Ecology

SNC1D

Why Study Ecology?

Sustainability:• The ability to

maintain an ecological balance

Ecology: The study of the interaction of living things with each other and with abiotic factors in their environment.

Abiotic Factors:e.g.

Biotic Factors:e.g.

• Ecology can begin at the level of a single organism

• But organisms do not live in isolation

Ecological LadderBiosphere

BiomeEcosystemCommunityPopulation

SpeciesOrganismIn

crea

sing

com

plex

ity

• Ecosystems rarely have sharp boundaries

• Organisms can move from one ecosystem to another

Ecotone: The transition area between two ecosystems

• Contains members of the community of both ecosystems

Ecotone

Biodiversity: The number and variety of species in an ecosystem

• Ecotones have ______ biodiversity.

• High biodiversity usually indicates a more sustainable ecosystem.

Terms To Define:• 7 terms on the ecological ladder• Herbivore, carnivore, omnivore• Habitat• Sustainable Ecosystem• Natural and Artificial

Ecosystems• Niche

Energy Flow in Ecosystems

The Sun• The source of all energy

• Light• Heat• Evaporation (for precipitation)• Photosynthesis

• _30__% of the total energy is reflected by clouds or Earth’s surface

• _44__% heats atmosphere, surfaces, • __25___% heats and evaporates water• ___1__ % wind• _0.023__% for photosynthesis

Biotic FactorsProducer Consumer

Alternate Name Autotroph Heterotroph

Energy Source

• Make (produce) their own food• From sunlight and basic nutrients (abiotic factors)

• CANNOT make their own food• Must obtain it from autotrophs or other heterotrophs (biotic factors)

Example Plants

HerbivoresOmnivoresCarnivores

Trophic Levels• Categorize living things

(biotic factors) according to how they gain their energy.

1st Trophic Level• Contains organisms that are able to make

their own food from abiotic factors (e.g. soil nutrients, sunlight)

• Organisms in the 1st trophic level are called producers______ or ___autotrophs___

• E.g.

2nd Trophic Level• Contains organisms that feed on producers• Rely DIRECTLY on producers for their source

of energy.• Organisms in the 2nd trophic level are called

herbivores/ primary consumers/ heterotrophs_

• E.g.

3rd Trophic Level• Contains organisms that rely on primary

consumers as their main energy source• But, indirectly, are still dependent on

producers• Organisms in the 3rd trophic level are called

__secondary consumers______________• E.g.

Decomposers• Organisms that feed on detritus

Detritus: Waste from biotic factors, including their dead remain

• Return nutrients (abiotic factors) to the ecosystem

• E.g.

1st Trophic Levels

2nd Trophic Levels

3rd Trophic Levels

4th Trophic Levels

1st Trophic Levels

2nd Trophic Levels

3rd Trophic Levels

4th Trophic Levels

Food Chains• Step-by-step sequence

linking organisms that feed on each other

• Arrows show the flow of energy (“is eaten by”)

• Do not exist in nature• Show simple feeding

relationships

Food Webs

• In reality, each organism has a variety of food sources and is therefore involved in multiple food chains

• These food chains interlock to form a complex food web

Food Web: Representation of the complex feeding relationships in an ecosystem

Energy Flow• Organisms use about 90 % of the

energy they take in to grow and reproduce, leaving just 10% of the energy they receive to pass along to the next trophic level.

grass → grasshopper → frog → snake → hawk

Ecological Pyramids• Are used to organize the information of these

transfers, and the most common are:Type Pyramid of

numbersPyramid of Biomass

Pyramid of Energy

Based on… Population of Organisms

Mass of Organisms

Stored energy in organisms

Drawing