Populations In Ecosystems Flashcards
Equation for population growth
Pop growth= (births + immigration ) - ( deaths + emigration
Percentage Population growth rate equation
% pop growth rate = population change during the period/ population at the start of the period x100
Mark release recapture equation
Estimated population size= total number of individuals in the 1st sample x total number of individuals in the 2nd sample / number of marked individuals recaptured
Assumptions of mark release recapture
No births or deaths or migration - pop size is constant
There’s enough time for the organisms to distribute themselves (no assumption they redistribute uniformly tho)
The mark isn’t rubbed off
(Size of the total area isn’t required )
Physiological Adaptations of pioneer species
Ability to photosynthesise
Resistant to high light intensity
Ability to fix nitrogen from the atmosphere
Rapid germination of seeds
Interspecific and infraspecific competition differance
Inter = diff species compete for same resource
Intra= same species compete for a mate and same resources
Carrying capacity
Max population an ecosystem can support
Niche
Organisms role within an ecosystem .each species occupies its own one
Ecosystem
A community and the non living components of an environment
Community
All populations of different species in the same area at the same time
When investigating populations what must you do with calculations
Round up or down as talking about numbers of animals
Less harsh abiotic factors =
Larger range of species and each species will have a larger pop size
Why will the prey population peak at a higher point
The predators are further along the food chain so whatever there eating contains less energy so to gain enough energy from there food they have to eat more numbers of prey compared to the predator population
Niche separation
If occupy different niches
Types of line transects
Interrupted belt transect and a belt transect (quadrant at every position on line)
3 ways of collecting data in investigating population sizes
Local frequency
Density
Percentage cover
Local frequency
Count the number of squares with the species present
100 squares - ?/100=?% show as percentage
Repeat x30 and calculate a mean % and this = estimate for entire field
Density
Number of species present in a given area
Work out how many quadrants fit in field (divide area by size of quadrat)
X this by number of individuals in the quadrat = number of species in entire field
Percentage cover
Estimate of how many full squares out of 100 are completely covered by species
Ecology
The study of the inter relationships between organisms and their environment
Micro habitats
Within each habitat there are smaller units with their own microclimate
Competitive exclusion principle
No 2 species occupy the same niche, some may appear similar but their nesting habits or aspects of their behaviour will be different or they have have different levels of tolerance to pollutants or shortage of o2
Limiting factors on populations growth
Availability of food, light, water, oxygen and shelter
And the accumulation of toxic waste, disease and predators
