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=pgPhn4tYxJQ

• 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

• 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 populationsin an ecosystem

Swamp vs. CornfieldWhich 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.

• 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?