Ecology Introduction Ecology is a recent scientific discipline that has changed over the years both in the science itself and how it is perceived by society. In the 1800’s, German zoologist Ernst Haeckel stated that ecology was the study of the relationship between organisms and environment.

Ecology In 1954, ecology was considered to be the study of the distribution and abundance of organisms (Andrewartha and Birch 1954). This definition focused on the biotic factors and included fluctuations in climate, predators, or any changes that influence the increase in a population.

Ecology The 1970’s focused ecology on the study of ecosystems (Odum 1971) with an emphasis on man as both a positive influence and as a detriment. Man is a part of the biosphere and how he approaches both short-term and long-term problems will prove whether he is a good and wise steward of what God has given him. Genesis 3:19, 1:28, “be fruitful, and multiply” and “”subdue... and have dominion over” the earth. “

Ecology Ecology also focuses on the flow of energy throughout a system. Energy is measured in:  joules  calories  temperature

Some Key Terms Population: A group of individuals of ONE species living in one area. They interact and interbreed. Community: ALL organisms living in one area Ecosystem: all organisms in an area as well as the abiotic (nonliving) factors with which they interact.

Some Key Terms Carrying capacity: the maximum abundance of a population or species that can be maintained by a habitat or ecosystem without degrading the habitat or ecosystem’s ability to provide for future populations or species Limiting factor: a single requirement for growth available in the least amount

Abiotic Components of Ecosystems Rocks, Soil, Temp., Radiation, Wind, Atmosphere Water Other Factors –Topography: lay of the land –Ecological substrate: food sources –Fires

Biotic Community Ecological Relationships

Ecological Relationships

Autotrophs A group of organisms that can use the energy in sunlight to convert water and carbon dioxide into Glucose (food) Autotrophs are also called Producers because they produce all of the food that heterotrophs use Without autotrophs, there would be no life on this planet Ex. Plants and Algae (99% of biomass)

Autotrophs

Chemotrophs –Autotrophs that get their energy from inorganic substances, such as salt –Live deep down in the ocean where there is no sunlight –Ex. Bacteria and Deep Sea Worms Autotrophs

Organisms that do not make their own food Another term for Heterotroph is consumer because they consume other organisms in order to live Ex. Rabbits, Deer, Mushrooms Heterotrophs

Consumer Levels –1. Scavengers/Detritivores – feed on the tissue of dead organisms (both plants and animals) and recycle the nutrients for other organisms Ex. – Vultures, Crows, and Shrimp Heterotrophs

Consumers –2. Herbivores – eat ONLY plants Ex. – Cows, Elephants, Giraffes Heterotrophs

Consumers –3. Carnivores – eat ONLY meat Ex. – Lions, Tigers, Sharks Heterotrophs

Consumers –4. Omnivores – eat BOTH plants and animals Ex. – Bears and Humans Heterotrophs

Consumers –5. Decomposers – absorb any dead material and break it down into simple nutrients or fertilizers Ex. – Bacteria and Mushrooms Heterotrophs

the Transfer (loss) of Energy, Food Chains, And Food Webs

Transfer of Energy When a zebra eats the grass, it does not obtain all of the energy the grass has (much of it is not eaten, not everything is digestible). When a lion eats a zebra, it does not get all of the energy from the zebra (much of it is lost as heat)

The two (2) previous examples of energy transfer show that no organism EVER receives all of the energy from the organism they just ate. Only 10% of the energy from one trophic level is transferred to the next – this is called the 10% law.(90% is lost as heat) Transfer of Energy

Trophic Levels Energy moves from one organism to another when it is eaten. Each step in this transfer of energy is known as a trophic level –The main trophic levels are producers, consumers, and decomposers

Food Chains The energy flow from one trophic level to the other is know as a food chain A food chain is simple and direct It involves one organism at each trophic level –Primary Consumers – eat autotrophs (producers) –Secondary Consumers – eat the primary consumers –Tertiary Consumers – eat the secondary consumers –Decomposers – bacteria and fungi that break down dead organisms and recycle the material back into the environment

Food Chain

Ecological Pyramids Biodiversity Food Webs

Food Web Most organisms eat more than JUST one organism When more organisms are involved it is known as a FOOD WEB Food webs are more complex and involve lots of organisms

Food Web Notice that the direction the arrow points  is the direction of the energy transfer, NOT “what ate what”

Food Web

Biomass The total mass of the organic matter at each trophic level is called biomass Biomass is just another term for potential energy – energy that is to be eaten and used. The transfer of energy from one level to another is very inefficient (10% Law)

Biomass

Ecological Pyramid An ecological pyramid shows the relationship between consumers and producers at different trophic levels in an ecosystem Shows the relative amounts of energy or matter contained at each trophic level The Pyramid shows which level has the most energy and the highest number of organisms

Ecological Pyramid

Which level has the most energy? Which level has the most organisms? Which level has the least organisms? Which level has the least energy?

How do different species interact ?

Species Interactions Mutualism Commensalism Parasitism Neutralism

Symbiosis A close and permanent association between organisms of different species –Commensalism – a relationship in which one organism benefits and the other is not affected Example: Barnacles on a whale –Mutualism – a relationship in which both organisms benefit from each other Example: Birds eating pests off a rhino’s back –Parasitism – A relationship in which one organism benefits and the other is harmed Example: Ticks on a dog

Symbiosis A close and permanent association between organisms of different species –Neutralism – a relationship in which two different species do not affect each other –Is neutralism really possible?

Interaction Within the Biosphere Matter and Energy Range of Tolerance Nitrogen Cycle Habitats/ Niches/ Specialists, Generalists Niches and Populations

Nitrogen Cycle

Changes in the Biosphere Biorythms Succession

Remember that all life is in a ‘dynamic equilibrium’ Life forms are constantly changing their expenditure of energy in response to changes in their environment

Ecosystems and the Biosphere are also constantly adapting to shifts and changes

Example Colder than normal winter reduces the eggs of insects. Fewer insects leads to better crops and seed production. Greater seed crop increases the food supply for small rodents. More food leads to more offspring. Increased rodents provides more food to hawks. Fewer insects has a different impact on the lizards and frogs. Everything is interconnected!

Biological Rhythms result in changes in activity Diurnal: occur within a 24-hr period –Nocturnal –Diurnal Seasonal: occur over a 12 mo period –Some places have only one, some have 2 –Temperate zones have up to 6 Lunar: occur with changes in the moon –Affect mostly coastline communities and tide pools

Ecological Succession A change in the community in which new populations of organisms gradually replace existing ones Two types of succession: primary & secondary –1. Primary Succession – occurs in an area where there has been no existing communities and for some reason (s) a new community of organisms move into the area. Ex. Volcanic island

Ecological Succession A change in the community in which new populations of organisms gradually replace existing ones –2. Secondary Succession – occurs in an area where an existing community is partially damaged. –Ex.: fire, flooding, human agriculture, or industry.

Ecological Succession A change in the community in which new populations of organisms gradually replace existing ones –3. Climax Community – a community that is stable and has a great diversity of organisms.

Ecological Succession

Man in the Biosphere Man’s role as Consumer and Manager

Man’s Niche Other organisms must find a niche in their location, or move on. Man is unique Man can change his environment to supply his needs. It is OK for man to “use” his environment, depends on “how”