Ecosystem Dynamics

Ev Sci Ch 3

Ecosystem Dynamics

Open Ended

What are earth's major systems, and how do they support life?

Open Ended

What are the major ecosystem components?

Open Ended

What happens to energy in an ecosystem?

Open Ended

What happens to matter in an ecosystem?

What are Earth’s Major spheres, and how do they support life?

• Earth’s spheres function as a life-support system

• Interaction among atmosphere, hydrosphere, geosphere, and biosphere

• Natural capital is the product of earth’s spheres and energy from the sun

The Geosphere

• Earth’s core, mantle, thin outer crust

• Creates the gravitational force needed to keep the atmosphere from escaping into space.

• Contains nutrients organisms need, and nonrenewable fossil fuels and mineral resources

The Atmosphere

• Envelope of gases surrounding the planet

• Shields planet from meteors, and UV rays

• Regulates earth’s climates

The Trophosphere

• lowest layer of the atmosphere, where can sustain life

• Weather occurs here

Stratosphere

• Above troposphere

• Also known as the ozone layer

• Absorbs 95% of UV

• Next 3 layers are mesosphere, thermosphere, and exosphere

The Hydrosphere

• All water associated with earth.

• All gaseous, solid, liquid water on or near the surface

The Biosphere

• Where life exists

Earth’s spheres interact

• Greenhouse effect - solar energy reflected from earth’s surface (geosphere) is absorbed by troposphere and reacts with greenhouse gases

Greenhouse effect

• Warms the earth

• Without it, earth could not sustain life because the earth would be too cold

• Interactions between the spheres naturally clean the earth.

• Plants absorb and evaporate water, pollutants are absorbed.

Multiple Choice

What is the atmosphere?

• Layer of gases around the planet

• Crust, mantle, core

• Water

• Life

Multiple Choice

Which is the lowest layer of the atmosphere, where weather occurs?

• Troposphere

• Stratosphere

• Mesosphere

• Exosphere

Multiple Choice

All of the water on the planet makes up the...

• Atmosphere

• Troposphere

• Hydrosphere

• Biosphere

Multiple Choice

Which of these things would you find in the biosphere?

• Plants, Animals

• Water

• Sunlight

• All of these

What are the major ecosystem components?

• Ecologists assign every organism to a trophic level - level of the food chain

• Producers - Make food from photosynthesis

Producers

• Take solar energy and turn it into chemical energy

• In an open water ecosystem, producers would be phytoplankton

Consumers

• get food by feeding on other producers or consumers

• Primary consumers - also know as herbivores - eat green plants and algae

• Secondary consumers - animals that feed on primary consumers

• Tertiary consumers - feed on primary and secondary consumers

Consumers

• Carnivores - feed on other animals

• Omnivores - Eat plants and animals

• Decomposers - consumers that get food by breaking down nonliving organic matter things (tree, animals, etc)

• Detritivores - consume freshly dead organisms

Cellular respiration

• Organisms use chemical energy of glucose to fuel life processes

• This energy is then released by aerobic respiration - uses oxygen and glucose to produce energy

• Decomposers break down glucose in the absence of oxygen to obtain energy, this is known as anaerobic respiration (another word for it is fermentation)

What happens to energy in an ecosystem?

• Food chains and food webs

• Primary productivity

Food chains and food webs

• Describes how energy moves through an ecosystem

• Food chain - sequence of organisms that serve as food for the next level

• Food web - complex network of interconnected food chains.

Primary Productivity

• Study the rates at which ecosystems produce chemical energy to compare ecosystems and understand how they interact

• Gross primary productivity - rate at which producers create their chemical energy

Primary productivity

• Net primary productivity - rate at which producers use photosynthesis to produce and store chemical energy, minus the rate at which they use some of this energy for cellular respiration

• Tropical rainforests have high NPP; large abundance of plants

• Open ocean has low NPP

What happens to matter in an ecosystem

• Nutrients cycle within and among ecosystems

• Hydrologic cycle - water cycle

• Carbon Cycle

• Nitrogen cycle

Nutrients cycle within and among ecosystems

• Movement of matter occurs within the biosphere in Nutrient cycles 

• Nutrient cycles are also known as biogeochemical cycles.

Biogeochemical cycles

• Driven directly by solar energy

• Cycles include hydrologic, carbon, nitrogen, and phosphorus cycles

Hydrologic cycle - water cycle

• Collects, purifies, and distributes earth’s fixed supply of water

• Solar energy causes evaporation, which rises and condenses into clouds, gravity then draws water back down as precipitation

Hydrologic cycle

• 90% of water in atmosphere evaporated from soil and plants

• Most precipitation falling back on land becomes surface runoff - flows over land surfaces into streams, rivers, lakes, wetlands, and oceans, where it can evaporate.

• Water that seeps deeper through soil is groundwater

• Groundwater collects in aquifers - underground layers of sand, gravel, and water bearing rock.

Hydrologic cycle

• Human impacts

• People drain and fill wetlands for farming and urban development

• Causes flooding because wetlands absorb a lot of water

• People withdraw fresh water from rivers, lakes, aquifers

• People clear vegetation from land for agriculture, mining, road building, and other activities.

• Increases runoff and reduces infiltration that normally recharges groundwater supplies

Carbon Cycle

• Carbon is building block for all organic compounds in your body

• Carbon cycle - different compounds of carbon circulate through the biosphere, atmosphere, and other parts of geosphere and hydrosphere

Carbon Cycle

• Key component of carbon cycle is carbon dioxide

• Photosynthesis moves carbon from atmosphere to the biosphere

• Aerobic respiration releases carbon dioxide to the biosphere

• Human impacts

• Humans are adding large amounts of carbon dioxide to the atmosphere, altering the carbon cycle

Nitrogen Cycle

• Nitrogen makes up 78% of the volume of the atmosphere

• Can not be absorbed as used directly as a nutrient

• Usable by producers in the form of ammonia

Nitrogen cycle

• Nitrogen cycle - ammonia is created through lightning or specialized bacteria found in topsoil and aquatic ecosystems

• Plant roots take up nitrogen to produce proteins, nucleic acids, and vitamins for their own survival.

• Organisms that consume these plants also consume the nitrogen

• Nitrogen is returned to the environment as wastes and cast off particles of matter such as leaves.

Nitrogen Cycle

• Human impacts

• Mining of large amounts of phosphate to make fertilizer