Transcript Earth`s Spheres and Ecosystems

Learning Objectives:
•to understand where organisms are able to survive on Earth
•to understand what an ecosystem is and what factors affect ecosystems.
• to understand the different feeding roles within an ecosystem and how energy is
passed on between organisms
• to understand the different ways of representing organisms in an ecosystempyramids of numbers, biomass and energy
Sustainability
Sustainability refers to the living
in a way that ensures resources
are available for a LONG time.
Sustainable ecosystems are
natural and undisturbed. They
have characteristics that are
constant over long periods of
time.
Unsustainable ecosystems are
unnatural (artificial) and
disturbed. Humans must take
care of these ecosystems for
them to survive (ex. water and
fertilize plants in them)
Ecosystems
An ecosystem consists of the
living organisms in a region,
their interactions with each
other and with their non-living
environment.
Factors affecting ecosystems are:
biotic: living organisms, their
remains, products and wastes.
abiotic: non-living physical
and chemical components.
Earth’s Four Spheres
 Atmosphere: the layer of gases (mainly nitrogen and
oxygen) surrounding the Earth.
 Acts as an insulator, regulating Earth’s surface temperature
 Blocks incoming solar radiation
 Lithosphere: Earth’s outer layer of solid rock.
 Consists of rocks, minerals and soil
 Hydrosphere: all of the water on and below Earth’s surface.
 Water is in solid, liquid and gas form- 97% is found in the
oceans
Earth’s Four Spheres
 Biosphere: the regions within the 3 other spheres where life
exists.
 Very thin compared to Earth’s size.
Levels of Organization
 Organism- a single living
being (plant or animal)
 Population- a group of the
same type of organisms living
in an area
 Community- a number of
different populations of
organisms in an area
 Ecosystem- the community of
organisms and their
interactions with non-living
substances in an area
Habitats
 A habitat is the place where
an organism lives.
 There are two types of
habitats:
Terrestrial – on land
2. Aquatic – in water
1.
 Producers create glucose (chemical energy) from light
energy. They do not need to consume other organisms to get
energy.
 Consumers are organisms which need to eat (consume)
other organisms to get their energy. They cannot perform
photosynthesis.
Feeding Role
Definition
Herbivore
Animal which eats plants or other producers
Ex: Rabbit
Carnivore
Animal which eats other animals
Ex: Lion
Omnivore
Animal which eats both plants and animals
Ex: Bear
Scavenger
Animal which feeds on the remains of another
organism
Ex: Vulture
Decomposer
Organism which feeds on and breaks down dead
plant or animal matter
Ex: Fungus, Earthworms
 A food chain or food web shows how
energy transfers between organisms and
through an ecosystem by giving the order
in which organisms are consumed.
 A food chain consists of a single pathway
of energy transfer.
 The arrows show the direction energy is
moving in from one organism to its
consumer.
Snakes
Toads
Insects
Plants
 A food web contains many different feeding relationships
and energy transfer pathways.
 Trophic level- is the feeding level, or position of the
organism in the food chain.
 Ex: a producer is in the first trophic level
 Consumer level- is the position of the consumer in the
food chain.
 Ex: an herbivore is the primary (first) consumer
 producers do not have a consumer level, because they do not
consume other organisms to get energy.
 The more complex the food web of an ecosystem, the more
stable it is because there is more biodiversity. This means
each organism can get its energy from a number of different
sources. Thus, if one food source disappears, its predators
have other prey to feed on.
Autotroph v. Heterotroph
Produce own
Food
Autotroph
Yes
Food Chain Level Primary
Examples
Heterotroph
No
Secondary and
Tertiary
Plants, algae, some Herbivores,
bacteria
omnivores,
(producers)
carnivores,
scavengers, and
some bacteria
(decomposers)
Food Chain
 a specific pathway by
which materials and
energy move through an
ecosystem
Food Web
 allow for the flow of energy
through organisms
(which all originates
from the sun)
allow for the flow of matter
through organisms
producers (autotrophs—
green plants) capture some of
the sun’s energy; they use
90 % of the sun’s energy
to grow and live; the rest is passed
onto consumers
consumers (heterotrophs) eat green
plants (1o) and other consumers (2o)
a network of interacting
food chains operating in an
ecosystem
it includes more organisms
in an ecosystem than a food chain
shows competition