Ecosystems and the Relationships in Them!

Today’s Objectives

• Explain the interaction of biotic and abiotic factors in an ecosystem– Explain why ecosystems with similar characteristics can

exist in different geographical locations– Identify biotic and abiotic factors in a given scenario or

diagram– Describe the relationships between abiotic and biotic

elements within an ecosystem, including:• Air, water, soil, light, temperature (abiotic)• Bacteria, plants, animals (biotic)

Ecosystems and the Relationships in Them!

Ecosystem: a region that has abiotic components (oxygen, water, nutrients, light and soil) that interact with biotic components (plants, animals, and micro-organisms). They are contained within Biomes

How big are they??• Ecosystems can be very large – eg. Coastal

Douglas Fir ecosystem• Or… very small – eg. A small

tide pool or rotting log

• Within Ecosystems are habitats• A habitat is a place in which an organism lives

The Structure So Far

Biomes

Ecosystems

Habitats

Made up of

Made up of

Interactions within an Ecosystem - Biotic with Abiotic

• The abiotic factors in an ecosystem are just as important as the biotic factors because they all interact with each other.

• Plants and animals (biotic) cannot survive without oxygen, water, and nutrients (abiotic)

• Eg. Plants need light for Photosynthesis – a process that converts light energy into chemical energy for the plant.

Example #1: Abiotic Factor = Sunlight in Deep water…

abiotic factor = limited sunlight

biotic factor = little if any plant growth because without sunlight can’t carry on photosynthesis

Example #2: Abiotic Factor = Sunlight in Rainforest Canopy…

abiotic factor = sunlight

Biotic factor = top of canopy gets lots of sunlight = lots of plant growth

Biotic factor = lower canopy gets less sunlight = only plants that can grow with less sun

Abiotic factor = Soil…• Soil provides nutrients for plants

and a home for many small organisms (insects, bacteria, etc…)

• Did you know… a square meter of soil can contain as many as 1000 species of invertebrate (no backbone) species!!

Interactions within an Ecosystem - Biotic with Biotic

• Biotic things will also interact with each other – animals with plants, plants with plant, and animals with animals, microbes with plants, etc…

• But first we have to understand the interactions and what the groups are called that interact.

The pattern of Interaction

• Species – a Group of closely related organisms that can reproduce with each other.

• Eg. Bears (Grizzly species vs. Black species vs. Polar bear species)

• Population – all members of a particular species within an Ecosystem

• Eg. All Polar bears in Canadian arctic• Community – all the populations of different

species within an ecosystem• Eg. All different species in the Canadian arctic

Energy Flow in Ecosystems

• The flow of energy from interactions within an ecosystem is called energy flow.

• Eg. When a deer eats grass, the energy that was in the grass transfers or “flows” to the deer

• The Grass is a producer – produces food in the form of carbohydrates during photosynthesis

• The deer is a consumer – consumes or feeds on the food/energy of something else.

• When the deer dies, it’s energy is absorbed by decomposers – organisms that break down dead organisms and organic waste and turn it into useable nutrients (snails, fungus).

• The energy is now recycled from the decomposers back to the producers(plants) that use the nutrients to grow.

• And so continues the cycle of energy flow!

See the Pattern??

• Based on this picture…What do you think Herbivore, omnivore, detritivore and carnivore mean??

Types of Consumers• Herbivore – consumers of

plants (grasshopper, deer, sheep)

• Omnivore – consumer of plants and animals (bears, pigs)

• Carnivore – animal (meat) eaters only (wolves, spiders)

• Detritivore – eats dead organisms (plant/animal) and animal waste (pill bugs, snails, bacteria)

So how do we easily show Energy Flow?

• Food webs/chains/pyramids are a quick portrait of the feeding patterns and energy transfer within an Ecosystem.

• Each step in the food chain is called a Trophic Level

• So producers are at the start of the food chain so they are the FIRST Trophic level

Trophic Levels

Primary producers – produce the initial food

Primary consumers – eat primary producers

Secondary consumers – eat primary consumers

Tertiary consumers – eat primary AND secondary consumers

Food Chain

Food Web

Food

Pyra

mid