Populations And Sustainability Flashcards
(47 cards)
Define carrying capacity
Max populations size that can be maintained in a habitat over a period of time
Describe a K-strategist curve
1) lag phase= slow growth, few organisms, acclimatising to habitat, rate of reproduction low
2) log phase= rapid growth, resources are plentiful and conditions favourable, rapid population increase
Exponential growth
3) stationary phase= a stable state population size, reached carrying capacity, habitat cannot support a larger population
May fluctuate
What are r-strategists
Boom or bust, extremely high reproductive rate and population growth rate before limiting factor take effect.
Small short lived species (pioneer)
Similar to stationary phase except there is a death phase after
Define limiting factors
Factor that prevents further growth of a population and in some cases cause it to decline
Name 3 abiotic factors
Temperature
pH
Light intensity
Name 3 biotic factors
Competition
Predation
Disease
Define immigration
Movement of individual organisms into a particular area
Define emigration
Movement of individual organisms away from a particular area
How can an introduced species affect other species living in the area
They might be predators
They might stop birds breeding and that reduces their offspring
Means there are less new breeders for the next year
How could a species introduced to an island dramatically increase in number after introduction
Plenty of food and space
There is no predators
Fill a vacant niche
Cannot emigrate
What are density independent factors
Affect populations of all sizes in the same way, examples are natural disasters and fires
What is competition
When organisms compete for limited resources like: light, mates, food, water, minerals and space
What are the two types of competition
Infraspecific
Interspecific
What is interspecific competition
Competition between organisms of different species 😁
What is interspecific competition
Competition between organisms of the same species
Describe interspecific competition
There will be less food and less energy for growth and reproduction
What is competitive exclusion principle
Give an example
Two species are competing for the same food source and the one that uses the resources more effectively will ultimately eliminate the offer
Red and grey squirrels, red squirrel are limited in what they can eat, grey squirrels can eat loads but outcompete the reds by eating all there limited food
Explain the exponential growth in a K strategist curve
Resources are plentiful so population increases in size
Describe the predator prey model
Predators eat prey Prey population decreases Predators compete for limited prey Predator population decreases Fewer prey eaten Prey population increases More food for predators so population increases
How is the predator prey cycle different in the lab rather than the field
The curve in the field has fewer limiting factors
No studies have been done in more diverse environment
Summarise the effect predators may have on the population size of prey
Prey numbers rise and fall- oscillate
Predators help to keep the prey numbers stable
Predation is density- dependent
What are density dependent factors
Factors are dependent on population size
Define conservation
Management of ecosystems sustainably to protect biodiversity
Occurs through, maintaining diversity between species, maintaining habitats and genetic diversity
Define reclamation
Process of restoring ecosystems that have been destroyed
