Biology, Module 4
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?- Created by: RiyaPatelx
- Created on: 30-05-13 13:07
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- ECOLOGY IN THE LOCAL ENVIRONMENT
- DISTRIBUTION OF ORGANISMS
- Ecosystem - made up of all plants and animals living there and their surroundings.
- Natural Ecosystem - (large biodiversity) eg. native woodlands and lakes
- Artificial Ecosystem - (poor biodiversity) eg. forestry plantations and fish farms
- Humans deliberately keep and protect only one species and remove any other organisms that would compete with it and lower the yield.
- Created by humans for the benefit of humans
- Biodiversity - the range of different living organisms in a habitat.
- Habitat- where a plant or animal lives
- Zonation - gradual change in species distribution across a habitat.
- Community - animals and plants living in a garden
- Population - number of a particular plant or animal present in the community
- Transect line - a long length of string is laid across an area such as a path or sea shore.
- Quadrat - at regular intervals the organisms in a square frame are counted (for animals) or the percentage of (plants) covered.
- This data can be displayed in a kite diagram.
- Some animals are trapped, for example, using pitfall traps. They are marked in a harmless way then released. Traps are used a few days later. The number of marked and unmarked animals caught in the traps are recorded.
- Population size = number in 1st sample x number in 2nd sample / number in 2nd sample previously marked
- Ecosystem - made up of all plants and animals living there and their surroundings.
- DISTRIBUTION OF ORGANISMS
- PHOTOSYNTHESIS
- THE CHEMISTRY OF PHOTOSYNTHESIS
- Photosynthesis = water + carbon ---> oxygen + glucose
- Glucose - (simple sugar)
- can be used in respiration, releasing energy
- converted into cellulose to make cell walls
- converted into proteins for growth and repair
- converted into starch, fats & oils for storage
- Starch is used for storage since it is insoluble.
- Photosynthesis is a two-stage procress
- water is split up by light energy releasing oxygen gas and hydrogen ions
- carbon dioxide gay combines
- water is split up by light energy releasing oxygen gas and hydrogen ions
- Historical understanding of photosynthesis
- Photosynthesis = water + carbon ---> oxygen + glucose
- RATE OF PHOTOSYNTHESIS
- can be increased by:
- more carbon dioxide
- more light
- higher temperature - increases enzyme action
- Photosynthesis will only take place during daytime (in the light). However, plants respire so it releases energy at all times.
- Plants respire at all times by taking in oxygen and releasing carbon dioxide.
- can be increased by:
- Photosynthesis relies on light, temperature & carbon dioxide..a lack of these will affect the rate of it (limiting factors).
- LEAVES
- Upper Epidermis - transparent to allow light through
- Cuticle (wax layer) - waterproof, less water loss
- Palisade layer - contains chloroplasts
- Spongy mesophyll layer - contains air spaces so they can respire & photosynthesis
- Guard cell - open + closes the stoma
- Stoma (pore) - allows CO2 in and H2O out
- Lower epidermis
- Large surface area = as much light as possible
- Thin so gases can diffuse through easily
- THE CHEMISTRY OF PHOTOSYNTHESIS
- LEAVES
- Upper Epidermis - transparent to allow light through
- Cuticle (wax layer) - waterproof, less water loss
- Palisade layer - contains chloroplasts
- Spongy mesophyll layer - contains air spaces so they can respire & photosynthesis
- Guard cell - open + closes the stoma
- Stoma (pore) - allows CO2 in and H2O out
- Lower epidermis
- Large surface area = as much light as possible
- Thin so gases can diffuse through easily
- DIFFUSION AND OSMOSIS
- DIFFUSION
- Diffusion - net movement of particles in a gas or liquid from an area of high concentration to an area of low concentration.
- The rate of diffusion is not a fixed quantity. It can increased by:
- short distance for the molecule to travel
- steeper concentration gradient
- greater surface area for the molecules to diffuse from, or into
- OSMOSIS
- Osmosis - movement of water across a partically - permeable membrane from an area of high water concentration to an area of low water concentration.
- It's a type of diffusion
- DIFFUSION
- TRANSPORT IN PLANTS
- XYLEM AND PHLOEM CELLS
- Xylem and Phloem are made up of specialized cells. Both are types of tissues and are continuous from the roots, through the stem and into the leaf.
- Form Vascular Bundles
- XYLEM
- carry water & minerals from the roots to the leaves and therefore involved in transpiration.
- PHLOEM
- carry food substances such as sugars up and down stems to grow and storage tissues - (translocation).
- XYLEM AND PHLOEM CELLS
- DECAY
- Decay - when dead animals and plants break down
- Ideal conditions for decay:
- tempetature
- water (lots)
- competition with oxygen (lots)
- Detritus - dead and decaying plants/animals
- Detritvores - animals that break down detritus into smaller pieces
- Saprophyte - feed on dead / decaying
- Aerobic Bacteria - more oxygen (+respiration)and more decay
- Ideal conditions for decay:
- Decay - when dead animals and plants break down
- FARMING
- Intensive Farming - producing large crops yields cheaply
- Biological Controls - when they get other animals to eat animals
- Organic Farming - use biological control
- seen as healthier
- PLANTS NEED MINERALS
- USE OF MINERALS
- Plants need minerals, such as:
- Nitrates, to make proteins, which plants use for cell growth
- Phosphates, which are involved in respiration and growth
- Potassium compounds, which are involved in respiration and photosynthesis
- Elements from soil minerals are used to produce useful compounds:
- Nitrogen is used to produce amino acids, which combine to form a variety of proteins
- Phosphorus is used to make DNA, which contains the plants genetic code, and cell membranes
- Potassium is used to help enzyme action in photosynthesis and respiration; enzymes speed up chemical reactions.
- Maganesium is used to make chlorophyll, which is essential for photosynthesis
- Mineral uptake involves active transport, rather than diffusion or osmosis.
- Plants need minerals, such as:
- USE OF MINERALS
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