populations Flashcards
Define population
Population is the number of organisms of the same species that live in a particular geographical area at the same time
Why can populations not be sustained indefinitely?
Limiting factors
Explain the population growth curve phases
1) Slow growth: Small numbers reproduce to increase population, birth rate > death rate
2) Rapid growth: Total population will grow exponentially (Double at regular intervals) due to no constraints
3) Stable growth: Growth is restrained by limiting factor, Birth rate = Death rate
What is the carrying capacity?
Maximum population size that can be permanently supported by a habitat
What are the differences between a K and R strategist?
K strategist : Low reproductive rate , slow development but a long life span and large body mass. The limiting factor will exert more as population nears carrying capacity
R strategist: High reproductive rate, fast development, short life span and small body mass
Population size will go over carrying capacity
What is the exponential growth curve?
The population size will double each fixed position.
Usually occurs during exponential growth
Represented by a logarithmic scale (Straight line)
Describe the basic predator and prey interaction
1: Increase in prey population provides more food for predators and more predators can survive, predator population increase
2: More predators= Greater decline in prey
3: Larger predator population can not be sustained by declining prey numbers, predator population falls
4: Prey population will increase
What is the difference between intraspecific and interspecific competition?
Intraspecific: Competition between members of the same species
Interspecific: Competition between members of different species
What are competitive exclusion principles?
The idea that there are no two species that can occupy the same niche, the one that is more adapted is more likely to outcompete the less adapted one
Describe intraspecific competition
1) Plentiful resource, all organisms can survive and reproduce and increase population size
2) Resources are now limited, population will decrease
3) Less organisms, more can survive, reproduce and increase population
What is the difference between conservation and preservation?
Conservation: Maintenance of biodiversity through human activity and management
Preservation: Protection of an area by the restriction of human interference
Why is conservation important?
For social, ethical and economical implications
What are the aims of sustainability?
+ Preserve the environment
+ Ensure there are resources for the future
+ Allow economically less developed countries to develop
How is small scale timer production made sustainable?
Coppicing: Trees are cut close to the base so that new shoots will form and these can be harvested repeatedly rather than cutting down the whole tree
Polarding: Same as coppicing but higher up to avoid deer and other animals eating it
How can you make large scale timber production sustainable ?
Consider several other factors when removing large masses of trees such as replacing trees, planting trees at a distance to reduce competition etc..
