population in an ecosystem Flashcards
ecology
the study of inter-reloationships between species and the environment
biotic
living factors of the environment
aboitic
non-living factors of the environment
what is a ecosystem
Ecosystems are dynamic systems made up of a community and all
the non-living factors of its environment.
what are the two main parts to an ecosystem
the flow of energy through the system
• the cycling of elements within the system.
population
all individuals of the same species that can interbreed to produce fertile young in the same habitat at the same time
carrying capacity.
when a ecosystem supports a certain size of a population.
what can affect population size
the effect of abiotic factors
intraspecific and interspecific competition
predation.
community
all populations of the different species living and interacting in same habitat at the same time
habitat
A habitat is the place where an organism normally lives and is characterised by physical conditions and the other types of organisms
microhabitat
smaller units within habitats that have their own microclimate
competitive exclusion principle
states that two species that compete for the exact same resources cannot stably coexist
niche
it describes how a species fits into the habitat
it is where an organism lives and what it does there.
It includes all the biotic and abiotic conditions which an organism is adapted
examples of limiting factors to bacteria population
biotic
• The population becomes so large that the bacteria at the surface
prevent light reaching chose at deeper levels.
Other species are introduced into the pond
examples of limiting factors to bacteria population
abiotic
Winter brings much lower temperatures and lower light intensity of shorter duration.
Mineral ions are consumed as the population becomes larger.
temperature
and cold-blooded animals, as temperatures rail below the optimum,
the enzymes work more slowly and so their metabolic rate is reduced.
Populations therefore have a smaller carrying capacity.
At temperatures above the optimum, the enzymes work less
efficiently because they gradually undergo denaturation. Again
the population’s carrying capacity is reduced.
temperature in warm blooded animals
temperature of the external environment gets rrom their optimum
temperature, the more energy these organisms expend in trying to
maintain their normal body temperature. This leaves less energy
for individual growth and so they mature more slowly and their
reproductive rate slows. The carrying capacity of the population is
therefore reduced.
light
The rate or photosynthesis increases as
light intensity increases. The greater the rate or photosynthesis,
the faster plants grow and the more spores or seeds they produce.
Their carrying capacity is therefore potentially greater. In tum, the
carrying capacity of animals that feed on plants is potentially larger.
ph
This affects the action of enzymes.
Each enzyme has an
optimum pH at which it operates most effectively. A population of
organisms is larger where the appropriate ph exists and smaller,
or non-existent, where the pH is different from the optimum.
water
Where water is scarce, populations are small and consist only of species that are well adapted to living in dry conditions.
humidity
Humidity affects the transpiration rates in plants and the evaporation of water from the bodies of animals.
dry air conditions, the populations or species adapted to tolerate low humidity will be larger than those with no such adaptations.
population change equation growth rate
population change during the period/ population at the start of the period
x 100
population growth
= (births+ immigration ) - (deaths + emigration )
Intraspecific competition00.
is when individuals of the same species
compete with one another for resources such as food, water. breeding sites, etc.
The greater the availability, the larger the
population. The lower the availability, the smaller the population.
Availability of resources also affects the degree of competition between
individuals which results in a smaller population.
