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B7: Biology Across the Ecosystem

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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 5% passes straight through 35% absorbed By chlorophyll 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 Equation for Photosynthesis Light energy Carbon dioxide + Water Glucose + Oxygen Chlorophyll 6CO2 6H2O C6H12O6 6O2 Light energy splits water into hydrogen and oxygen The reaction takes place in CHLOROPLASTS

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

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

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

11 Compensation point At the compensation point the amount of carbon dioxide produced by respiration is equal to the amount of oxygen being produced by photosynthesis Plants cells produce CO2 all the time (from respiration) There are two compensation points each day

12 The carbon cycle Vegetation

13 Feeding relationships
Oak tree Insect Sparrow Kestrel Producers 1o Consumer 2o Consumer 3o Consumer Producers Herbivore Carnivore Carnivore 1st trophic level 2nd trophic level 3rd trophic level 4th trophic level 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 Soil microbes Approx numbers per gram of soil Bacteria Fungi Nematodes Flatworms Insects 5000

17 Living together 1 Commensalism Mutualism
One organism benefits but the other isn’t 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 ‘Sickled’ red blood cell
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 ‘Sickled’ red blood cell Normal 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 A a AA Aa A Normal Carrier Parent 2 Aa aa a Carrier Affected

25 Living factories Antibiotics Enzymes Microbes for food
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 crops For 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 can’t afford the seed. Crops are infertile Some GM technology shared and yield is bigger EU consumers won’t buy the products 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 Also present 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 Giving a patient an incompatible transfusion will cause their blood to clot and kill them! Plasma antibodies will make this happen Blood group O is the universal donor (why) Blood group AB is the universal recipient (why)

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
Examples of how blood groups are inherited Parent with blood group AB Parent with blood group O(O) Parent with blood group A(O) Parent with blood group B(O) A B A O AB BO AO BO O B Group A Group B Group AB Group B AO BO AO OO O O Group A Group B Group A Group O

33 The heart The heart is really 2 pumps side by side
Aorta (to body) 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 Pulmonary artery (to lungs) Vena cava (from body) Pulmonary vein (from lungs) Left atrium Right atrium Valve Left ventricle Right ventricle

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

37 Respiration Aerobic respiration
Glucose + Oxygen Carbon dioxide + Water C6H12O6 6O2 6CO2 6H2O 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 Glucose Carbon dioxide + Ethanol In Human Muscles Glucose Lactic 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 Muscle Femur Tendon Cartilage Patella Ligaments
(thigh bone) Tendon Tough and nelastic attaches muscle to bone Cartilage Smooth, covers The end of bones To help movement Patella (knee cap) Ligaments Tough elastic tissue holding bones together Synovial fluid Made by synovial Membrane. Lubricates and Nourishes the joint Tibia (shin bone)

43 Moving the arm

44 Sports injuries Remember RICE During recover
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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