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Kingdom (Animalia, Plantae, Fungi, Prokaryotae (bacteria), Protoctista) Phylum Class Order Family – always ends ‘ae’ or ‘ea’ Genus – Italicised, capital letter Species – Italicised, lower case letter, Linnaeus Classification Kingdom Phylum Class Order Family Genus species Mnemonic Largest Smallest Knowledge Plus Careful Observation Frequently Guarantees success Vertebrates = having a backbone or spinal column. (eg cat, human, fish, frog) phylum chordata. Invertebrates = Lacking a backbone or spinal column. (eg slug, starfish, insects) Name Main characteristics Fish Have wet scales and gills, lay eggs in water. Amphibians Have smooth, moist, permeable skin. Adults have lungs. They lay eggs in water. Reptiles Have dry, scaly skin. Have lungs They lay leathery shelled eggs. Mammals Have hair on their body and mammary glands that produce milk. Have lungs. They give birth to live young. Birds Have feathers and a beak. Have lungs. They lay hard shelled eggs. Absorbing oxygen? Fish and young amphibians = gills Mammals, birds, reptiles and adult amphibians = lungs Reproduction? Internal fertilisation – sperm meets egg inside the body = mammals External fertilisation – female lays eggs then male releases sperm onto them = fish, amphibians Maintaining Body temperature? Homeotherms – keep body temperature constant by releasing heat to their surroundings = mammals Poikilotherms – body temperature changes with surroundings = reptiles Species are organisms that are capable of interbreeding to produce fertile offspring. Have Binomial Names eg Homo sapiens Felis catus Exceptions 1. Hybrids (cross between 2 different species) eg horse and donkey = mule 2. Ring Species Sometimes there are a chain of neighbours that can all breed with their neighbour but the ones at either end can’t. These are called a ring species. Differences within a species. – Caused by the environment eg. hair Environmental length, sun tan – inherited eg. natural hair colour, eye colour, certain diseases such as cystic fibrosis Genetic variation – range from low to high eg height, weight Continuous Discontinuous colour variation – distinct categories eg eye Height An allele is an alternative form of a gene (one member of a pair). Organisms have two alleles for each characteristic eg hair colour, eye colour. Gamete (egg) 23 chromosom es 23 chrom osom es 23 pairs of chromosomes (one from each gamete) Gamete (Sperm) Normal Body Cell Capital letters show dominant alleles Lower case letters show recessive alleles The letters in the boxes represent the genotype The characteristic you see is called the phenotype eg red flowers •The dominant allele for brown eyes is B. •The recessive allele for blue eyes is b. A mother with brown eyes and a genotype Bb reproduces with a father with brown eyes and genotype Bb. What chance does the next generation have of having: Brown eyes? Blue eyes? B b B BB (brown) Bb (Brown) b Bb (Brown) bb (blue) Ratio = 3 brown:1 blue Probability = 3 in 4 brown 1 in 4 blue Percentage chance = 75% brown 25% blue Inherited disease caused by 2 recessive alleles (cc). Dominant allele (C) causes person to be CC – healthy or Cc - carrier. Symptoms thick sticky mucus on lungs coughing bacterial chest infections Breathlessness What chance of having cystic fibrosis from two carrier (Cc) parents? 1a. Which people have the disease? b. What alleles do they have? Dominant – C Recessive - c 2. Al and Bev have the same alleles – what are they? Al Izzie 3a. Izzie could have 2 combinations of alleles – what could they be. b. Why can we not tell from this diagram which ones they are? Bev Jack Deb Fred Helen Gary Emma Inherited disease caused by two recessive alleles (ss). Healthy = SS Carrier = Ss Red blood cells become mis shaped so can’t carry as much oxygen. Symptoms Tiredness Shortness of breath Pale skin Fainting Homeostasis is maintaining a stable internal environment inside the body. Vasoconstriction When it is cold, capillaries under the skin contract (get narrower) to reduce blood flow to the skin. Vasodilation When it is warm, capillaries under the skin dilate (get wider) to increase flood flow near the skin. What is the sense? What stimulus is detected by the receptors? Skin Touch Pressure, pain, heat, cold Eye Sight Light Nose Smell Chemicals in air Ear Hearing Sound waves Tongue Taste Chemicals in food Sense Organ Brain Spinal Cord The main part is called the central nervous system (CNS). It consists of the brain and spinal cord. The nervous system carries electrical impulses to and from all parts of your body. Myelin Sheath Stimulus eg smelling food Impulse starts at r_________ (n____) Impulse passed along s_________ neurone Impulse travels to C________ N_________ S__________ Response – walk to food shop E_________ (muscle) receives impulse to react Impulse passed along m______ neurone Stimulus – stepping on a pin Impulse starts at r_________ Impulse passed along s_________ neurone Impulse passed along r______ neurone Response – lift foot away from pin E_________ receives impulse to react Impulse passed along m______ neurone Hormones are c__________ messengers. They are released by glands called e_________ glands that are found in organs. Hormones travel in the b______ p______. The organ affected by the hormone released is called the t_____ organ. This is not always the same as the organ that releases the hormone. Type 1 Type 2 Onset Usually born with Acquired in later life Problem? Pancreas produce insulin but cells don’t respond to it Cause Pancreas does not produce insulin Genetic Treatment Inject insulin •May need to inject insulin •May be able to have tablets •May control with low sugar diet and regular exercise. Obesity, high fat/sugar diet, lack of exercise, old age Plant Hormones Plant stems always grow towards the light. This is called positive phototropism. It is controlled by a hormone called auxin and sunlight. Plant roots always grow downwards. This is called positive geotropism. It is also controlled by the hormone auxin and gravity. Selective Weedkillers Auxin sprayed on crops. Makes broad leaf plants (like weeds) grow out of control and die. Doesn’t affect the crop. Fruit Ripening Hormones used to speed up ripening so fruit can be picked in one go, or to ripen fruit so it is ready to eat. Eg ethylene on bananas shipped in from abroad. Seedless Fruit Spray plants with hormones to make fruit grow but not the seeds. Rooting Powder Cut plant stems dipped into hormones to encourage roots to grow. Addictive - stimulate receptors in the brain. Need more and more to get the same effect. Dependent – need the drug to get by each day. Hallucinogens – distort perception of sight/soun/smell/taste eg magic mushrooms, LSD Narcotics – make you sleepy Stimulants – speed up nervous system eg caffeine, nicotine, cocaine Depressants – slow down nervous system eg alcohol, cannabis Tar – sticky, sticks to inside of lungs. Carcinogen (causes cancer) Nicotine – the drug that makes cigarettes addictive Carbon monoxide (CO) – binds with haemoglobin in red blood cells instead of oxygen. Reduces the amount of oxygen the blood can carry. Short term effects Slow down activity of brain and nervous system (depressant) Slows reaction times – blurred vision, slurring, possible unconsciousness/death Reduces inhibitions Long Term Effects Liver cirrhosis – irreversible damage can lead to liver failure/death Brain damage/blood clots in the brain Donor (may be dead/alive for certain organs eg 1 kidney) Provides organ for person with organ failure. Heart, lungs, kidney, liver, corneas, Whether to give or not (an ethical decision) Age? Obesity? Misuse of drugs? Close match? How ill is the recipient? Microorganisms (bacteria fungi and viruses) that cause disease. By damaging cells or releasing toxins. If the microorganism doesn’t make you ill it is not a pathogen eg penicillium mould on bread. A microorganism that can cause harm or disease is called a pathogen. Pathogen Not a pathogen Direct Contact Touching – athlete’s foot (fungus) Kissing – herpes virus Sexual contact – HIV (virus) Sneezing – Influenza (virus) Indirect Contact Vehicle Borne (physical things) o In water – Cholera (bacteria) o In food – Salmonella (bacteria) o On objects – Tetanus (bacteria) Vector Borne (via animals) ◦ Dog bite – rabies ◦ Anopheles Mosquito – malaria (protazoan) ◦ Housefly – Dysentary (bacteria) Chemical Barriers Physical Barriers Antiseptics – chemicals that have antibacterial properties. Often extracted from plants. • Toxins produced by fungi that kill bacteria. • Eg penicillin, amoxycillin, streptomycin Misuse: Not completing course Taking for viral infections LEADS TO BACTERIAL RESISTANCE Food Chains •Only shows one organism at each stage. •Start with a producer. •If the organism eats something it is a predator. •Things eaten by predators are called pray. •Changes in numbers of organisms in the chain will affect the whole food chain. Food webs •More than one predator may eat the same pray. •More than one type of pray may be eaten by the same predator. •What would happen to the numbers of rabbits if the number of snails decreased? Pyramid of biomass Pyramid of numbers Parasitism – two organisms live together with one feeding off the other. The organism the parasite feeds off is called the host. eg. headlice and fleas Mutualism – two organisms live together and both benefit eg tubeworms and bacteria, legumes (bean plants) and nitrogen fixing bacteria. Causes Population growth – more resources used fossil fuels – release CO2 and SO2 into air – fossil fuels – global warming Burning uses fertilisers – washi into lakes and rivers – causes EUTROPHICATION Farming Fertilisers (nitrate, phosphate, potassium) wash into rivers and streams. Cause rapid, excessive growth of algae. Algal bloom blocks light from underwater plants for photosynthesis so plants die. Decomposing bacteria decay plants and use OXYGEN for repiration. Lack of oxygen causes fish and other organisms to die. Organisms that are sensitive to pollution can be used to indicate the presence of pollution. Blackspot Fungus – killed by sulphur dioxide Lichens (fungus and algae mutualistic relationship) – certain species indicate high/low levels of sulphur dioxide and nitrogen oxides Stonefly Larvae and Freshwater shrimps need lots of O2 Bloodworms and Sludgeworms – little O2 The CARBON CYCLE involves four very important steps 1) 2) 3) 4) PHOTOSYNTHESIS RESPIRATION DECAY BURNING FOSSIL FUELS fixing bacteria – atmospheric nitrogen to nitrates Nitrogen Decomposing Bacteria - animal/plant matter to urea and ammonia Denitrifying Bacteria - ammonia to atmospheric nitrogen Animals eat plants and take in nitrogen compounds eg proteins