Section 8&9 Flashcards
Exchange of materials
Organisms exchange substances with their environment - they take in substances they need and get rid of waste
Cells need oxygen for respiration with produces co2 - moves between cells and environment through diffusion
How easy it is for an organism to exchange substances with its environment depends on organisms
Surface area:volume ratio
How does urea diffuse
Diffuses from cells to blood plasma for removal by kidneys
Specialised exchange surfaces - the alveoli
Multicellular organisms need exchange surfaces
Gas exchange in mammals happens in the alveoli
The alveoli are adapted for efficient gas exchange- thin walls - big surface area-good blood supply-moist lining for dissolving gasses
Circulatory system - blood
Red blood cells - Carry oxygen No nucleus Large surface area - biconcave White blood cells - fight infection Large nucleus Platelets- clot blood around wounds Plasma- liquid - carries everything except oxygen
Circulatory system- blood vessels
Artery- carry blood away from heart - thick muscle and elastic to withstand high pressure
Vein- carry blood into heart - thinner muscle and elastic - valves prevent backflow
Capillaries- carry blood into muscle and tissue - 1 cell thick, large surface area , gas exchange
Circulatory system
Rv, pa, lung, pv, la, lv, a, body, vc, ra
Left side - thicker as blood goes all over body - oxygenated
Right side - thin as goes to lungs - deoxygenated
Ca= sv X hr
Cats outside ‘are’ sometimes very happy running
Respiration
It’s the process of transferring energy from the breakdown of organic compounds- energy used for contracting muscles, maintains steady body temp, metabolic processes
It’s an exothermic reaction
Cellular respiration releases energy
Measure rate of respiration using a respirometer
Aerobic respiration
Needs lots of energy
Glucose + oxygen -> carbon dioxide + water
Anaerobic respiration
Doesn’t use oxygen
Glucose -> lactic acid(Cramps)
Glucose –> ethanol + carbon dioxide
EcosystemsAnd interactions between organisms
Ecosystems are organised into different levels – individual – population – community – ecosystem
Organisms in the community are interdependent
Environmental changes affect communities in different ways – abiotic and biotic
Use quadrat to see distribution of small organisms use belt transects to study distribution along the gradient
Abiotic
Temperature, light intensity, pollution, water announce
Nonliving factors
Biotic
Food source, predators, bacteria, competition with other Species
Eutrophication
Fertiliser spread on fields
Rain washes it into lakes/rivers
Rapid plant growth
Blocks sunlight and plants at bottom die
Decomposes/bacteria feed on decaying matter using up oxygen
No oxygen means wildlife in rivers/lakes will die
Human impact on biodiversity
Eutrophication
Fish can be found in holding nets in open water
Introduction of non indigenous Species reduces biodiversity
Biodiversity is the range of species in an area
Conservation and biodiversity
Managing biodiversity has many benefits – protect human food supply, providing future medicines, eco-tourism, provide new jobs, cultural aspects
National parks, zoos and artificial habitats protect at risk species
Reforestation can increase biodiversity in deforested areas
Carbon cycle
Green plants use carbon from carbon dioxide to make carbohydrates fats and proteins – eating passes carbon compounds implant to animals in the food chain – both plant and animal respiration releases carbon dockside back into air – plants and animals eventually die and decompose - decomposes break them down and release carbon dioxide back into air by respiration-some useful comments and animal products are burned (combustion
Water cycle
Evaporation
condensation
precipitation
water flows underground
Cleaning water – potable
Desalination – are used to produce water salts from salt (distillation is away)
filter, sunlight, chlorine tablets
Reverse osmosis – used as a Modern method of discrimination – gets rid of impurities in water – salt water filtered then fed at very high pressure into a vessel containing a partially permeable membrane and pressure causes water molecules to move from high to low, as water is forced through, salt is left behind
Nitrogen cycle
- nitrogen fixing bacteria - nitrogen –> nitrates - found in roots of lagooms – (mutualistic relationships)
- Decomposers – nitrates –> ammonium compounds
- Nitrifying bacteria -turn ammonia into nitrites then nitrates
- Denitrifying bacteria - nitrates are converted into nitrogen (often found in waterlogged soils)
How can farmers increase the amount of nitrates in the soil
Crop rotation – instead of growing same crop in the field every year, different crops are grown in a cycle which includes nitrogen fixing crop which helps to put nitrates back into the soil for another crop to use
Fertilisers – recycles nutrients left in plant and animal waste on attendances soil through decomposition
