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