B4

This section of Biology is named B4:It's a green world. This unit is mainly about plants and how they work and why they work in a particular way. The sections are photosynthesis, ecosystems, zonation, biodiversity,diffusion, osmosis, water flow through plants, transport systems in plants, minerals needed in plants, decay, intensive farming pesticides and biological control, alternatives to intensive farming, estimating population. 

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What does population and community mean?
All organisms of one species that live in a habitat + Populations of different species that live in a habitat
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What is an ecosystem?
It is self-supporting. It is not a habitat, they contain everything you need to need to maintain themselves. Water, nutrients and elements such as carbon get recycled into an ecosystem. They need an energy source such as the sun.
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How do you estimate population size using capture-recapture
Capture a sample and mark it harmlessly, release the animals back into the wild, recapture another sample of the population, count how many of this sample were marked.
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What assumptions must you make when using the capture- recapture method?
No changes in population sizes due to death,immigrations and emigrations. The marking has not affected the individuals chances of survival, the sampling methods for it are identical each time.
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What are transects?
Used to investigate the disruption of organisms
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Why would you calculate the percentage cover when it comes to transects?
It is difficult to count all the individual organism in the quadrat.
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What diagrams how abundance and disruption of organisms
Kite diagrams
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What are Abiotic Factors?
All non living, physical factors in an environment (light,temperature,water,oxygen,salt level and soil quality)
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Why are organisms affected by abiotic factors?
Adapted to live in certain conditions. Many organisms can only survive in certain physical conditions.
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What can lead to Zonation?
Changes in abiotic factors. Zonation is the gradual change in disruption of species across a habitat. It can leads to zones where specific organisms can grow or live.
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What is Photosynthesis?
Photosynthesis is a vital process among photoautotrophs, like plants, algae and some bacteria that are able to create their own food directly from inorganic compounds using light energy
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What are the two main stages of photosynthesis?
First: light enegry is used to split water and oxygen gas and hydrogen ions. Secondly: Carbon-dioxide gas combines with hydrogen ions to make glucose and water.
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What substances can glucose be converted into?
Respiration, making cell walls, turned into lipids stored i the seeds, stored as starch and makes proteins.
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What did Greek scientists think about plant growth?
Plants must gain mass by soil minerals since it was the only thing they were connected to
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What did Van Helmont think about plant growth?
Plants gained mass by taking in water
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What did the Priestley experiments show?
plants produced oxygen
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How did scientists show that oxygen came form water and not carbon dioxide?
Scientists supplied the plant with water containing oxygen-18 ( an isotope). The carbon dioxide the plants received only contained ordinary oxygen 16. When the plants photosynthesised they released oxygen 18.
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what are the threee limiting factors that control the rate of photosynthesis?
Not enough light slows down the rate of ps, too little carbon dioxide also slows it down and temperature has to be just right.
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What is Diffusion?
The net movement of particles from a place of high concentration to the place of lower concentration.
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What does the rate of diffusion depend on?
Distance-move quicker the closer it is, Concentration (gradient) are faster if there is a bigger difference in concentration, SA- more surface avaliable the more they can move around
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Name all of the parts of a typical leaf?
Waxy cutile, upper epidermie, palisade meosophyll layer, chloroplast, lower epidermie, vascular bundle, guard call, stoma, air space, spongy meosophyll layer.
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What is the difference between respiration and photosynthesis?
They are opposite reactions. Photosynthesis can only occur during the day whereas plants respire all the time.
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What do plants exchange by diffusion and how does it work?
Gas! During the day lots of carbon dioxide is usded during photosynthesis and oxygen is being made as a waste product so it needs to diffuse out. At night there is not photosynthesis going on so lots of CO2 diffuses out and O2 diffuses in.
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How are leaves adapted for diffusion?
Large surface areas, thin membranes( short distance) Lower surface is full of stoma. Lets gases in and out easily, guard cells surround the stoma which allows them to control gas exchange, air spaces means a larger SA for gas exchange.
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How are leaves adapted to absorb light?
Broad so it increases SA, more exposed to light. Contain chloroplasts ( that contains photosynthetic pigment) different pigments absorb different wavelength of light, the chloroplasts are arranges in the palisade layer near the top of the leaf.
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What do the network of vascular bundles allow?
Transparent vessels ( xylem and phloem). They deliver water and other nutrients to every pert of the leaf and take away the glucose produced by photosynthesis. They also help to support the leaf structure.
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What is osmosis?
The net movement of water particles form a place of high concentration to a place of lower concentration through a semi-permeable membrane.
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How does turgor pressure support plant tissue?
The contents of the cello push against the inelastic cell wall- this is called turgor pressure. Turgor pressure helps support the pant tissue.
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What does it mean if a cell is lysis?
A cell takes in too much water and bursts
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What does it mean if the cell is crenation?
Loses too much water and shrivels up
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What are the phloem tubes?
Made of columns of living cells with perforated end-platres to allow stuff through. It transports food to all parts of the plant, The movement is known as translocation.
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What are Xylem vessels?
Made of dead cells joined end to end, no walls between them and a lumen down the middle. Thick walls made of cellulose, they are strong which gives the cell support. It takes water up. It moves the water and minerals by the transpiration stream.
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Name 3 examples where the vessels are found?
Root cross-section, stem cross-section and leaf cross-section
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How do root hairs take in water by osmosis?
There are millions of these hairs all over the plant which gives them a huge surface area, since there will be a high concentration of water in soil it means that osmosis will occur as there will be a lower concentration of water in the plant.
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Explain transpiration?
It is caused by evaporation and diffusion of water vapour from inside the leaves. This creates a light shortage of water so it needs to keeps being drawn by by the xylem vessels to replace the lost water.
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What are the advantages of transpiration?
The constant stream of water keeps the plant cool, it provides a constant supply of water for photosynthesis, the water creates turgor pressure in the plant cells, minerals needed by the plant can be brought up by the constant water supply.
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What four main factors increase transpiration?
Increase of light intensity, increase of temperature, increase of air movement, decrease of air humidity.
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How does light intensity increase transpiration rate?
The stoma close when it is dark the brighter it is the more open they are which means more water can be diffused or evaporated.
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How does temperature effect transpiration rates?
When it's warm the water particles have more energy to evaporate or diffuse out of the plant.
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How does Air movement effect transpiration?
There will be a higher concentration of water particles outside the leaves the more air movement there is, which means diffusion will occur quicker.
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How does air humidity effect transpriation?
The dryer the air outside the less diffusion will occur, so the less humid the air outside the more diffusion will occur because the higher concentration will be inside the leaf so the water will diffuse out of the leaves to move to a place of less.
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Why do plants need to balance water loss with uptake?
It has not been raining so the plant needs to reduce water loss! Stoma are found on the lower part of the leaf where it is darker and cooler so this reduces diffusion.Plants in hotter climates have smaller stoma to reduce water loss.
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Why do stoma open and close automatically?
Open stoma allow gases in and our for photosynthesis. They're sensitive to light, so they open during the day and close at night. This allows them to conserve water without losing out on photosynthesis
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What mineral are needed for healthy growth and why?
Nitrates- making amino acids & protein, cell growth. If no nitrates leaves will turn yellow. Phosphates- repiration and grwoth, making DNA and membranes. Without means poor root growth. Potassium- enzymes. Without means poor flower/fruit growth
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Why is magnesium needed in small amounts when it come to healthy growth?
Needed for making chlorophyll. This gives plants the green colour, without this the leaves will be yellow.
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Why does micro-organisms make things decay?
Decomposition is done by micro-organisms like soil bacteria and fungi. These are known as decomposers.
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What are detritivores and Saprophytes?
They are both types of organism that are importand in decay. They are grouped into those types of group depending how they feed.
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How do Detritivores feed?
dead and decaying materials. include earthworms,maggots and woodlice. They break up into smaller bits. This gives a bigger SA for small decomposers to work on.
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Howe do Saprophytes feed?
By extracelluar digestion. They feed by secreting digestive enzymes on to material outside of their cells. They break down the materail into smaller bits which can be absorbed by the saprophyte. Example is fungi
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What is intensive farming?
Trying to produce as much food as possible from your land, animals and plants. The ways they can do this is: using herbicides to kill weeds, using pesticides to kill insects and battery farming animals.
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Advantages of intensive farming?
Mineral levels can be controlled more accurately. Diseases can be controlled more effectively.
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Disadvantages of intensive farming?
Lots of fertilisers need to be added. There's no soil to anchor the roots and support the plants.
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How can intensive farming destroy the environment?
Removal of hedges can destroy natural habitats for animals. Eutrophication. Pesticides can disturb food chains. People think it is cruel because animals have a small amount of movement space.
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How to pesticides disturb food chains?
Kill animals that aren't pests, Shortage of food for animals further up the chain. Some are persistent and stay around for a log time. Danger of pesticides being passed along the food chain
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What is biological control?
Using living things instead of chemicals to control a pest. An example would be to release a particular animal that would eat the pest.
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What are the advantages of biological control?
no chemicals are used so less pollution, less disruption of food chains and risk to people eating infected food. No need to keep repeating the treatment.
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Disadvantages of biological control?
The predator might not eat the pest. The predator could eat useful species. The predator population might increase and get our of control. The predator might not stay in the area.
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Name some alternatives to intensive farming?
Organic farming methods, use organic fertilisers, crop rotation, weeding, varying seed planting type, biological control
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Advantages to organic farming methods?
Fewer chemicals, better for the environment, no use of pesticides, ethical treatment of animals, more jobs.
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Disadvantages to organic farming methods?
Takes up more space, more labour-intensive, food more expensive, not as much food can be grown.
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Other cards in this set

Card 2

Front

What is an ecosystem?

Back

It is self-supporting. It is not a habitat, they contain everything you need to need to maintain themselves. Water, nutrients and elements such as carbon get recycled into an ecosystem. They need an energy source such as the sun.

Card 3

Front

How do you estimate population size using capture-recapture

Back

Preview of the front of card 3

Card 4

Front

What assumptions must you make when using the capture- recapture method?

Back

Preview of the front of card 4

Card 5

Front

What are transects?

Back

Preview of the front of card 5
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