Populations and ecosystems A01 Flashcards
Habitat and niche
Place an animal lives vs role an organisms plays
Biotic and abiotic
Living vs non-living factors
Population and community
a group of individuals of the same species living within an area vs an interacting group of various species in a common location.
Ecology and ecosystem
Study of the relationships between living organisms vs a community of living organisms in a particular area.
List 4 factors that affect how large a population is
Birth rate, death rate, emigration and immigration
Using the letters B,D,E and I write an equation for a stable population
B+ I= D +E
What will happen to the size of the population if the birth rate exceeds death rate?
Increase
Why is it not appropriate to use the term “birth” for populations of single-celled organisms like yeast, bacteria and paramecium? What term might be more appropriate?
They produce individuals using binary fission.
State a factor that could slow the population growth and one that could cause a population crash.
Food or nutrient limitation and a forest fire
What is meant by the term “carrying capacity”?
Carrying capacity is the maximum number of individuals of a species that an environment can support.
Define density dependent
any force that affects the size of a population of living things in response to the density of the population.
Define density independent
Any force that affects the size of a population of living things regardless of the density of the population.
Name two density dependent factors and two density independent factors.
Disease, competition and predation
And
Food or nutrient limitation, pollutants in the environment, and climate extremes.
The fall in living bacteria is because they have been heated. Is this a density dependent or independent factor?
Density independent
What is the advantage of using log values when graphing populations of bacteria?
Let’s you identify a pattern when there are large value changes
What type of sampling would you use to investigate an area with an ecological gradient?
Line/belt transect
Describe how you would carry out an investigation of an area’s ecological gradient
Placing a measuring tape along the shore line then placing a quadrat at different distances along this line and recording the species and their numbers.
How could you present the data for an ecological gradient?
Kite diagram
Which type of sampling would you use to investigate the effect of aspect on two sides of a hill?
Quadrat sampling
Describe how you would carry out an investigation for the effect of aspects on two sides of a hill
Place two measuring tapes across an area like two axes of a graph. Then use a telephone number or a random number generator to make random coordinates. Place the quadrants in the random area.
What calculation could you perform to assess the biodiversity in two areas?
Simpsons diversity
What data would you need to collect to perform the calculation?
Number of individual species in each area.
How could you improve the reliability of the data?
Use more Quadrat samples
What is the source of energy for most ecosystems?
Light
Define GPP
The amount of chemical energy which is created from light energy in a given amount of time.
Define NPP
The chemical energy stored in plant biomass after respiratory losses.
Write an equation to illustrate the relationship between NPP and GPP
NPP= GPP- R
How is energy “lost” from each trophic level?
90 % of energy may be lost as heat (released during respiration), through movement, or in materials that the consumer does not digests.
Define succession
The process by which the mix of species and habitat in an area changes over time.
What is a seral stage?
A stage in succession
Name the seral stages for a primary succession starting with bare rock.
Pioneer species through to climax communities
What is the role of immigration in succession?
The presence of an initial species aids and increases the probability of the growth of a second species.
What happens to species diversity and the stability of ecosystems as a succession progresses?
Both increase
What is the difference between primary and secondary succession?
Primary succession occurs in an environment without previous life, or barren habitat. Secondary succession occurs in an area that had previously been inhabited but experienced disturbance.
What would be the independent variable in an investigation into succession?
Time
How would you carry out an investigation into succession?
Observe/record species over time
What would you “measure” in an investigation into succession?
Number of individuals in each species
What is the role of detritivores in an ecosystem?
Break down dead organic matter
What modes of nutrition do detritivores have?
Heterotrophic- holozoic
What is the role of plants in nutrient cycling?
Absorb nutrients from soil so that they can re-enter the food chain.
Why do plants need the following: nitrates, phosphates, sulphate and carbon dioxide?
Nitrates- plant protein
phosphates- need to make DNA from cell membranes
Sulphate- plant protein formation
Carbon dioxide- photosynthesis
How are mineral ions absorbed into root hairs?
Active transport
How do mineral ions get transported throughout the plants?
Up the xylem dissolved in water
By what process is carbon dioxide removed from air by plants?
Photosynthesis
Give the names of two processes that return carbon dioxide to the atmosphere
Combustion and respiration
Explain two human activities that increase global carbon dioxide levels
Burning fossil fuels and deforestation
Explain why increasing carbon dioxide levels are increasing global temperatures
Carbon dioxide is a greenhouse gas
Define carbon footprint
The total amount of greenhouse gases (including carbon dioxide and methane) that are generated by our actions.
Explain why humans should do the following to halt climate change: Not fly
Reduces fossil fuel use
Explain why humans should do the following to halt climate change: Not drive
Reduce fossil fuel use
Explain why humans should do the following to halt climate change: Reduce electricity use
Reduce fossil fuel use
Explain why humans should do the following to halt climate change: Be vegan
More energy is needed to produce meat
Explain why humans should do the following to halt climate change: Buy locally produced groceries in season
Reduce fossil fuel use in transporting produce
What is a planetary boundary?
A framework to describe limits to the impact of human activities on the Earth System
Outline the effects of crossing the planetary boundary for carbon dioxide on land and in the oceans.
Land- flooding and extreme weather patterns, mass extinction.
Ocean- Acidification, mass extinction
What does “nitrogen is an inert gas” mean?
Nitrogen is unreactive
What is the process of nitrogen fixation?
Any natural or industrial process that causes free nitrogen (N2) to combine chemically with other elements to form more-reactive nitrogen compounds such as ammonia, nitrates, or nitrites
Name the nitrogen- fixing bacteria that are free-living in soil.
Azotobacter
How do they maintain the aerobic conditions needed for nitrogen fixation?
Ploughing soil and draining fields
Name the nitrogen-fixing bacteria that live in legume root nodules
Rhizobium.
Why is the relationship between Rhizobium and legume root nodules symbiotic?
Both organisms benefit
What is the function of Leghaemoglobin?
Molecule that Rhizobium use to obtain oxygen
What do fungi and bacteria convert amino acids and urea to in the process of decomposition?
Ammonia
Describe both steps in nitrification, naming the bacteria that do each step.
Ammonium to Nitrites by Nitrosomonas and Nitrites to Nitrates by Nitrobacter.
Is nitrification an aerobic or anaerobic process?
Aerobic
What is the impact of waterlogging on nitrification?
Decrease nitrification
What is denitrification?
Conversion of nitrogen containing compounds into atmospheric nitrogen.
Under what conditions does denitrification take place?
Anaerobic
What is the impact of water logging on nitrate levels of soil?
Oxygen levels of soil are reduced
How would ploughing and draining fields increase nitrate levels in soil?
Creates aerobic conditions allowing nitrifying bacteria to survive
Why are fertilisers applied to farmland?
Increase crop yield
What are the benefits and drawbacks of inorganic fertilisers?
You can carefully manage the amount of each nutrient and it’s concentration- require a lot of energy to synthesise
What are the benefits and drawbacks of organic fertilisers?
Can’t control the specific nutrient concentrations but are natural and require no extra energy input to obtain
What is leaching?
Excess water removes water- soluble nutrients out of the soil, by runoff or drainage.
Describe the process of Eutrophication
- Increased nitrates in the water increase the growth of algae and plants.
- The algae from a bloom over the water surface, preventing sunlight reaching other water plants
- These plants die because unable to carry out photosynthesis without light.
- Microbes such as bacteria increase in number as they feed off the dead plants, using and reducing the oxygen content in the water during respiration as they do so.
- The low oxygen levels can cause aquatic insects and fish to suffocate, eventually the lake may be left completely lifeless.
Wildflowers grow on nutrient poor soils, how does the use of fertilisers impact species diversity?
Wildflowers cannot survive if fertilisers are applied and therefore species diversity is reduced.
