Topic 6 - Populations And Communities Flashcards
What is a population
A group of organisms of the same species living in a particular area
What are the 4 distinct phases of Population growth
Lag phase
Exponential phase
Stationary phase
Decline phase
What is the Lag Phase in population growth
This is a strange when nutrient assimilation takes place involving the bacteria activating genes and producing the appropriate enzymes to metabolise a particular food substrate
What is the exponential phase in population growth
This is when there is no restriction of growth and bacteria divides exponentially
What is the stationary phase in population growth
This is the stage when food supplies may begin to become limiting so the number of new individuals produced falls
What is the decline phase in population growth
This is when the death rate exceeds the birth rate and the population declines, possibly due to accumulation of waste or nutrient supply running out
What is the biotic potential
The maximum rate of growth as seen in the exponential phase
What is environmental resistance
The restriction by the environment on the population reaching its maximum growth rate and its biotic potential
What are abiotic factors
Factors in the chemical or physical environment and are losselt referred to as non-living
What are biotic factors
The effects of other organisms whether the same or other species
What is the carrying capacity
The maximum number of a population that the ecosystem can support
What are renewable resources
The nutrients that were there at the start of the investigation were not replaced
What is intraspecific competition
Competition between members of the same species
What is interspecific competition
Competition between members of a different species
What are some commons features of a predator-prey graph
The predators peaks and troughs lag behind the preys peaks and troughs
The length of the predator cycle is usually similar to the length of the prey cycle
The number of predators is normally significantly lower than the number of prey individuals
What are r-selected species
Opportunistic Individuals or groups that tend to grow very quickly and increase in population when conditions are ideal
What are k-selected species
Stable populations and the population size usually remains at or close to the carrying capacity of the species
What are some features of an r-selected species
Small body size
Short lived
Reproduce rapidly
Little parental care
Population size variable
Low competitive ability
Not specialised
Inhabit unstable habitats
What are some features of K-selected species
Large body size
Long life cycle
Few offspring
Large amount of parental care
Low dispersal ability
High competitive ability
Highly specialised
Occur in stable habitats
What is a parasite
An organism that lives in or on another organism benefiting from jr and causing it harm over an extended period of time
How do Parasites differ from predators
The parasite lives in or on the host
The parasite causes harm to the host over an extended period of time
The parasite is usually smaller than the host
The parasite seldom kills the host
What is mutualism, and give an example
The interaction where both partners benefits, Lichens between Fungi and green algae
What is a pest species
A species that damages a valuable/ commercial crop species, causing economic damage
What does biological control involve
Deliberately introducing an organism that will target and cause harm to a pest
