Topic 10 Flashcards
Define ecosystem
A network of habitats and communities with organisms interacting with each other and the abiotic and biotic factors in the environment around them
What are abiotic and biotic factors
Abiotic is non living component of ecosystem biotic is living
Define habitat
A place where an organism lives
Define community
All the populations of a different species living in a habitat at any one time
Define tropic level
the place an organism is positioned in the food web/chain
What is the biosphere
Global sum of all ecosystems representing all life on earth
Define a biome + examples
Large ecological area repressing a broad community type. tundra, grassland, desert, tropical rainforest
Pyramid of numbers advantages+disadvantages
Shows the structure of the ecosystem
Can just be counted
Doesn’t account for size or biomass of organisms
Doesnt reflect energy flow or efficiency between levels
Pyramid of biomass advantages + disadvantages
Total dry mass of all organisms at each trophic level
Doesn’t reflect rapid change in population
Very difficult to measure
Pyramid of energy advantages + disadvantages
Represents energy flow through each trophic level over a specific period of time
Difficult to collect data
Assumes a linear food chain which isnt true
Ways energy is lost through food chain
Respiration
Incomplete consumption
Undigested material
Excretion
Heat loss
Define abundance
Proportion of individuals of a species compared to the total number of individuals of all species
Define distribution and its 3 patterns
The way individuals of a species are spread out in a habitat. Clumped, uniform, random
What is a quadrat and how do you use it
square frame for both abundance and distribution. Done random or systeatically
Percentage cover or individual count
Limitations of a quadrat
Sampling Bias:
Results depend on the random or systematic placement of quadrats, which may not fully represent the whole area.
Scale Issues:
Quadrat size may not be appropriate for larger organisms or very small ones, potentially leading to underestimation or overestimation.
Subjectivity in Percentage Cover:
Estimating percentage cover can be subjective and vary between observers.
Limited to Immobile or Slow-moving Species:
Quadrats are not suitable for fast-moving organisms like animals.
What is the ACFORD scale
Subjective method to measure abundance.
Subjective so it sucks
What is a transect
Line transect measures presence of organism
Belt trance measures count, percentage cover or density
Ecological techniques other than transect, quadrat
Light trap. Mark Recapture. Tree beating, roadkill counts
Define GPP and what is it measured in
gross primary productivity. the rate at which the sun catalyses the production of new plant material gm^-2yr^-1
Define NPP and how to find it
Net primary productivity
NPP = GPP - R
Usable energy stored by the plant.
Nitrogen Cycle
Nitrogen fixing - Atmospheric N2 converted to ammonium or nitrates by nitrogen fixing bacteria or lightning
Ammonification - Decomposers break down organic matter into ammonium
Nitrification - Nitrifying bacteria convert ammonium into nitrites and then nitrates for plant
Assimilation - Plants absorb them to synthesis proteins + nucleic acids
Denitrification - Denitrifying bacteria converts nitrates back into atmospheric N2
Where does nitrogen fixation occur
Leguminous plant root nodules.
Bacteria provide nitrates and plant provides with carbohydrates
Carbon cycle
CO2 in atmosphere
Water absorbs
Plant and algae absorb CO2 and then are eaten by plants
CO2 released by respiring
Decomposers release CH4 or CO2
Carbon is stored in fossil fuels
Those are burnt and released
Define colonisation
The process by which organisms establish themselves in a previously uninhabited or disturbed area
Define succession
The gradual process of change in the species composition and structure of an ecosystem over time
Define climax community
The final, stable and self-sustaining community of organisms that develops at the end of ecological succession
Define climatic climax community
A climax community that is determined by the local climate
Define a phagioclimax
A community that has been altered or disrupted, preventing it from reaching natural climax community
What is primary succession
Completely destroyed community. Pioneer species are lichens and mosses.
What is secondary succession
Disturbed area but pioneer is grasses that are there
Abiotic factor that affect population
Light intensity, temperature, water availability, soil pH and mineral content, oxygen availability, CO2 levels, wind and air currents, salinity, natural disasters,
What is an edaphic factor
A soil related abiotic factor that influences the growth and distribution of plants
Biotic factors that affect a population
Predation, finding a mate, territory, parasitism, disease, intraspecific and interspecific competition
Intra vs inter specific competition
Intra is in the same species
Inter is different
Main difference is inter doesnt compete for mates
What is CITES and its limitations
International agreement to protect animals and their trade. Has achieved lots of protection but has no legal obligations and countries don’t have to sign up, It is only about trade agreements not conservation
