Topic 5 - On The Wild Side Flashcards
Define ecosystem…
All of the organisms living in a particular area and all the non living factors.
(Biotic and abiotic)
Define habitat…
The place where an organism lives
Define population…
All the organisms of one species in a habitat
Define community…
All of the organisms of a different species that live in the same habitat and interact with each other
Why does population size (abundance) vary?
Abiotic factors and biotic factors
How do abiotic factors affect abundance by increasing it?
- amount of light, water or space available, the temperature of their surroundings or the chemical composition of their surroundings
- when abiotic factors are ideal for a species they can grow fast and reproduce successfully e.g. when the temp of a mammals surroundings is the ideal temperature for metabolic reactions, they dont have to use up as much energy maintaining their body temp. More energy can be used for growth and reproduction so population increases.
How is abundance decreased because of abiotic factors?
- when abiotic conditions arnet ideal for a species organisms cant grow fast or reproduce as successfully.
-e.g. when the temp of a mammals surroundings is significantly lower or higher that their optimum body temp. This means less energy will be available for growth and reproduction so population will decrease
What are the biotic factors that affect population size?
- inter specific competition
-intraspecific competiton - predation
What is interspecific competition?
Competition between different species
What is the consequence of interspesific competition?
- different species compete for the same resources e.g. food and habitat
- this means that resources available to both species are reduced
- both populations will have less food therefore less energy for growth and reproduction so the population will be lower for both species
What is intraspecific competition?
Competition within a species
What are the consequences of intraspecific competition?
- same species compete for same resources
- the population of the species will increase when resources are plentiful, as population increases there’ll be more organisms competing for the same amount of space and food
- eventually food and space become limiting, there isn’t enough so population begins to decline
- a smaller population means less competiton for space and food which increases growth and reproduction so population starts to grow again
What is carrying capacity in intraspecific competition?
The maximum stable population size of a species that an ecosystem can support
What is predation?
An organism kills and eats another organism.
The population sizes of predators and prey are interlinked, as one changes the other also changes
How does predation affect population?
- as prey increases there’s more food for predators so the predator population grows
- as predator population increases more prey is eaten so prey population falls.
- less food for predators so population decreases
Why does distribution vary?
Abiotic and biotic factors
What is a niche?
The role a species plays within its habitat
What does a niche include?
Biotic interactions - what the organism eats
Abiotic interactions - the oxygen the organism breathes in and the co2 it breathes out
Does every species occupy its own niche?
Yes
Explain the abundance of different species by using the niche concept…
Two species occupying a similar niche will compete so fewer individuals of both species will be able to survive
Explain the distribution of different species by using the niche concept…
Organisms can only exist in habitats where all the conditions to make up their role to exist
Define abundance:
The number of individuals of one species in a particular area
Define distribution:
Where a particular species is within an area you’re investigating
What are the benefits of random sampling?
Reduces bias
What is systematic sampling?
A type of non-random sampling. Where samples are taken at fixed intervals, often along a line
- e.g. quadrants could be placed along a line (transect) in an area where abiotic factors change gradually
What can frame quadrats be used to investigate?
Immobile populations
How do frame quadrats work?
- square frame, usually divided into a grid of 100 smaller squares
- placed on the ground within an area you’re investigating
- in random sampling you can select random coordinates
- the number of individuals of each species is recorded in each quadrat
- the % cover of a plant species can be measured by how much of the quadrat is covered by a plant species
What can point quadrats be used to investigate?
Investigate plant populations
How do point quadrats work?
- horizontal bar on two legs with a series of holes at sent intervals along its length
- places on the ground at random points within the area you’re investigating
- pins are dropped through the holes in the frame abd every plant that the pin touches is recorded
-number of individuals in each quadrat is recorded
How can percentage cover be calculated when using a point quadrat?
Calculating the number of pins that touch a given species and divide this by the total number of pins dropped x 100
What are transects used to investigate?
The distribution of plant populations
How do transects work?
- can figure out how species change over an area
Three types of transect: - line, a tape measure is placed along the transect and the species that touch the tape measure are recorded
- belt transect, data is collected along the transect using frame quadrats placed next to each other
- interrupted transects, instead of investigating them whole transect of either a line or a belt you can take measurements at intervals
What are the three types of transect
- line
-belt - interrupted
What does a kite diagram show?
The abundance and distribution of species
What does the thickness of a kite diagram show?
Abundance
What does the x axis show on a kite diagram?
The distances along the transect line
How do you measure climate?
Temperature - thermometer
Rainfall - rain gauge (a funnel attached to a measuring cylinder)
Humidity - hygrometer
How can you measure oxygen availability?
(Only in aquatic habitats)
- the amount of oxygen dissolved in water can be measured using an oxygen sensor
How can solar input (light intensity) be measured?
By using a light sensor
How can you measure edaphic factors (Soil conditions)?
- ph is measured using indicator liquid, a sample of the soil is mixed with water and indicator liquid changes colour based on the pH and compared to a chart. (PH meters can also be used)
- moisture content, the mass of a sample is measured before and after being dried in an oven at 80-100 degrees (until it reaches a constant mass). This difference as a % of the original mass of the soul is calculated, this shows the water content of the soil
What is topography?
The shape and features of the earths surface
How can you measure topography?
- relief = how the height of land changes across a surface, can be measured by taking height readings using a gps at different points of the surface, you can also use maps with contour lines
- slop angle = how steep a slope is, is measured using a clinometer. A simple clinometer is just a piece of string with a weight attached to the centre of a protractor. You point the flat edge of the protractor up the hill and read the slope angle
- aspect = (the direction the slope is facing) use a compass
What are the three topography features that you need to measure?
- relief
-slope angle - aspect
What is succession?
The process of ecosystem changing overtime
What are the two types of succession and describe them?
- primary succession, happens on land that has been newly formed or exposed e.g. a volcano has erupted to form a new rock surface, or where sea levels have dropped to expose new land. There is no soil or organic material to start with, just bare rock
- secondary succession, happens on land that has been cleared of all plants, but soil remains e.g. after a forest fire or deforestation
Describe the stages of succession…
1) primary succession starts when a species colonise a new land surface, seeds and spores and blown by the wind and begin to grow. The first species to colonise the area are called pioneer species
- abiotic conditions are hostile e.g. no soil to retain water. Only pioneer species grow because they’re specially adapted to cope with harsh conditions
- pioneer species change the abiotic conditions - they die and microorganisms decompose the dead organic material which forms basic soil
- this makes conditions less hostile e.g. basic soil helps retain water which means new organisms with different adaptations can move in and grow. These then die and are decomposed adding more organic material to soil making it deeper and richer in minerals. Larger plants like shrubs can start to grow in the deeper soil which retains even more water.
-some species may change the environment so that it becomes less suitable for previous species.
2) secondary succession happens at a later stage as there is already a soil layer - the pioneer species in secondary stages are larger plants e.g. shrubs
3) at each stage different plants and animals that are better adapted for the improved conditions move in, outcompete the plants and animals that rate already there. They become the dominant species in the ecosystem
4) as succession goes on the ecosystem becomes more complex. New species move in alongside existing species increasing biodiversity
5) the final stage = climax community - the ecosystem is supporting the largest and most complex community of plants and animals it can, it wont change much more - its in a steady state
Do different ecosystems have different climax communities?
Yes - large trees grow in a temperate climate but wont grow in a polar climate
The climax community in a polar climate = herbs or shrubs
How can succession be prevented?
Mowing a lawn
What is the climax community called when it is stopped artificially?
Plagioclimax
What is phosphorylation?
Adding phosphate to a molecule e.g. ADP is phosphorylated to ATP + pi
What is photophosphorylation?
Adding phosphate to a molecule by using light
What is photolysis?
The splitting of a molecule using light energy
What is hydrolysis?
The splitting of a molecule using water e.g. ATP is hydrolysed to ADP
What is the equation for photosynthesis?
6CO2 + 6H20 +energy -> C6H12O6 (glucose) + 6CO2
What is a coenzyme?
A molecule that aids the function of an enzyme, they work by transferring a chemical group from one molecule to another.
What enzyme is used in photosynthesis?
RUBISCO
What coenzyme is used in photosynthesis and how does it work?
NADP - it transfers hydrogen from one molecule to another, this means it can reduce to oxidise a molecule
Draw the structure of a chloroplast
OneNote
What does the chloroplast membrane do?
Double membrane, keeps reactants for photosynthesis close to their reaction sites
What do the thylakoids in chloroplasts do?
Large surface area to allow as much light energy to be absorbed as possible
Stacked up into structures called grana
Lots of ATP synthase present in thylakoid membranes to produce ATP in light dependant reaction
How are granums linked?
By bits of thylakoid membrane called lamellae
What does chlorophyll do?
Coloured substances that absorb light energy needed for photosyntheses
- found in thylakoid membranes
- attached to proteins called photosystems
What are the two photosystems used by plants to capture light energy?
Photosystems I = absorbs light best at a wavelength of 700nm
Photosystems II = absorbs light best at 680 nm
What is the stroma and what is its function?
It’s in the inner membrane of the chloroplast and surrounds the thylakoids, its a gel like substance
- contains enzymes, sugars and organic acids for the light independant reaction
- also contains oil droplets which store non-carbohydrate organic material
What are the two stages of photosynthesis?
Light dependant reaction
Light independant reaction
Where does the light dependant reaction take place?
Thylakoid membranes of chloroplast
Light energy absorbed by photosystems is used for three things in the light dependant reaction…
Making atp from ADP +pi (photophosphorylation)
Making reduced NADP from NADP
Splitting water into protons, electrons and oxygen (photolysis)
What does non-cyclic photophosphorylation produce?
ATP, reduced NADP and oxygen
How are photosystems attached?
Electron carriers
What are electron carriers?
Proteins that transfer electrons
What is an electron transport chain>
A chain of proteins through which excited electrons flow
What are the stages of the light-dependant reaction?
1)light energy excites chlorophyll
2) photolysis of water produces protons electrons and o2
3) energy from excited electrons makes ATP
4) reduced NADP is generated
Draw the light-dependant reaction:
OneNote
What is cyclic photophosphorylation and what does it produce?
Only uses PSI. The electrons from the chlorophyll arnet passed to NADP but are passed back to PSI. Via electron carriers. Electrons are recycled. Only produces small amount of atp.
What is the light independent reaction also called?:
Calvin cycle
Where does the Calvin cycle take place?
Stroma of chloroplasts
What does the light dependant reaction need in order to keep it going and where does it get this from?
H+ ions and ATP, these are from reduced NADP and ATP from the light independant reaction
Draw the Calvin cycle
OneNote
What are the stages of the Calvin cycle?
1) co2 is combined with rubp to form 2 molecules pf gp
2) 2x atp and 2x reduced NADP are required for the reduction of 2x GP to 2x GALP
3) RuBP is regenerated
What organic products can be made from Calvin cycle products?
- carbohydrates (join 2 GALP) polysaccharides (join 2 hexose sugars)
- lipids (glycerol, synthesised from GALP and fatty acids
- amino acids, some made from GP
- nuclei acids, sugar in RBA is used making GALP
How many molecules of GALP produced in the cycle arnet used to make hexose sugars
5/6
