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B7: Biology Across the Ecosystem Biology in Action A. Blackford.

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Presentation on theme: "B7: Biology Across the Ecosystem Biology in Action A. Blackford."— Presentation transcript:

1 B7: Biology Across the Ecosystem Biology in Action A. Blackford

2 Revision is important! WARNING This PowerPoint is not a substitute for active revision using notes, the workbook and revision guide. You also need to do plenty of past papers to get exam practice. Good luck!

3 Harvesting the sun Most of the energy used by living things ultimately came from the sun Plants harvest this energy by PHOTOSYNTHESIS. They are AUTOTROPHS Animals are HETEROTROPHS and need to eat ready made food.

4 Cycles in Nature Energy flows through the living system Nutrients (like CARBON and NITROGEN) are CYCLED in the system

5 Trapping Sunlight Energy What happens to the light energy that hits the leaf? 60% wrong wavelength 35% absorbed By chlorophyll 5% passes straight through 2% to new growth 33% lost as heat energy Leaves are green because RED and BLUE light is absorbed for use in photosynthesis and GREEN light passes through or is reflected.

6 Photosynthesis Light energy splits water into hydrogen and oxygen The reaction takes place in CHLOROPLASTS The Equation for Photosynthesis Carbon dioxide+Water Light energy +GlucoseOxygen Chlorophyll 6CO 2 6H 2 OC 6 H 12 O 6 6O 2

7 What is the glucose used for? Glucose is a carbohydrate It is the starting point for FATS, PROTEINS (with nitrates from the soil) other carbohydrates and CELLULOSE (for the cell wall) Changed into starch for storage (starch does not upset the OSMOTIC balance of the cell). For energy from respiration

8 GLUCOSE storage e.g. starch in potato starch fruits other sugars e.g. seed germination energy cytoplasm protein cell walls cellulose 18

9 The rate of Photosynthesis Changing the light intensity changes the rate of photosynthesis – up to a point! Light is limiting the rate of photosynthesis Light is NOT limiting the rate of photosynthesis (something else is) Increasing light intensity

10 Limiting factors (carbon dioxide) Light is limiting all the way along this line. Light is NOT limiting the rate here. Carbon dioxide IS. Increasing the CO2 concentration increases the final rate of photosynthesis

11 Compensation point Plants cells produce CO 2 all the time (from respiration) There are two compensation points each day At the compensation point the amount of carbon dioxide produced by respiration is equal to the amount of oxygen being produced by photosynthesis

12 The carbon cycle Vegetation

13 Feeding relationships Producers1 o Consumer2 o Consumer3 o Consumer ProducersHerbivoreCarnivore 1 st trophic level 2 nd trophic level 3 rd trophic level 4 th trophic level Oak treeInsectSparrowKestrel Increasing Size (usually) Decreasing Number (usually)

14 Pyramids of number or biomass? Counting the number of organisms along a food chain will usually give a pyramid of numbers (but not always)

15 Pyramid of biomass If the total mass of the organisms at different trophic levels are taken a pyramid of biomass is produced

16 Life underground Soil organisms are responsible for recycling nutrient such as nitrogen They are responsible for the decay of dead animals and plants Nematodes Soil microbes Bacteria Fungi Insects Flatworms Approx numbers per gram of soil

17 Living together 1 Commensalism One organism benefits but the other isnt harmed e.g. seeds sticking to the fur of animals for dispersal. Mutualism Both organisms in a relationship benefit e.g. clown fish are protected by anemone tentacles and they drop bits of food that the anemone feeds on (see your revision guide for more examples)

18 Living together 2 Parasitism Only one of the organisms benefit from this arrangement, the other is harmed by it. These are dust mites in a human eye lash follicle. They are 0.4 mm long. Most people have some. They LOVE makeup and will thrive if it is not taken off properly at night!

19 Human parasites These can get into the body by: Food or water Through nose, mouth, anus, genitial and urinary tracts Insect bites Burrowing under the skin

20 Tapeworms 1 Live in the human gut Can be very long (10m for fish tapeworm) Their head and suckers grip the gut wall They have a thick skin (cuticle) so they are not digested They can respire anaerobically They have male and female organs They produce huge numbers of egg (6m a year from cow tapeworm The head (scolex) constantly produces new segments that break off from the tail

21 Tapeworms 2 Tapeworm eggs must develop in the muscles of other animals (pig, cows, fish) before infecting humans The tapeworms form a cyst in the muscle Humans eat undercooked or raw meat and the tapeworm develops in the gut. Tapeworms in the stomach of a dog

22 Malaria Caused by a microscopic animal called a protozoan Transmitted by mosquitoes (they are the VECTORS for this disease) million infected worldwide, annual deaths 2 million

23 Sickle cell anaemia This is a genetic disorder caused by a recessive allele. Faulty haemoglobin is made that changes shape at low oxygen concentrations This causes the red blood cells to sickle and clog capillaries. Sickle cell anaemia protects heterozygous individuals from malaria so the allele is more common in areas that have endemic malaria Normal red blood cell Sickled red blood cell

24 Inheriting sickle cell anaemia The sickle cell allele is recessive (A is normal and a is the sickle allele) Aa individuals are carriers aa individuals are affected Parent 1 Parent 2 A A a a Aa AA Aa aa NormalCarrier Affected

25 Living factories Antibiotics Penicillin made by the fungus Penicillium which is grown in huge fermenters and the fungus secretes the antibiotic into the liquid Enzymes Rennin can come from cows stomachs or fungus and is used in cheese manufacturing Microbes for food Microbes for food is called single celled protein (SCP) Quorn is pressed fungal hyphae

26 Genetic modification (GM) Genes are taken from one species and added to another (e.g. human insulin genes added to bacteria to produce insulin) Human genes are added to bacterial PLASMIDS These are added to another bacterial cell which will produce the human chemical

27 Genetic modification (GM) Genes are taken from one species and added to another in plant crops this may be resistance to disease Against GM cropsFor GM crops Genes could make plant produce toxins Food safety organisations check for these GM crops may irreversibly change the ecosystem Farmers may benefit from healthier crops and lower costs Poor farmers cant afford the seed. Crops are infertile EU consumers wont buy the products Some GM technology shared and yield is bigger Consumers in other countries will buy the products

28 Genetic testing Gene probes are used to test for some faulty genes Faulty genes stick to the probe. These can be seen by UV – a fluorescent molecule sticks to the DNA and glows under UV light Autoradiography – gene probe made from radioactive DNA which blacken X- ray film

29 Blood White blood cell Fight infection. Some produce antibodies, others engulf invaders Red blood cell Carry oxygen in haemoglobin as OXYHAEMOGLOBIN Also present Platelets Cell fragment that trigger blood clotting (not shown here) Plasma The liquid part of blood which also carries nutrients and hormones

30 Blood Types ABO system Blood group O is the universal donor (why) Blood group AB is the universal recipient (why) Giving a patient an incompatible transfusion will cause their blood to clot and kill them! Plasma antibodies will make this happen

31 Inheriting blood groups There are 3 different alleles for this gene A is co-dominant with B A and B are dominant over O Everyone has 2 of these alleles AO and AA are blood group A BO and BB are blood group B AB is blood group AB OO is blood group O

32 Predicting blood groups Parent with blood group AB Parent with blood group O(O) AB O AOBO O AOBO Parent with blood group A(O) Parent with blood group B(O) AO B ABBO O AOOO Group AGroup B Group AGroup B Group AGroup O Group ABGroup B Examples of how blood groups are inherited

33 The heart The heart is really 2 pumps side by side 2 upper chambers are the atria 2 lower chambers are the ventricles Blue represents deoxygenated blood Red represents oxygenated blood Vena cava (from body) Aorta (to body) Pulmonary vein (from lungs) Pulmonary artery (to lungs) Right atrium Left atrium Left ventricle Valve Right ventricle

34 Arteries and Veins Arteries have Thick walls A pulse (pressure waves from the heart beat) Veins have Thinner walls than arteries as the pressure is lower Valves to stop blood flowing backwards

35 Capillaries Have walls one cell thick Have very small diameter (about the size of a red blood cell) Have walls that leak Oxygen and nutrients are taken to the cells Carbon dioxide and waste, like urea, go back into the vessels

36 Double circulation For every trip around the body and lungs, blood must pass through the heart TWICE R VENTRICLE Pumps blood to the lungs LUNGS Blood is OXYGENATED Oxygenated blood returns to the heart L. ATRIUM Pumps blood to LV L.VENTRICLE Pumps blood to the rest of the body CAPILLARIES Blood loses oxygen in the capillaries START RA pumps blood into the RV END Deoxygenated blood returns To RA

37 Respiration Aerobic respiration Glucose+Oxygen+Carbon dioxideWater 6CO 2 6O 2 C 6 H 12 O 6 6H 2 O Aerobic respiration takes place in MITOCHONDRIA

38 Lungs and diffusion Lungs are efficient at getting oxygen into the lungs because them make diffusion efficient Thin walls to the alveoli Large surface area Ventilation of the lungs Diffusion gradient kept high Good blood supply

39 Anaerobic respiration Respiration without oxygen In Plants and Yeast In Human Muscles GlucoseCarbon dioxide Ethanol+ GlucoseLactic acid In both cases some energy is produced (but not as much as in aerobic respiration) and is used to make ATP, the energy currency of the cell

40 Exercise and the oxygen debt Lactic acid builds up during strenuous exercise Removing it from the muscles requires oxygen The amount needed is the oxygen dept

41 The skeleton The skeleton has a number of jobs to do Protects vital organs (brain, spine ovaries) Makes red blood cells in the marrow of long bones Stores the minerals calcium and phosphorus Forms a system of levers with muscles attached for movement

42 Knee joint structure Femur (thigh bone) Tibia (shin bone) Patella (knee cap) Muscle Ligaments Tough elastic tissue holding bones together Tendon Tough and nelastic attaches muscle to bone Cartilage Smooth, covers The end of bones To help movement Synovial fluid Made by synovial Membrane. Lubricates and Nourishes the joint

43 Moving the arm

44 Sports injuries Remember RICE Rest (immobilise the injury) Ice (anaesthetic apply covered) Compression (snugly bandage the injury) Elevation (raise limb to drain fluid) During recover Simple stretching Aerobic exercise

45 The End


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