B7-Ecology AQA set Flashcards
What is classification?
The science of grouping organisms into taxons where those with similar characteristics are grouped together
Who suggested the five kingdoms?
Carl Linneaus
What are the five kingdoms?
- Animals
- Plants
- Fungi
- Protists
- Bacteria
Name the classification system in order:
Domain Kingdom Phylum Class Order Family Genus Species
What is a species?
A group of similar organisms that can successfully breed together and produce living fertile offspring
How are species identified?
By a Binomial Name
Who introduced the three domains?
Carl Woese
What enabled Carl Woese to introduce the three domains?
The improving methods of testing and viewing organisms with microscopes and the consequent changing of classifications
What are the three domains?
- Eukarya
- Prokarya
- Archaea
What does the Eukarya domain contain?
Organisms with cells that contain a nucleus
What does the Prokarya domain contain?
Organisms that lack a nucleus
What does the archaea domain contain?
Primative bacteria found living in extreme environments
Why have classification systems changes over times?
Due to the improvements in biochemistry and microscopy
What information do scientists use to draw phylogenetic trees?
Classification information- observable features, biochemicals (e.g. DNA)
Fossil records
What is the alternative name for the phylogenetic tree?
Evolutionary tree
Compare the major features of organisms from the plant and animal kingdom
- Animals can move their whole bodies from place to place whereas plants cannot move their whole bodies about
- cells of plants have a cellulose cell wall however the cells of animals do not have a cell wall
- plants can carry out photsynthesis to produce food whereas animals have to eat food
What do the community of organisms within an ecosystem do?
Interact with each other in a variety of ways
What is an ecosystem?
It’s the interaction of all organisms and non-living organisms , within a community including both biotic and abiotic
What is a community?
All the different populations of different organisms in an ecosystem with their own habitats
What are biotic factors?
Living
What are abiotic factors?
Mon-living
Give required examples of biotic factors:
- New pathogens
- Competition
- Predation
- Food supply
- Parasitism
Give required examples of abiotic factors:
- Wind intensity
- Soil pH
- Light intensity
- Mineral content
- Oxygen levels (aquatic animals)
- Moisture levels
- Wind direction
- Temperature
- CO2 levels (plants)
What do biotic and abiotic factors affect?
The population sizes of organisms
What does each organism rely upon others for in a community?
- food
- habitat/shelter
- pollination
- seed dispersal
What is a stable ecosystem?
Where there is a balance in population sizes due to interdependence
What do plants compete with eachother for within a community or habitat?
- light
- mineral ions
- water
- space
What do animals compete with eachother for within a community or habitat?
- territory
- food
- mates
What is the theory behind natural selection?
The most successful competitors are those that are best adapted , so will survive, breed and pass these adaptations onto the next generation
What is an adaptation?
A feature of a living organism that enables it to survive in its natural habitat. Often they provide a selective advantage
What are extremophiles?
Organisms (commonly bacteria and archaea) that are adapted to extreme hostile environments
What are some examples of extrme hostile environments?
- High temperatures
- High salt levels
- High pressure
What are the three types of adaptations?
- Structural
- Behavioural
- Functional (biochemical)
How are larger animals adapted to colder environments
They have a smaller surface area to volume ratio so they lose less heat energy
Where does energy in ecosystems originally come from?
The Sun
How is energy transferred in an ecosystem?
From plants to animals and then animals to animals before being lost to the environment
What does a food chain represent?
The flow of energy
How is energy lost at each trophic level?
Loss through respiration (e.g. heat)
Production of faeces and urine
What is the largest typical length of a food chain? Why?
5 organisms because so much biomass/energy is lost from the food chain at each stage, through uneaten material, waste products, faeces, energy for movement and keeping warm
What is the most energy efficient diet? Why?
Vegetarian as the most energy is consumed since it is direct from a producer
Whats the relationship between the number of predators and prey?
If the number of predators increases, inevitably the number of prey falls and vice versa. In nature, this occurs in regular cycles
What are the properties of a producer?
- Largest mass
- First trophic level
- Most energy
- Photsynthetic
What are the properties of a primary consumer?
- Herbivore
- Second trophic level
- Prey
What are the properties of a secondary consumer?
- Prey
- Predator
- Third trophic level
- Carnivore
What are the properties of a tertiary consumer?
- Top predator
- Least energy
- Carnivore
- Smallest mass
- Fourth trophic level
What must be done when sampling an ecosystem?
Sites are chosen randomly to remove bias
What piece of equipment is used in sampling?
A quadrat
How do we know where to place the quadrat for our sample?
Make a grid and use a random number generator to choose co-ordinates
How can the validity of a sample area be improved?
By taking more measurements
Aside from (a)biotic factors, what do ecologists look at ?
- The abundance of organisms
- The distribution of organisms
What is a quadrat used for?
To estimate the population of plants in an area
What is a line transect used for?
To show how the distribution of organisms changes between two points
How do you carry put a line transect?
Choose a random starting location, make a line of quadrats and record the distance and the number of organisms found
What happens to nutrients in an ecosystem?
They are naturally recycled
What are the two nutrient cycles?
Water
Carbon
Why do plants need space for healthy growth?
So the roots can take in enough water and minerals. It also means that the leaves can capture enough light for photosynthesis.
Why does a plant need water for healthy growth?
To keep tissues rigid and to photosynthesise
Why does a plant need light for healthy growth?
In order for it to use the energy from the light to photosynthesise and produce food
Why do plants need minerals for healthy growth?
To make amino acids and protein and other molecules necessary for growth
Why do cacti have roots which spread far from the plant?
To cover more area than other plants in the soil for water uptake to avoid competition
Why does ivy have suckers which help it grow up structures?
It means the ivy reaches an area of fewer plants so gets more light shining on leaves for photosynthesis
Why do some animals mark their territory?
To stop other members of their species entering, which stops competition for food or mates
How does being an omnivore, enable a species to survive?
It means they can eat more different types of food so therefore they experience less competition for food
Why do plants (e.g. cactus) not necessarily require oxygen?
Because the plant photsynthesises which produces oxygen that it can use
Why do all organisms need water?
It is needed for cells to function and aids the transport of other substances in multicellular organisms
How are enzymes adapted which are in microorganisms that live in high temperatures?
Their enzymes do not denature at a high temperature so they can still carry out the essential reactions at high temperatures e.g. respiration
Why do some plants have spines?
To protect the plant from other animals which could eat it and to reduce water loss by evaporation
What are common adaptations of plants?
- Low surface area to volume ratio in hot conditions for decreased water loss from leaves
- spines for protection from herbivores
- extensive root systems to collectas much water as possible
- storing water in tissues so water is available at all times even in periods of dry weather
By what processes does water vapour get into the sky?
- Evaporation
- Excretion
- Respiration
- Transpiration
- Combustion
What happens to water vapour in the sky?
It condenses to produce clouds
What are the types of precipitation?
Rain, hail, snow, fog, mist, dew
What moves clouds?
Wind
What is percolation?
The slow movement of water through a solid
What is excretion?
The removal of chemicals, particularly poisons
What process does water undergo with roots?
Absorption
What drives the water cycle?
The heat energy from the sun
Where is carbon found?
In all organic molecules including carbohydrates, lipids and proteins
How is biomass related to carbon and energy?
More biomass = more carbon = more energy
What are decomposition and decay responible for?
Recycling carbon, nitrogen and minerals needed for living organisms
What are most decomposers?
Fungi and bacteria
What process do fungi and bacteria do to decompose stuff?
Extracellular digestion
What is extracellular digestion?
the secretion of digestive enzymes and absorption of the digestive products back into their cells
What factors does decay rely on?
- availability of oxygen
- temperature
- availability of water
What are the methods to prevent decay?
- canning or sealing food
- fridges
- dessication (drying) or curing food
What happens when milk decays?
The bacteria digest the lipids releasing fatty acids, these fatty acids will reduce the pH. A big enough reduction in pH will denature the proteins in the milk, causing it to curdle
Describe the required practical for decay:
- put lipase solution in one test tube
- put a few drops of Cresol red solution, some milk and sodium carbonate into another test tube using a dropping pipette
- put a thermometer into the second test tube
- get the contents in the test tubes to the desired temperatures using a water bath
- use another dropping pipette to transfer lipase into the milk test tube
- start timing
- stir the contents until the colour of the solution goes from purple to yellow
- record the time taken for the colour change
- repeat at all temperatures
describe the importance of decay in the carbon cycle
carbon dioxide is returned back into the atmosphere when the microorganisms involved in decay respire
Why are there more likely to be more herbivores than carnivores in a community?
More energy is available to them so more can be supported
What do enzymes secreted by bacterial decomposers do?
Break down waste material into soluble food molecules which then diffuse into the bacterial cells
What happens when bacterial decomposers decay waste?
They return mineral ions to the soil
What is the impact on biomass transfer when the activity of bacterial decomposers is reduced?
- if the rate of activity of decomposers is reduced, there will be fewer mineral ions in the soil which may mean that plants don’t grow as well/quickly
- this means there are fewer/smaller plants in the woodlnad, meaning the biomass of the producers is less
- this means less biomass is available for the primary consumer, so less of that will be available for the secondary consumer etc.
How is biomass lost in respiratory losses?
- glucose is used in respiration meaning it’s not used to make more biomass
- during repsiration, carbon dioxide and water are lost as wast products too
Why do gardeners and farmers try to provide optimal conditions for decay?
To maximise the rate at which nutrients are recycled and the compost produced is then used as a natural fertiliser to aid plant growth
What is produced during anaerobic decay?
Methane
What is the advantage and disadvantge of the production of methane during anaerobic respiration?
- methane gas can be collected and used as a fuel
- methane gas can cause environmental problems (greenhouse house)
What is biogas often used for?
- generating electricity on sewage farms-
- has even been used to power UK buses
What is a habitat?
The place where a particular organism lives
what does the arrow in a food web/chain represent?
the direction of the transfer of energy from one organism to another
What is the advantage of a food web over a food chain?
- a food web is more accurate as it shows the network of interactions between organisms
- a food web shows all or many of an organism’s predators or prey whereas a food chain only shows one
Why is the sun necessary for an ecosystem which is stable and self-supporting?
- the Sun provides the energy for photosynthesis
- photosynthesis makes glucose and oxygen
- glucose serves as a food for animals
- oxygen is used for respiration by living organisms in the ecosystem
How can an invasive species cause a decline in a native species?
- by preying upon the native species
- outcompeting it for food or other resources
- causing or carrying disease
- preventing the native species from reproducing or killing their young
Why is there a delay in the impact when the population size of a predator/prey increases?
- because they are responding to changes in the previous generation of the other population
- neither population can respond instantly to changes in the other
- reproductive cycles in either population cause a delay in response
What is a structural adaption?
a physical feature of an organism which helps it survive
What is a behavioural adaption?
a thing which an organism does to survive
What is a functional adaptation?
a change to the way an organism works that helps it becomes more favourable to a certain environment (biochemical)
Describe the water cycle:
- water evaporates from the land and sea using energy from the sun
- water also evaporates from plants during transpirationand becomes water vapour
- the water vapour rises up and cools due to lower pressure, and condenses forming clouds
- eventually the water falls as precipitation onto the land and into the sea
Why is the water cycle important for living organisms?
- every living organism on Earth depends on water to survive
- without water and the water cycle to circulate water, all living organisms would die very quickly
- it is needed for chemical reactions in living things such as respiration and photosynthesis
What factors would affect the amount of carbon dioxide concentration in the air?
- the varying seasons/weather as it means different amounts of photosynthesis takes place meaning there are different rates of carbon dioxide removal
- amount of carbon dioxide stored in the oceans might change according to air temperature
- amount of combustion taking place could also affect the amount of carbon dioxide being releases
Why is decay vital for life?
vital nutrients for life would remain locked in dead organic materials if there was no decay
Why does temperature affect the rate of decay of milk?
- increasing the temp to a certain point, increases the rate of reaction by increasing the collision rate between the enzyme and substrate molecules
- past a certain point, increasing the temp, reduces the rate of enzyme reactions until it stops when the active site of the enzyme is denatured by the high temperature and so the enzyme cannot break down the lipids
Why is the efficiency of biomass transfer between different trophic levels typically low?
- not all organisms in one trophic level are eaten by the next
- some parts of organisms are inedible
- some organisms may die before being eaten so decompose and their energy is passed to the decomposers
- not all eaten food is digested and not all digested food is absorbed, some is egested as faeces
- lots of energy is lost through excretion and cell respiration to provide energy for movement and keeping warm rather than making biomass
