they are desposited with the waster material in their own little pile of fertiliser

-Fruits which are sticky or covered in hooks get caught up in the fur or feathers of passing animals, which are carried around until they fall off 

-Characteristics like nose shape,eye colour and dimples are inherited (passed on from your parents)

-Your ressemblance to your parents is the result of genetic information passed on to you in the sex cells (gametes) from which you develop

-The genetic information which is passed from generation to generation during reproduction is carried in the nucleus of your cells

-The nucleus contains the plans for making and organising a new cell

-Inside the nucleus of all your cells there are thread-like structures called chromosomes, which are made up of a special chemical called DNA where the genetic information is actually stored

-DNA is a long molecule made up of two strands which are twisted together to make a spiral, this is known as a double helix (A-T, G-C)

-Each different type of organism has a different number of chromosomes, humans have 46 chromosomes (23 pairs), you inherite half from your mom and half from your dad

-Each gene is a small section of the DNA, each gene is a different characteristic 

-Your chromosomes are arranged so that both of the chromosomes in a pair carry genes controlling the same things in the same place 

-Two different types of reproduction; sexual and asexual 

ASEXUAL REPRODUCTION;

-Only involves one parent, the process produces more organisms completely identical to itself, there is no joining of special sex cells and no variety in the offspring 

-Asexual reproduction gives rise to offsrping known as clones. Their genetic material is identical both to the parent and to each other. Although there is no variety, asexual reproduction is safe

SEXUAL REPRODUCTION;

-Involves the joining of a male sex cell and a female sex cell

-The result of sexual reproduction is that you inherit genetic information from both parents 

-In plants the gametes that are invloved are found within ouvules and pollen

-It's more risky because it relies on the two sex cells from two individuals meeting

-Two different types of reproduction; sexual and asexual 

ASEXUAL REPRODUCTION;

-Only involves one parent, the process produces more organisms completely identical to itself, there is no joining of special sex cells and no variety in the offspring 

-Asexual reproduction gives rise to offsrping known as clones. Their genetic material is identical both to the parent and to each other. Although there is no variety, asexual reproduction is safe

SEXUAL REPRODUCTION;

-Involves the joining of a male sex cell and a female sex cell

-The result of sexual reproduction is that you inherit genetic information from both parents 

-In plants the gametes that are invloved are found within ouvules and pollen

-It's more risky because it relies on the two sex cells from two individuals meeting

-Sexual reproduction shows more variation, which is a great advantage in making sure the species survives. The more variety in a group of individuals,the more likely it is that at least a few of them will have the ability to survive difficult conditions 

-Alleles are different verisons of the same gene 

-A clone is an individual which has been produced asexually from its parents 

CLONING PLANTS;

-Producing new plants by taking cuttings from older plants is a form of artificial asexual reproduction 

-To take a cutting you remove a small piece of a plant, and if you grow it in the right conditions, new roots and shoots will form to give you a small,complete new plant 

-It's quick and cheap and the cutting will be genetically identical to the parent plants 

-Many growers use hormone rooting powder to encourage cuttings to grow 

-More expensive

-Allows you to make thousands of new plants from a tiny piece of plant tissue 

-If you use the right mixture of plant hormones,you can maek a small group of cells from the plant to produce a big mass of identical plant cells 

-This type of cloning guarantees that the plants you grow will have the characteristics you want 

-Common in farming 

-In embryo cloning, you give a top-quality cow fertility hormones to make her produce a lot of eggs

-Fertilise eggs using sperm from good bull, often done inside cow

-Embryos produced are gently washed out of womb, sometimes eggs are collected and sperm added in lab to produce the embryos 

-At this early stage of development every cell of the embryo can still form all of the cells needed for a new cow, they haven't become specialised 

1)Divide each embryo into several cells

2) Each cell grows into an identical embryo in lab 

3) transfer embryos to host mother

4) Identical clone calves born

FUSION CELL CLONING;

-nucleus taken from adult cell, at same time nucleus is removed from egg cell from another animal of same species, nucleus from original adult cell is placed in empty egg cell and the new cell is given a tiny electric shock, fuses new cell together, and starts process of cell division,and embryo begins to develop which is genetically identical to the original adult animal 

-Adult cell/reproductive cloning is when a new animal is produced 

ADVANTAGES;

-Animals which have been geneticallly engineered to produce useful proteins in their milk can be cloned

-Help save animals from extinction 

DISADVANTAGES;

-Fear of leading to clones of babies, reduces variety

-Genetic engineering/genetic modification is used to change an orgainism and give it new characteristics we want to see

-It involves changing the genetic material of an organism, you take a small piece of DNA/a gene from one organism and transfer it to the genetic material of a completely different organism

-So, for example, the genes can be 'cut out' using enzymes and transferred to the cell of a bacterium. Your gene carries on amking human protein,even though it's now a bacterium 

-If genetically engineered bacteria are cultured on a large scale they will make huge quantities of protein from other organsims

-Can make exactly the protein needed, in the exact amounts, and in a very pure form 

-Improves growth rate of plants and animals 

-Used to improve the food value of crops and reduce fat levels in meat

-Used to produce plants which make their own pesticide chemicals

-GM food lasts longer, designed to grow well in all weather, could solve world hunger 

-Number of sheep and other mammals have been engineered to produce life-saving human proteins in their milk, these are much more complex proteins than the ones produced by bacteria 

-No-one can be sure of the long term effects 

-Concerns on GM food on healtth 

-GM crops are often made infertile, which means farmers in poor countries are going to have to buy new seeds every year 

-People might want to manipulate the genes of their future children (designer babies)

-Scientists think that during the Earth's history, 4 billion species have lived 

-Fossil records can give us an insight into how much or little organisms have changed

-Fossil records are not complete because so much rock has been broken down,worn away,buried or melted over the years 

-Fossil can be forme in a number of ways;

• Many fossils formed when harder parts of the animal or plant were replaced by other minerals over long periods of time, these are the most common fossils 
• Another type of fossil is formed when an animals or plants haven't decayed after it dies. Sometimes the temperature was too low for decay to take placeand the animals and plants were preserved in ice, these fossils are rare 
• Some of the fossils we find are not of actual animals or plants, but rather traces like footprints 

-Hyracotherium from 55 million years ago, 0.4m, small,swamp-dwelling with well spread out toes for walking on soft ground 

-Mesohippus from 37 million years ago,0.6m,bigger only three toes on ground for moving faster on drier ground

-Merychippus from 25 million years ago, 1.0m, bigger again,walking mainly on one enlarged toe for speed

-Pliohippus from 5 million years ago, 1.0m, single foot forming hoof, looks more like modern horse 

-Modern horse (Equus) from 2 million years ago, 1.6m, fast runner on hard ground with one toe forming the hoof

-The theroy of evolution tells us that all the species of living things alive today have evolved from the first simple life forms that existed on Earth 

-LAMARCK'S THEROY OF EVOLUTION;

-French biologist, suggested that all organisms were linked by what he called a 'foundation of life'

-His idea was that every type of animal evolved from promitive worms. He thought that the change from worms to other organisms was caused by the inheritanc of acquired characteristics 

-The theroy was that useful changes, developed by parents during their lives to help them survive, are passed on to their offspring

-His theroy fell down for many reasons;

• there was no evidence for the 'foundation of life'
• people didn't like the idea of being descended from worms
• people didn't think their characteristics were passed on to their children-they couldn't see it 

-Set out in 1831 as the ship's naturalist on HMS Beagle

-He was 22, and the voyage to South America and the South Sea Islands would take 5 years

-Planned to study geology on the trip

-In South America he discovered a new form of the common rhea, an ostrich like bird

-On the Galapagos Island he was amazed by the variety of species and the way they differed from island to island

-Found strong similarities between types of finches,iguanas and tortoises on the different islands

-Each was adapted to the comditions 

-he collected large numbers of specimens of animals and plants during explorations

-He made detail drawings and kept written observations 

-Built up evidence from breeding experiments 

-Publishes book On the Origin of Species by means of Natural Selection in 1859

-All living organisms have evolved from simpler life froms

-This evoluation has come about by a process of natural selection

-Reproduction always gives more offspring than the environment can support

-Only those which are most suited to their environment, the 'fittest' will survive

-When they breed, they pass on those useful characteristics to their offspring 

The part played by mutation;

-New forms of genes (new alleles) result from changes in existing genes, these changes are known as mutations, there are tiny changes in the long strands of DNA

-Mutations occur naturally through mistakes made in copying your DNA when cells divide

-Mutations introduce more variety into the genes of a species 

-Many mutations have no effect on the characteristics of an organism,and some mutations are harmful 

-A mutation produces an adaptation which makes an organism better suited to its environment which makes it more likely to survive and breed 

-Extinction is the permanent loss of all the members of a species form the face of the Earth 

-As conditions change, new species evolve which are more suited to survive the new conditions

-At the same time older species which cannot cope with the changes,gradually die out

-Changes in the climate or environment are the main causes of extinction 

-The other main cause of extinction is other living things;

• If a new predator is in the area, it can wipe out unsuspecting prey very quickly because the prey don't have the adaptations to avoid it 
• New disease, can drive species to extinction, they are most likely to cause extinction on islands where populations live closer together 
• Competition, mutations can give oragnisms advantages, if the new species is successful it may take over from the original animal 

-When fossil fuels are burned, carbon dioxide is released into the atmosphere as a waste product

-Fossil fuels also contain sulfur impurities, when these burn they react with oxygen to form sulfur dioxide gas

-At high temperatures, nitrogen oxides are also released into the atmosphere

-These gases pollute the air and can cause serious breathing problems for people if the concentration gets too high

-The sulfur dioxide and nitrogen oxides dissolve in the rain and react with oxygen in the air to form dilute sulfuric acid and nitric acid, making the rain more acidic (acid rain)

-Can kill leaves

-Soals into the soil and destroys roots of trees

-Falls into lake,rivers and streams turning them acidic

-The sulfur and nitrogen oxides are carried high in the air by prevailing winds

-As a result, it is often relatively 'clean' countries which get the pollution and acid rain 

-Catalytic converters are fitted into some cars to remove the acidic gases before they are released into the air 

-Carbon dioxide and methane are building up in the  atmosphere and acting like a greenhouse around the Earth

-The greenhouse gases absorb much of the energy which is radiated away, it can't escape into space and as a result the Earth and its surrounding are warmer then they should be 

-If the Earth's temperature increases,ice caps will melt causing sea levels to rise, meaning more flooding 

-Methane levels are rising,it has two major sources;

• As rice grows in swampy conditions known as paddy fields,methane is released. As the population of the world has grown so has the farming of rice
• Cows produce methane during their digestive processes amd release it at regualr intervals. In recent years the number of cattle jas increased to produced cheap meat for fast foods

-Can use linchens as  air pollution indicators

-Can use invertabrate animals as water pollution indicators

-Green field sites are places that haven't been built on before

-Brown field sites have, often sites of old buildings, factories, petrol stations or rubbish tips

-Advantages of using brown field sites; water,sewage,electricity,gas,and transport systems are usually already in place or easily available. No countryside or farmland is lost or spoilt 

-Brown field sites are often contaminated with chemicals and can suffer from subsidence, because of this they are often expensive (have to be cleaned up/decontaminated)