Flashcards
B4 - It's a Green World
Cards in this deck (92)
- 1What is a population?All the organisms of one species in a habitat
- 2What is a community?Populations of different species in a habitat
- 3What is the Capture-Recapture method and what is it used for?Capturing a small sample of the population, marking them and releasing them. Capture another sample and be able to estimate the population size by comparing the two samples.
- 4What is the calculation for estimating population size?
- 5What would be the population size if 40 woodlice were captured in the first sample and 50 were captured in the second sample, of which 10 were marked?200
(40 x 50) / 10 - 6How does sample size affect the accuracy of the estimate?The bigger the sample the more accurate the estimate
- 7What 3 assumptions must be made whilst applying the Capture-Recapture method?There have been no changes to the population size
The sampling methods were identical
The marking hasn't affected the individuals chance of survival - 8What is an ecosystem?All the organisms living in a particular area as well as all the abiotic conitions
- 9What is meant by abiotic?Physical factors
e.g. temperature, salinity, soil quality - 10What is meant by biotic?Living factors
e.g. Oganisms - 11What is the difference between a habitat and an ecosystem?A habitat is the area where the organisms live. An ecosystem is all the factors in that area, biotic and abiotic, such as organisms and temperature
- 12What does self-supporting mean?They contain almost everything they need to maintain themselves, such as nutrients, water and essential elements
- 13What is a transect?A line across a part of a habitat
- 14What are transects used for?Finding out the distribution of organisms in a specific area
- 15What is Zonation?The gradual change in distribution of a species across a habitat
- 16What 3 things is biodiversity a measure of?The variation between individuals of the same species in an area
The number of different species in an area
The number of different habitats in an area - 17What is the difference between a natural and artificial ecosystem?A natural ecosystem is able to maintain itself without any major interference from humans
An artificial ecosystem is created and maintained by humans - 18What is the balanced symbol equation for photosynthesis?
- 19How many stages are there to photosynthesis?2
- 20Where does photosynthesis take place?In the Chloroplasts
- 21What happens in the first stage of photosynthesis?Light energy is used to split water into oxygen gas and hydrogen ions
- 22What happens in the second stage of photosynthesis?The carbon dioxide gas combines with the hydrogen ions to make glucose and water
- 23Why isn't water a product of photosynthesis?More gets used up in the first stage than the amount produced in the second stage
- 24Why do plants continuously respire?The plants cells constantly need energy to survive
- 25What two reasons are there for storing glucose as an insoluble starch?The starch cannot dissolve in water and move away from storage areas
It doesn't affect the water concentration inside the cell - 26What 5 things do plants use glucose for?Respiration (energy)
Making Cell Walls (cellulose)
Stored in Seeds (lipids)
Stored as Starch (used for respiration at night)
Making Proteins (Amino Acids for Growth and Repair) - 27How did the Greeks think plants gained mass?From soil minerals
- 28How did Van Helmont think plants gained mass?By taking in water
- 29What did Priestley's experiments show?That plants produce oxygen
- 30What 3 factors limit the rate of photosynthesis?Temperature
Light levels
Levels of carbon dioxide - 31What is diffusion?The net movement of particles from an area of high concentration to an area of low concentration
- 32Why does diffusion occur in liquids and gases?The individual particles are free to move about randomly
- 33What 3 factors affect the rate of diffusion?Distance
Concentration gradient (difference)
Surface area - 34Did you know? Cell Membranes are able to let very small molecules, like simple sugars, water or ions, in and out of the cell. Big molecules like starch and proteins can't pass through.
- 35Label the diagram
- 36What mostly diffuses into the leaf during the day? What mostly diffuses out?Oxygen diffuses out
Carbon dioxide diffuses in
(Due to photosynthesis exchanging gases faster than respiration) - 37What mostly diffuses into the leaf at night? What mostly diffuses out?Oxygen diffuses in
Carbon dioxide diffuses out
(Due to no photosynthesis occurring, just respiration) - 38What 5 ways are leaves adapted for diffusion?The leaves are broad meaning there is a large surface area.
They are thin meaning there is only small distance for particles to diffuse.
The stomata allow gases, like carbon dioxide and oxygen, in and out.
Guard cells are able to control gas exchange by controlling when the stoma opens and closes.
There are air spaces in the spongy mesophyll layer allowing gases to exchange between the stomata and the chloroplasts.
"They have a very big internal surface area to volume ratio." - 39What 5 ways are leaves adapted to absorb light?Being broad allows a large surface area to absorb light.
Contains lots of chloroplasts, these contain a variety of photosynthetic pigments to absorb light energy.
Different pigments allow for a wider variety of wavelengths to be absorbed.
The cells that contain the most chloroplasts are arranged in the palisade layer near the top of the leaf.
The upper epidermis is transparent so that light can pass through to the palisade layer. - 40What are the two transport vessels in plants?Xylem and Phloem
- 41What does the Phloem transport?Food substances, mainly sugars
- 42What does the Xylem transport?Water and minerals up the plant
- 43What is the use of the vascular bundle?To deliver water and nutrients to every part of the plant and take away glucose produced in photosynthesis.
It also helps to support the plant's structure. - 44How do root hairs take in water?Osmosis
- 45What is transpiration?The loss of water from the plant
- 46Describe the 3 stages of transpirationWater vapour is lost from the leaf by evaporation and diffusion
This causes a shortage of water in the leaf, resulting in water being taken by by the xylem to replace it
This causes more water to be drawn from the roots, maintaining a constant transpiration stream - 47What are the 4 benefits of the transpiration stream?The constant stream of water keeps the plant cool
There is a constant supply of water for photosynthesis
The water creates turgor pressure in the cells that helps to support the plant
Minerals are also brought up from the soil with the water - 48What is transpiration rate affected by?Light intensity
Temperature
Air movement
Air humidity - 49How does light intensity affect transpiration rate?The brighter the light, the greater the transpiration rate.
Stomata close when it gets dark. Photosynthesis can't happen at night so they don't need to stay open to let carbon dioxide in.
Water cannot escape when the stomata close. - 50How does temperature affect transpiration rate?The warmer it is, the faster transpiration happens.
When it's warm, the particles have more energy to evaporate and diffuse out of the stomata - 51How does air movement affect transpiration?More wind results in a higher transpiration rate
The wind moves water vapour away from the leaf, leaving a low concentration of water vapour outside the leaf that the water inside the leaf diffuses into more quickly - 52How does air humidity affect the rate of transpiration?The dryer the air outside the leaf, the faster diffusion of water vapour can happen as the concentration is much higher in the leaf than outside
- 53What 3 ways have plants adapted to reduce water loss from their leaves?They have a waxy cuticle covering the upper epidermis that makes the leaf waterproof
Most stomata are found on the lower surface of the leaf where it is darker and cooler, slowing transpiration
The size and number of stomata the plant has depends on it's location. Plants in hot climates will have smaller and fewer stomata to prevent water loss - 54If a guard cell is turgid, is the stoma open or closed?Open
- 55What are the 3 main nutrients plants need?Nitrates, phosphates & potassium
- 56What does the plant need nitrates for?Needed for making amino acids and proteins for growth and repair.
- 57What does a lack of nitrates cause?Poor growth and yellow leaves
- 58What are the use of phosphates?Needed for respiration and growth. Used to make DNA and cell membranes.
- 59What does a lack of phosphates cause?Poor root growth and discoloured leaves
- 60What is potassium used for?Helps the enzymes needed for photosynthesis and respiration.
- 61What does a lack of potassium result in?Poor flower and fruit growth
Discoloured leaves - 62What other mineral is needed, in small amounts, for making chlorophyll?Magnesium
- 63What do root hairs use to take in minerals?Active Transport
- 64How does active transport work?It uses energy from respiration to help pull minerals into the root hair
- 65Why do root hairs have to use active transport?The concentration of minerals is usually lower in the soil so using regular diffusion would cause the root hair to lose nutrients
- 66What 4 things does the rate of decay depend on?Temperature
Amount of oxygen
Amount of water - 67What is the result of these factors being at optimum level?Micro-organisms are able to grow and reproduce faster, speeding up the rate of decay
- 68What do detritivores feed on?Detritus (dead and decaying material)
- 69How do detritivores speed up the rate of decay?They break up the material as they feed on it, leaving a larger surface area for smaller decomposers to work on
- 70How do saprophytes feed on decaying material?Extracellular digestion
- 71What is extracellular digestion?Secreting digestive enzymes that break down the material into smaller bits that can then be absorbed
- 72What are the 6 methods used to reduce the rate of decay?Canning
Cooling
Freezing
Drying
Adding salt/sugar
Adding vinegar - 73How does canning reduce the rate of decay?Keeps decomposers out
- 74How does cooling reduce the rate of decay?Slows the decomposer's reproduction rate
- 75How does freezing reduce the rate of decay?Decomposers can't reproduce at all
- 76How does drying reduce the rate of decay?Decomposers can't carry out reactions without water
- 77How does adding salt/sugar reduce the rate of decay?A high concentration of salt/sugar around decomposers results in the decomposer losing water by osmosis
This damages them and they can't work properly - 78How does adding vinegar reduce the rate of decay?The acidity kills the decomposers
- 79What is intensive farming?Trying to produce as much food as possible from your land, animals and plants
- 80What are 4 advantages to intensive farming?A lot of food is able to be produced from less land
Huge variety of top quality foods
Foods available all year round
Makes prices cheaper - 81What is hydroponics?Where plants are grown without soil
- 82What are the advantages of hydroponics?Mineral levels can be controlled more accurately
Diseases can be controlled more effectively - 83What are the disadvantages of hydroponics?Lots of fertilisers need to be added
There's no soil to anchor the plants and support them - 84What are two instances where hydroponics are used?Growing glasshouse tomatoes on a commercial scale
In areas where the soil is barren - 85What is an advantage of using pesticides?Kills creatures that damage crops
- 86What are 3 disadvantages of using pesticides?Can kill organisms that aren't pests
Can cause a food shortage for animals further up the food chain
Pesticides can be passed on up the food chain, killing animals further up - 87What is biological control?Using living things to control a pest
- 88What are the 2 advantages of using biological control?No chemicals used meaning less pollution, less disruption of food chains and less risk of harm to humans
There's no need to repeat the treatment, unlike with chemicals - 89What are the 4 disadvantages to biological control?The predator may not eat the pest
The predator may eat useful species
The predator's population may get out of control
The predator may not stay in the area where it is needed - 90What are 3 advantages to using organic farming methods?Less chemicals used so less risk of toxins remaining on foods
More environmentally friendly; less chance of polluting rivers, disrupting food chains and haring wildlife
No battery farming, farm has to follow ethical guidelines - 91What are 3 disadvantages to organic farming?Takes up more space than intensive farming
More labour intensive, makes food more expensive
Can't grow as much food - 92How does intensive farming reduce energy loss?Herbicides kill weeds, giving the crops more energy from the sun and not having any competition
Using pesticides kills pests, ensuring that no energy is transferred into another food chain
Battery farming animals saves energy by ensuring the animals are warm and can't move about