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  "Lil' Erik" Photo by Kristin King 2002

Dinosaur Data

Ecology is the scientific study of interactions which determine the distribution and abundance of organisms.  Ecology is part of a broader realm of science (physical and biological), having vital roots in plant geography and natural history and makes predictions on how various things effect us.

Basic questions addressed by ecologists:
1. Where are the organisms?
2. How many are there?
3. Why do they occur there?

Complex Problems:

our world ~ Click here

1. Human Population Growth
2. Global Climatic Change
4. Cumulative Impact on Development
5. Extinction of Species
6. Toxic Substances in the Environment
7. Genetic Engineering

Diversity of Life

Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com), used with permission.


 Classification, or taxonomy, is a system of categorizing living things. There are seven divisions in the system: sea star

  •  Kingdom
  •  Phylum or Division
  •  Class
  •  Order
  •  Family
  •  Genus
  •  Species

Kingdom is the broadest division. There is no agreement about the number of kingdoms, but most scientists support a four-kingdom (Animalia, Plantae, Protista, and Monera) or five-kingdom (Animalia, Plantae, Protista, Monera, and Fungi) system. For our purposes, we will use the five-kingdom system.

  See Biology page for more Taxonomy Information.

 Practice with genus and species...


Casuarius casuarius


                                                                                   Photos by Mrs. King  at the Brevard ZOO



Corn Snake

Pantherophis guttatus

Hypomelanistic (back) & Albino Amelanistic (front)

Eastern  United States

Bearded Dragon

Pogona vitticeps

Bearded Dragon


Prairie Dog

Cynomys ludovicianus


Native to North America


Energy Flow Through The Ecosystem

Ecosystems are comprised of a combination of biotic (living) and abiotic (non-living) components where energy flows in the form of carbon-carbon bonds  and materials are recycled. Energy, however, does not recycle.

When respiration occurs, the c-c bonds are broken and the carbon is combined with oxygen to form CO2 This process releases the energy which is either used by the organism ( to move muscles, digest food, excrete wastes, think, etc.) or the energy may be lost as heat.


How Earth's Ecosystems Work

Ecosystems include both living and nonliving components. These living, or biotic, components include habitats and niches occupied by organisms. Nonliving, or abiotic, components include soil, water, light, inorganic nutrients, and weather. An organism's place of residence, where it can be found, is its habitat. A niche is is often viewed as the role of that organism in the community, factors limiting its life, and how it acquires food. 

Producers, a major niche in all ecosystems, are autotrophic, usually photosynthetic, organisms. In terrestrial ecosystems, producers are usually green plants. Freshwater and marine ecosystems frequently have algae as the dominant producers. 

Consumers are heterotrophic organisms that eat food produced by another organism. Herbivores are a type of consumer that feeds directly on green plants (or another type of autotroph). Since herbivores take their food directly from the producer level, we refer to them as primary consumers. Carnivores feed on other animals (or another type of consumer) and are secondary or tertiary consumers. Omnivores, the feeding method used by humans, feed on both plants and animals. Decomposers are organisms, mostly bacteria and fungi that recycle nutrients from decaying organic material. Decomposers break down detritus, nonliving organic matter, into inorganic matter. Small soil organisms are critical in helping bacteria and fungi shred leaf litter and form rich soil. 

Even if communities do differ in structure, they have some common uniting processes such as energy flow and matter cycling. Energy flows move through feeding relationships. The term ecological niche refers to how an organism functions in an ecosystem. Food webs, food chains, and food pyramids are three ways of representing energy flow.

Producers absorb solar energy and convert it to chemical bonds from inorganic nutrients taken from environment. Energy content of organic food passes up food chain; eventually all energy is lost as heat, therefore requiring continual input. Original inorganic elements are mostly returned to soil and producers; can be used again by producers and no new input is required.

Energy flow in ecosystems, as with all other energy, must follow the two laws of thermodynamics. The first law states that energy is neither created nor destroyed, but instead changes from one form to another (potential to kinetic). The second law states that when energy is transformed from one form to another, some energy is lost as heat. This means in any given food chain some energy must be lost as we move up the food chain. 

The main source of energy for almost all forms of life is the Sun.   Scientists discovered an exception, communities of organisms around ocean vents where food chains begin with chemosynthetic bacteria.  These organisms oxidize hydrogen sulfide generated by inorganic chemical reactions inside the Earth's crust. Their source of energy is the internal heat of the Earth instead of the heat of the Sun. 

Food chains indicate who eats whom in an ecosystem. Natural ecosystems have numerous interconnected food chains, much like a complex web. Each level of producer and consumers is a trophic level. Some primary consumers feed on plants and make grazing food chains; other consumers like mushrooms feed on detritus.

The population size in an undisturbed ecosystem is limited by the food supply, competition, predation, and parasitism.
The trophic structure of an ecosystem forms an ecological pyramid. The base of this pyramid represents the producer trophic level. At the apex, or top, is the highest level consumer or top predator. The pyramid of biomass is calculated by multiplying the average weight for organisms times the number of organisms at each trophic level. We can use an energy pyramid illustrates the amounts of energy available at each successive trophic level. The energy pyramid always shows a decrease moving up trophic levels because: 

  • Only a certain amount of food is captured and eaten by organisms on the next trophic level. 
  • Some of food that is eaten cannot be digested and exits digestive tract as undigested waste. 
  • Only a portion of digested food becomes part of the organism's body; rest is used as source of energy. 
  • Substantial portion of food energy goes to build up temporary ATP in mitochondria that is then used to synthesize proteins, lipids, carbohydrates, fuel contraction of muscles, nerve conduction, and other functions. 
  • Only about 10% of the energy available at a particular trophic level is incorporated into tissues at the next level. Therefore, a larger population can be sustained by eating grain than by eating grain-fed animals since 100 kg of grain would result in 10 human kg but if fed to cattle, the result, by the time that reaches the human is only 1 human kg.

A food chain is a series of organisms each feeding on the one preceding it. 

There are two types of food chains: 

 Decomposer - chains are composed of waste and decomposing organisms such as fungi and bacteria.
Grazer - food chains begin with algae and plants and end with a carnivore.

primary producer
primary consumer
secondary consumer
tertiary consumer


Food chains are simplifications of complex relationships. A food web is a more realistic and accurate representation of energy flow. Food webs are networks of feeding interactions within any given species.

The food pyramid provides a detailed view of energy flow in an ecosystem. The first level consists of the producers (usually plants). All higher levels are consumers. The shorter the food chain the more energy is available to organisms. 

Most humans occupy a top carnivore role, about 2% of all calories available from producers ever reach the tissues of top carnivores. Leakage of energy occurs between each feeding level. Most natural ecosystems therefore do not have more than five levels to their food pyramids. Large carnivores are rare because there is so little energy available to them at the top of the pyramid.

Food generation by producers varies significantly between ecosystems. Net primary productivity (NPP) is the rate at which producer biomass is formed. Tropical forests and swamps are the most productive terrestrial ecosystems. Reefs and estuaries are the most productive aquatic ecosystems. All of these productive areas are in danger from human activity. Humans redirect nearly 40% of the net primary productivity and directly or indirectly use nearly 40% of all the land food pyramid.

Photosynthesis and Respiration


Where  In cholorophyll-bearing cells 
When:  In the presence of light 
Input:  Carbon dioxide and water 
Output: Reduced carbon compounds, oxygen, and water 
Energy sources: Light 
Energy result: Energy stored 
Chemical reaction: Reduction of carbon compounds 
Energy carrier: NADP 

Where: In all cells 
When: All the time 
Input: Reduced carbon compounds and oxygen 
Output: Carbon dioxide and water 
Energy Sources: Chemical bonds 
Energy Result: Energy released 
Chemical reaction: Oxidation of carbon compounds 
Energy Carriers: NAD and FAD 

The Krebs Cycle:

NAD, FAD and ATP are all involved in the Krebs Cycle- a process for energy and metabolism. 
NAD is an electron carrier, FAD is an electron acceptor, and ATP is the energy currency of the cell.

 Electron Transport


Plant Structure

Orientation of sections for the study of wood anatomy. (A) Transverse; (B) longitudinal; (C) tangential.



Detail of a mature vascular bundle in maize

Lilac leaf

  Monocot & Dicot Imagery


Biogeochemical Cycles

The world as we know it is made up of cycles and systems.

 Nitrogen Cycle  

Phosphorous Cycle

The Carbon Cycle

Oxygen Cycle

The Water Cycle


The Rock Cycle


Geologic Time Rock Cycle (Beyond Books)
Rock Cycle

Renewable & Non-renewable Energy


Fire in the Ecosystem







Beneath the Sea

My classroom salt water tank 

Coral reef tank    Shrimp


Coral Reef

Earth Labs


The Amazing Ants



American Cockroach

Periplaneta americana  

American Roach

Cockroach Anatomy



Last modified: January 19, 2018