Population size and ecosystems Flashcards
What is the definition of Population
An interbreeding group of organisms, of a particular species, in a particular location habitat
What is the definition of Community
All of the organisms, of all species, living in one location at one time
What is the definition of ecosystem
A characteristic community of interdependent species and their habitat
What is the definition of Habitat
The location in which an organism lives
What is the definition of Niche
The role of a particular species in its ecosystem, including its microhabitat, feeding and breeding behaviour etc.
what is the definition of ecology
The study of how living organisms interact with each other and their environment
What is the definition of Enviroment
The physical and biological conditions under which an organism lives
What is the definition of biotic
The biological components of an ecosystem
a part of the environment of an organism that is living
what is the definition of abiotic
The non-biological components in an ecosystem
a part of the environment of an organism that is non living
what are ecosystems described as
dynamic as they are constantly changing
due to changes in species composition population sizes Biological cycles successional changes Energy flow Light intensity and mineral availability
What are the 6 things that cause an ecosystem to be dynamic
species composition
population sizes
Biological cycles
successional changes
Energy flow
Light intensity and mineral availability
What are the population numbers dependent on
Birth rate
Death rate
Immigration
Emigration
What circumstance will a population size increase
when
Birth rate + immigration > death rate + emigration
what is the correct term when talking about bacteria’s birthrate
Reproductive rate
What are the 4 phases of the sigmoid population growth curve
lag phase
log phase
stationary phase
Death phase
what is involved during the lag phase
initially population does not increase but then there is a period of slow growth
this phase has a very high metabolic activity
(ENZYME SYNTHESIS)
lag phase in animals like rabbits who reproduce alot
time taken for them to reach sexual maturity so they can properly mate
what is involved in the exponential phase
numbers increase as long as there inst a limiting factor impacting growth
The rate of reproduction however doesn’t stay constant due to ENVIRONMENTAL RESISTANCE
however other factors also impact the growth rate
such as biotic and abiotic factors
what is an environmental resistance
refers to environmental factors
What is are some examples of environmental factors
food available
concentration of waste products becoming toxic
not enough space
What is an example of biotic factors
predation
parsitism
competition
what is an example of abiotic factors
temperature and light intensity
what is involved in the stationary phase
occurs when birthrate = death rate
population has reached its carrying capacity
its not constant fluctuates around carrying capacity
what is the definition of carrying capacity
the maximum number around which a population fluctuates in a given environment
what is involved in the death phase
factors that slow population growth at the end of the lag phase become more significant and population size decreases until the death rate is larger than birthrate
this leads to a decline in in population size
calculations on pg 67
calculations on pg 67
what is the birth rate
the reproductive capacity of a population, the number of new individuals derived from reproduction per unit of time
what is immigration
the movement of individuals into a population of the same species
what is the equilibrium species
species that control their population by competition rather than by reproduction and dispersal
