Populations Flashcards
Define Biotic Potential
The reproductive rate of a population under optimum environmental conditions with unlimited food resources
Define Environmental resistance
The restriction by the environment on the population reaching its maximum growth potential and biotic potential.
Carrying Capacity
The maximum number of a population that an ecosystem can support
What is competition between different organisms
When different organisms are competing for the same resource.
What is intraspecific
among members of the same species
What is interspecific
Among members of different species
How to determine the change in size of a population
Birth - deaths + immigration - emigration.
What is r- selected species
-grow very quickly
-increase population very quickly when conditions are ideal
-boom and bust
-emphasis on reproduction and colonisation of new areas rather than survival
eg bacteria and annual plants
What are k- selected species
-stable
-population size remains close or at carrying capacity
-emphasis on survival and dominance rather than expanding population
-eg humans and large mammals
What is a parasite
A parasite can be defined as an organism that lives in or on another organism (host) benefiting from it and causing it harm over an extended period of time
How do parasites differe from predator-prey
-parasite lives in or on host
-parasite causes harm to the host over an extended period of time
-parasite usually smaller than host
-parasite seldom kills the host
What is mutualism
Both partners benefit
What is a pest species
A species that damages a valuable crop species, causing economic damage.
Biological control
deliberately introducing an organism that will target and cause harm to the pest, eg a predator, competitor parasite or pathogenic organism
Advantages of biological control
-no chemical damage to the environment with the risk of significant ecological harm and bioaccumulation in food chains
-targets only the pest species
-development of resistance unlikely
-pest resurgence is unlikely
-if successful, it needs little additional action and saves money on continued use of pesticides
Disadvantages
-pest is unlikely to be totally eliminated
-will only work if target species can adapt well and thrive in the ecosystem
