Download Document

8.L.3.1 Explain how factors such as food, water, shelter and
space affect populations in an ecosystem
Ecosystem- includes all of the living things (plants,
animals and organisms) in a given area, interacting with
each other, and also with their non-living environments
(weather, earth, sun, soil, climate, atmosphere).
Ecology- the branch of biology dealing with the relations
and interactions between organisms and their environment
Biodiversity – the degree of variation of life. Variety of
organisms present in different ecosystems.
Plants and animals need air, water, light (plants only),
space, food and shelter…
these things can be found in their environment.
 Population - all the individuals of a given species in a
specific area or region at a certain time.
 Community - refers to all the populations in a specific
area or region at a certain time.
 Environment – the surroundings or conditions in which
an organism operates.
 Habitat – the natural surroundings or environment in
which an organism lives
Biotic and abiotic factors make up
an ecosystem…
 Biotic Factor – are all the living organisms within an
ecosystem
 Abiotic Factor – are all of the non-living things in an
ecosystem (ex: pH, sunlight, turbidity, available
nutrients, wind, etc.)
What is a niche?
 Niche - the status of an organism within its
environment and community (affecting its survival as a
species). It includes:
 The role a species has in its environment
 Its interactions with the biotic and abiotic factors of its
environment
Coexistence and Competition
 Competition – occurs when a resource that is
essential to growth and reproduction occurs in short
supply. It is an interaction that has a mutually negative
effect on the participants.
 Coexistence – occurs when populations of several
species that utilize the same limiting resources manage
to persist within the same area.
Population Density
 It is a measure of the number of organisms that make
up a population in a defined area.
 What is its significance?
 Ecosystems function best when they have the correct
number of organisms making up a population to utilize the
resources available.
 Ideal number of a population = carrying capacity
 Population density = Population / Total land area
Limiting Factors
 Environmental factors that limit population sizes in a
particular ecosystem.
 Examples:





Food/nutrients
Temperature
Water
Natural Resources
Predation
Density Dependent Factors
 Any factor limiting the size of a population whose effect
is dependent on the number of individuals in the
population.
 Ex: Disease having a greater effect in limiting the growth
of a large population, since overcrowding facilitates its
spread.
Density Independent Factors
 Any factor limiting the size of a population whose effect
is not dependent on the number of individuals in the
population.
 Ex: Earthquake, impacts all members of a population
regardless of whether the population is large or small.
8.L.3.2 Summarize the relationship among producers, consumers and decomposers, including the positive and
negative consequences of such interactions including:
Coexistence and cooperation
Competition
Parasitism
Mutualism
 Three categorizes of the food chain:
 Producers
 Consumers
 Decomposers
They are
dependent on
each other!!!
Producers
 Producers get their food and energy from the sun.
 Plants
 They make their food through a process called
photosynthesis
Consumers
 Consumers need to eat their food to get energy
 Animals
 Three Types:
 Carnivores
 Herbivores
 Omnivores
What type are humans?
Consumer:
Carnivores
 Only eat meat (other animals)
Consumer:
Herbivores
 Herbivores only eat plants
Consumer:
Omnivores
 Omnivores eat both meat (animals) and plants
Decomposer
 Decomposers eat dead things and turn them back into
dirt, or soil.
 Ex: Mushrooms, worms, bugs