Enviromental Interactions Flashcards
Define ecology
Study of inter-relationships between organism and their environment
Define ecosystem
Dynamic systems made up of a community and all the non- living factors of its environment
Define community
All the populations of different species living and interacting in a particular place at the same time
Define population
Amount of one species that occupy a particular place at a particular time
Difference between abiotic and biotic factor
Biotic - living
Abiotic - non living
Factors that affect organisms
Define biomass
Total mass of organisms,
(refers to living organisms - fresh biomass)
What are pyramids of number
Represent the number of organisms in each trophic level in a food chain - irrespective of their mass
What are pyramids of biomass
Shows total mass of organisms in each trophic level - irrespective of their number
Method for random sampling
- divide area into grid using tape measure
- use random number generator to get coordinates
- at each coordinate, place quadrant and count no. Of organisms in each quadrant
- repeat process 20 times of more -> sample size is representative of whole area
- work out average no. Of organisms per quadrant and divide size of quadrant and multiply by size of whole area
Equation to work out density of organism in an area
Population density = mean plants per quadrat / area per quadrat
What does random sampling do
Eliminates bias
Examples of biotic factors
Prey/predators
Human activity
Disease
Competition for resources
Examples of abiotic factors
mineral ions in soil (eg.Clay vs chalk), climate (temperature, water availability, light intensity)
Define habitat
Place where an organism lives
(is characterised by physical conditions and other types of organisms present)
Order of trophic levels
Producer -> primary consumer -> secondary consumer ->tertiary consumer -> quaternary consumer
What can the animal at the end of the food chain be called
Apex predator or top carnivore
Advantage of food webs compared to food chains
More accurate way of showing the feeding relationships between organisms
Disadvantage of food webs
Don’t show how many organisms are involved in food web, and the role of de composers
What does CORMS stand for
Change - changing IV
Organism - same species/sex/age/mass
Repeats - at least 3 repeats (20 or more for quadrat)
Measure - measure DV - what and how
Same - CV
What is sampling used for
To estimate the population size in a given area
IV,DV and CV of how light affects rate of photosynthesis
IV - light intensity (dist between lamp and plant)
DV - no. Of oxygen bubbles produced at diff light intensitys (volume of oxygen)
CV- mass, species of plant, no. Of leaves, volume of water, CO2 conc,
Test for starch
Add Iodine to sample
Orange -> blue/ black - positive
Method for testing leaves for starch
- Bunsen -> boil beaker of water
- leaf in boiling water
- Bunsen off
- leaf in test tube with ethanol
- test tube in boiling water
- wash leaf in warm water
- leaf on white tile + iodine
- black brown -> positive
Why do we
- put leaf in boiling water
- put leaf in ethanol
- wash leaf in warm water
- add iodine to leaf
- stops any further photosynthesis + removes wax
- removes chlorophyll ( green)
- softens leaf
- able to see in starch is in leaf
