Transcript SNC1D Ecology lecture 1

Sustainable Ecosystems
Concept of Sustainability
• Ecosystems: all the interacting parts of
a biological community and its
environment
• Sustainable Ecosystem: An ecosystem
that is capable of withstanding pressure
and giving support to a variety of
organisms
The Case of Easter Island
• Is thought to be a once thriving island
• People built statues and lived in forested area
• People cut down trees to grow crops, to burn
as a heat source, until there were no more
trees
• This lead to erosion, loss of plants as a food
source, no extra materials to make houses,
boats
• The island could no longer support the
human population and society began to die
off
• Only the statues remain
Parts of an Ecosystem
• Biotic Factors: living parts such as
plants, animals, and microorganisms
• Abiotic Factors: non-living parts such as
water, oxygen, light levels, nutrients
Biotic Interaction
•
The interaction between members of two different species that live
together in a close association. You may not see any interaction
from the surface, the sea anemone and the clown fish. The clown
fish eats animals that are attracted to the sea anemone and the
fecal matter from the fish feeds the sea anemone
• There are three main types of symbiotic relationships:
1. Mutualism- both organisms benefit from the relationship
2. Commensalism- one organism benefits while the other is unaffected
3. Parasitism- one organism benefits at the cost of the host
Predation
• When one organism consumes another
organism for food
• The consumed organism is called prey eaten
by the predator
• This lady bug is the predator for aphids a bug
that destroys many crops.
Competition
• Occurs when two or more organisms
compete for the same resource such as food
in the same location at the same time.
• Dandelions compete with the grass for same
resources, water, nutrients and light
Abiotic Characteristics
• Key factors are: their importance and role on
ecosystems
• Water
– cells are mostly made up of water, wastes are disposed of
with water, many animals and plants live in water
– Water availability, desertification, water quality and
pollution
• Oxygen
– Essential for cell processes, animals breath it where it is
absorbed into blood to the cells. Aquatic animals get
oxygen through water
– Human activities can lower oxygen levels in water
depleting fish populations, pollution
Abiotic continued
• Light
– Photosynthesis requires light. Plants and algae need light
to undergo this process. All energy for ecosystems
comes from light energy converted to other forms of
energy
– Amount of light is affected by ecosystems, forest trees
block light from plants underneath, sediment in water
blocks light for algae
• Nutrients
– All organisms need nutrients, key ones are nitrogen and
phosphorous
– Human activities can alter nutrient levels, clear cutting,
fertilizer run off etc.
• Soil
– Provides structure for growth in plants, provides nutrients to
plants
– Top soil contains most of nutrients can be washed away from
heavy rains
Homework
• Pg 9 # 1-4
• Pg 20 # 1-3