B4- ECOLOGY IN THE ENVIRONMENT

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ecosystems

Ecosystem- physical environment with a particular set of conditions + all organisms. self supporting

Habitat- part of a physical environment where an animal or plants live

Community- total numbers of all individuals living in one habitat at one time

Population- total number of all individuals of the same speices in a certain area

Natural ecosystems

  • high biodiversity
  • different plant and animal species coexisting in the same environment

Artificial ecosystems

  • designed for a particular purpose
  • lower biodiversity
  • weed killers, fertilisers and pesticdied and used
  • eg fish farms, greenhouses
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Sampling methods

Sampling methods

Pooters- containers used to collest insects. without harm

Sweepnets- used to collet insects in long grass or dense woodland

Pitfall traps- containers set in the ground to catch small insects

Quadrats- square frames used to count a small proportion of the population

When sampling:

  • big enough sample
  • random
  • representative
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Photosynthesis

Carbon dioxide + water  --> glucose + oxyge

  6CO2             + GH20  -->C6H12O6 + 6O2

Glucose and starch can be converted into-

  • energy
  • protein for growth and repair
  • starch, fats oils that can be stored in seeds
  • cellulose, needed for cell walls

Glucose is soluble. It can be transported around the plant as sugar. but it must be converted into starch, which is insoluble, in order to be stored.

Starch is a very useful storage molecule, it is insoluble so it doesnt affect the water concentration inside the cell when stored, also it does not move. If the cells stored soluble glucose the inside of the cells would become very concentrated and water would constantly move in through osmosis, which can make the cell swell.

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Increasing Photosynthesis

Plants need light and warmth to grow

Can be increades be increasing-

  • the temperature- limiting factor, as it approaches 45c the enzymes start to denature and rate of photosynthesi declines to zero
  • the light intensity- limitng factor, increases photosynethesis to a certain point and then has no impact
  • the carbon dioxide concentration-limiting factor, increases photosynethesis to a certian point and then it no longer has an impact

During day - light is available from the sun so plants can photosynthesis, taking in carbon dioxide to make glucose and realeasing oxygen as a by-product

During the day and night- plants respire absobing oxygen and giving out carbon dioxide. Respiration is the opposite of photosynthesis

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Plants

Leaves:

  • contain a pigment of chlorophyll in million of chloroplasts, plus other pigments to absorb light from different parts of the spectrum
  • are broad and flat, to create a large surface area, to absorb sulight
  • have a network of vascular bundles for support + transport water to cells + remove glucose
  • have a thin structure so gases can travel in + out of the cells easily
  • have stomata on the underside of the leaf to allow exchange of gases, opened and closed by guard cells. During photosynthesis carbon dioxide diffuses in through stomata and oxygen diffuses out 
  • UGLY    
  • ELEPHANTS
  • PERSUADE
  • LITTLE
  • SUZY
  • MEN
  • LIKE
  • ELLA
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Diffusion

Substances move in and out of the cell membrane by diffusion, which is the movement of a substance from a region of high concentration to a region of low concentration.

Rate of diffusion is increased by-

  • greater surface area of cell membrane
  • greater difference in concentration
  • particles have a smaller distance to travel

Diffusion in plants

  • carbon dioxide is used up in photosyntheis, concentration inside the leaf is lower than the concentration outside the leaves
  • carbon dioxide diffuses into the plant through the stomata
  • oxygen, product of photosynethesis diffuses from the plant into the atmosphere
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Diffusion

Substances move in and out of the cell membrane by diffusion, which is the movement of a substance from a region of high concentration to a region of low concentration.

Rate of diffusion is increased by-

  • greater surface area of cell membrane
  • greater difference in concentration
  • particles have a smaller distance to travel

Diffusion in plants

  • carbon dioxide is used up in photosyntheis, concentration inside the leaf is lower than the concentration outside the leaves
  • carbon dioxide diffuses into the plant through the stomata
  • oxygen, product of photosynethesis diffuses from the plant into the atmosphere
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Diffusion

Substances move in and out of the cell membrane by diffusion, which is the movement of a substance from a region of high concentration to a region of low concentration.

Rate of diffusion is increased by-

  • greater surface area of cell membrane
  • greater difference in concentration
  • particles have a smaller distance to travel

Diffusion in plants

  • carbon dioxide is used up in photosyntheis, concentration inside the leaf is lower than the concentration outside the leaves
  • carbon dioxide diffuses into the plant through the stomata
  • oxygen, product of photosynethesis diffuses from the plant into the atmosphere
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