Download Ecosystems and their interactions

Ecosystems
• The Biosphere the sum of all the ecosystems on earth
• An ecosystem is a self-sustaining association of plants, animals, and the physical
environment in which they live
• An ecosystem is made up of many parts.
 Abiotic factors include air, water, soil, nutrients, and light.
 Biotic factors include plants, animals, and micro-organisms.
 A habitat is where an organism
lives.
The habitat of the red fox often includes the
edges of forests or marshlands.
(c) McGraw Hill Ryerson 2007
Abiotic Interactions in Ecosystems
•
The abiotic components are what allow the biotic components to
survive in an ecosystem.
 Abiotic factors include oxygen, water, nutrients, light and soil.
 Oxygen
 Water
 Nutrients
.
 Light is required for photosynthesis,
 Soil not only contains water and nutrients
but also is home to many plants and animals.
Earthworms in soil
See pages 37 - 38
(c) McGraw Hill Ryerson 2007
Biotic Interactions in Ecosystems
• A community = all the organisms that interact within an
ecosystem.
 A species refers to all of the organisms within an ecosystem that have
the same structure and that can reproduce with each other.
 A population refers to all of the members of a certain species within an
ecosystem.
(c) McGraw Hill Ryerson 2007
Symbiotic relationships are the interactions between
two different species that live together in a close
association.
 Commensalism – one species benefits, one is not affected
 Example: the barnacles on a whale
(c) McGraw Hill Ryerson 2007
Mutualism
 Mutualism – both species benefit
 Example: a bee gathering nectar from a flower
(c) McGraw Hill Ryerson 2007
Parasitism
 Parasitism – one species benefits, the other is harmed
 Example: hookworm living in dogs
(c) McGraw Hill Ryerson 2007
Predation
• Predation-one organism (Predator) eats all or parts of another
organism (Prey)
 Predators have adaptations to help them catch their prey.
 Prey have adaptations to help avoid predators.
 Examples of adaptations include spines and shells, camouflage and
mimicry.
 The numbers of predators and prey influence each other.
.
(c) McGraw Hill Ryerson 2007
Energy Flow in the Ecosystem
•
Within an organism’s niche, the organism interacts with the ecosystem by:
1. Obtaining food from the ecosystem
2. Contributing energy to the ecosystem
 Primary Producers are plants that produce carbohydrates from carbon
dioxide, water, and the Sun’s energy.
 Consumers get their energy by feeding on producers or other
consumers.
Primary get energy from producers (Herbivores)
Secondary get energy from primary consumers (Carnivores)
Tertiary get energy from secondary consumers (top Carnivores)
 Decomposers such as bacteria and fungi change wastes and dead organisms
into nutrients through the process of biodegradation
 Detrivores which are small insects, earthworms, bacteria or fungi that get
nutrients from dead plants, animals or their wastes
(c) McGraw Hill Ryerson 2007
Energy Flow and Energy Loss in Ecosystems:
Food Chains
• Scientists use different methods to represent energy moving
through ecosystems.
 Food chains
 Food webs
 Food pyramids
Examples of terrestrial and aquatic
food chains
• Food chains show the flow of
energy in an ecosystem.
• Each step in a food chain is a
trophic level




Producers = 1st trophic level
Primary consumers = 2nd trophic level
Secondary consumers = 3rd trophic level
Tertiary consumers = 4th trophic level
(c) McGraw Hill Ryerson 2007
Energy Flow and Energy Loss in Ecosystems:
Food Webs
• Most organisms are part of many food chains.




Food webs represent interconnected food chains.
Food webs are models of the feeding relationships in an ecosystem.
Arrows in a food web represent the flow of energy and nutrients.
Following the arrows leads to the top carnivore(s).
This food web is an example
from a terrestrial ecosystem in BC
(c) McGraw Hill Ryerson 2007
Energy Flow and Energy Loss in Ecosystems:
Food Pyramids (continued)
• Food pyramids are also known as ecological pyramids.
 Ecological pyramids may show biomass, population, or energy numbers.
 The amount of life an ecosystem can contain is based on the bottom level of
the ecological pyramid, where producers capture energy from the Sun.
 Each level in the energy pyramid = a loss of 90 percent of total energy
available.
 Lower trophic levels have much
larger populations than upper levels.
 This shows the importance of
maintaining large, biodiverse
populations at the lowest levels
of the food pyramid.
(c) McGraw Hill Ryerson 2007