Unit 4: Trophic levels and ecosystenms

What do all living things need but can not create?

Energy

Where does the energy that powers the most life on Earth come from?

The sun

Autotrophs

Organisms that can capture energy from nonliving sources and convert it into forms living cells can use. Can also store them and make them available to others. (Primary producers)

Primary producers

The first producers of energy-rich compounds that can be used later by other organisms. All live depends on them.

Photosynthesis

Process done by photoautotrophs (algae and plants) Using solar energy to convert carbon dioxide and water into oxygen and energy-rich carbohydrates such as sugars and starches. Removes carbon dioxide and adds oxygen. Affects the concentration of molecules in the atmosphere. Can build living tissues.

Steps of photosynthesis

Carbon dioxide + Water + Light energy -> Carbohydrates and oxygen

Chemical formula of photosynthesis

6H20 + 6CO2 -> C6O12H6 +6O2

What do photosynthetic primary producers do?

Remove carbon dioxide from the atmosphere and add oxygen to the atmosphere.

Chemosyntetic primary producers

(chemo autotrophs) Certain bacteria can tolerate/thrive the high temperatures, total darkness, and harness the chemical energy from the inorganic compounds (hydrogen sulfide) to undergo chemosyntesis. A lot more common than you think and many live in symbiosis with other organisms.

Chemosynthesis

chemical energy is used to produce carbohydrates. Done by aphotic bacteria near sea vents, they in turn pass it off to their animal partners.

Chemosynthesis steps

Carbon dioxide + Oxygen + hydrogen sulfide chemical energy -> Carbohydrates and Sulfur compounds

Similarities between CS and PS

Both remove CO2 and produce energy rich carbohydrates.

Differences between CS and PS

CS requires dissolved oxygen and P uses water.

Heterotrophs

Organisms that cannot harness energy directly from the environment. They must acquire energy and nutrients from other organisms, usually by eating them. (Consumers)

Carnivores

obtain energy and nutrients by killing and eating other animals. (Snakes, dogs, cats, river otters).

Herbivores

obtain energy and nutrients by eating plant leaves, roots, seeds, or fruits. (Cows, caterpillars, and deer).

Scavengers

animals that consume the carcasses of other animals that have been killed by predators or have died of other causes to obtain energy and nutrients. (Vulture)

Omnivores

animals that eat both plants and animals to obtain energy and nutrients. (Humans, bears, pigs).

Decomposers

”feed” by chemically breaking down organic matter. Produces detritus, small pieces of dead and decaying plant and animal remains. (Bacteria, fungi, mushrooms, etc.)

Detritivores

Grind detritus particles into smaller pieces that can be taken in by plants. Crucial role in the ecosystem. Digest decomposers that live on, and in, detritus particles. (earthworms ,mites, snails, shrimp, crabs).

Energy always flows...

Unidirectional in one direction

Food chain

a series of steps in an ecosystem in which organisms transfer energy between trophic levels by eating and being eaten.

Food web

a complex more inclusive network of feeding interactions closer to showing all the energy interactions and mater movements in an ecosystem. Made up of food chains. So complex that it is difficult to predict exactly how they will respond to environmental change.

Decomposers _____ primary producers____ in a _____

break down; build back up; continuous cycle

Trophic level

Each step in a food chain/web. Can be illustrated by ecological pyramid.

Ecological pyramid

models that show the relative amount of energy or matter contained within each trophic level in a food chain/web.

Energy pyramid

shows the relative amount of energy available at each trophic level in a food chain/web. No limit to the amount of levels or number of organisms on that level, however only a small portion of the energy stored in any trophic level is available to the next level. (10%). This is because organisms use up much on the energy they aquire on life processes. Most is released as heat.

Biomass

the total amount of living tissue within a given trophic level. Measured in grams of organic matter per unit area. Determined by the amount of energy available to the organisms in that trophic level.

Pyramid of biomass

a model that illustrates the relative amount of living organic matter in each trophic level of an ecosystem.

Pyramid of numbers

a model that shows the relative number of individual organisms at each trophic level in an ecosystem. In most cases it is similar in shape to pyramid of biomass.

Sometimes the pryamid can be ______. Why?

Upsidedown. A single tree can feed thousands of insects.

The 6 relativly large essential nutrients

(CHNOPSK) Carbon, hydrogen, nitrogen, oxygen, phosphorus, potassium, and sulfur.

Biogeochemical cycle

process in which elements, chemical compounds, and other forms of matter are passed from one organism to another and one part of the biosphere to another. Powered by the flow of energy.

Sections of processes within biogeochemical cycles.

Biological processes, physical and chemical processes, geological processes, and processes driven by human activity.

Biological processes

any activities preformed by living organisms. (Photosysthesis, eating, respiration, eliminating waste). Mainly in biosphere but affects the other 3 as well.

Geological processes

Mainly occur in the geosphere but affect the other 3. (Volcanic eruptions, formation and breakdown of rock, major movements of matter within and below Earth’s surface.)

Physical and chemical processes

Primarily in the hydrosphere, atmosphere, and geosphere. Also can affect the biosphere. (cloud formation and precipitation, the flow of running water, and the action of lightning)

Processes driven by human activity

All four spheres leading to measurable changes in Earth’s system. (mining and burning fossil fuels, clearing of land for building and farming, cutting or burning and replanting of forests, and manufacture and use of fertilizers.)

Primary productivity

the rate at which primary producers are bale to create new organic material.
If there is ample sunlight and water, the primary productivity may be limited by the availability of nutrients.
If even a single essential nutrient is in short supply, pp will be limited.

Limiting nutrient

Any nutrient that limits the productivity of the ecosystem.

Limiting in soil

In all except the richest soil, plant growth can be limited by one or more limiting nutrients.
Fertilizer contains nitrogen, phosphorus, and potassium. Carbon is not included because plants get it from the atmosphere.

Marine

Nitrogen is the limiting nutrient. Only 0.00005%

Streams

Phosphorus is the limiting nutrient.

What happens when you add the limiting nutrients into the aquatic ecosystem?

More photosynthesis and an algae bloom.