Ecology
GCA General Biology
What is Ecology?
• It is the study of nature.
• Use to be descriptive, but scientists started
asking why?
• Polar bears only in Arctic and not Antarctic.
• Why?
• The migration is impossible.
Australian Rabbit
• http://www.youtube.com/watch?v=pgPhn4tY
xJQ
• Thomas Austin imported 24 rabbits in 1859
• Now the rabbits are being in check by a
combination of viruses.
Role of Ecology
• Study relationships of organisms and their
environment.
• Predict what would happen if something is
changed.
• Recommend steps to change.
• Recommend ways to use natural resources
wisely and without destroying it.
• Deals with crops, pesticides, waste, mining,
and wildlife.
What is an Ecosystem?
• All the living things (biotic) and non-living
(abiotic) factors and their interactions within a
limited area.
• Ecosystems “interact” and depend on each
other.
Ecosystems
Ecosystems
Abiotic Environment
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Radiation (Sun)
Wind and water current
Water
Topography (mountains and valleys)
Fire (controlled burning vs. wildfire)
Tilt and revolution of the earth make seasons
Erosion, volcanoes, earthquakes and floods.
Water Cycle??
Water Cycle
Biotic Community
• All living things in an ecosystem
• Population is all the members of the same
type of living thing occupying the same
geographic area at one time.
Typical Pond Ecosystem
• Populations of lily pads, cattails, mosquitoes,
frogs, turtles, hawks, fish.
• What other Biotic (living) features could be in
this Ecosystem?
Population Information
• Sum or total in an area – How many total
rabbits in Australia?
• Density – How many per square mile?
• Arrangement – They noticed more rabbits by
the fence area.
• Changes over time like birth rate, death rate,
life expectancy.
Key point
• Almost every living thing affects all the other
living things within its ecosystem.
• Ex. Bees pollinate clover, clover supports
bacteria that help put nitrogen compounds
into the soil, without the nitrogen compounds
the grass would not grow and the grass eating
animals would not have anything to eat.
• One missing link and this chain falls apart
The number of populations
in an ecosystem
Swamp vs. Cornfield
Which has more populations?
Producers and Consumers
• Producers carry on Photosynthesis to produce
sugar.
• Productivity is the rate of photosynthesis
carried on by its producers. Dry Desert is not
very productive versus the Amazon Rain
Forest.
Food Chain
• 80% to 90% loss of energy in each step.
• Diagram 19 A. 11 on pg. 585
• How much energy gets to the tertiary
consumer?
Food Chain
Producers
•Plants
Primary
Consumers
•Insects and herbivores
Secondary
Consumers
•Small predators
Tertiary
Consumers
•Larger predators
Food Chain
Food Web
• Food chain is the nutritional relationship
between organisms in an ecosystem.
• Food chains are not isolated.
• Food webs show the complex relationships of
multiple food webs in an ecosystem.
Food Web
How does energy flow in an
Ecosystem?
• Ecologists use pyramid models and Food webs
to illustrate the dynamics of energy in an
ecosystem.
• Biodiversity is the number of species within a
system.
Ecological pyramid based on Energy
Biodiversity
• The number of species within a system.
• There are 23 different species of snakes in
Tennessee. 2 of which are poisonous.
• There are 21 species of frogs in Tennessee.
Species Interactions
• Neutralism – no direct connection
• Competition – competing for the same
resource
• Predation – one organism eats another
organism.
Symbiosis
• A long term relationship between two organisms.
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4 TYPES:
Amensalism – one is harmed and another is not
Parasitism – one living off of another
Commensalism – one population helped.
Mutualism – both populations helped.
Interactions in the Biosphere
• Habitat is the physical address of where an
organism lives. Ex. desert, swamp, mountains
• The niche is the organisms job or function in
the ecosystem.
Matter Cycles
• Nitrogen Cycle – short and long cycle Nitrogen is an important part of of RNA and
DNA
• Carbon Cycle – CO2 is the primary source of
carbon in living systems.
• Oxygen Cycle
Limiting Factor
• What do you think it is?
• A factor that in some way limit the growth or
existence of an organism.
• Could be food, minerals, water, temperature,
etc.
Biomes
• A major section of the biosphere that has
uniform physical environments and similar
biotic communities.
• Tundra, Coniferous Forest, Temperate
Grassland, Temperate Deciduous Forest,
Chaparral, Tropical Deciduous Forest, Savanna,
Tropical Rain Forest, Desert, Aquatic,
Mountains.
Who is this?