Chapter 2 – Introduction to Ecology Section 1: Organisms and Their Relationships

Ecology Ecology the study of the interactions between organisms and the biotic and abiotic components of their environment

The Biosphere The biosphere is the portion of Earth that supports life. “bio” means life “sphere” refers to the shape of our planet that resembles a ball “The ball of life” Includes our atmosphere, landmasses, bodies of freshwater and saltwater, and locations below the Earth’s surface that supports life.

The Biosphere Cont. Biotic Factors Abiotic Factors All of the LIVING things in an organism’s environment. Abiotic Factors All of the NONLIVING things in an organism’s environment Includes temperature, air currents, sunlight, rainfall, soil type and available nutrients

A Key Theme in Ecology No single organism is isolated!! The interconnectedness or interdependence of all organisms is central to the study of ecology The survival of organisms depends on their interactions with their surrounding environment Ex: Humans cannot live without the plants that produce food and oxygen

Levels of Organization

The Biosphere Biosphere: the broadest and most inclusive level of organization The Earth and its atmosphere make up our biosphere Extends from 8 to 10 km (5-6 miles) above the Earth’s surface to the deepest parts of the ocean

Ecosystems The biosphere is comprised of smaller units called ecosystems Includes all of the organisms and the abiotic environment found in a specific place Ex: Pond Ecosystem Abiotic components: water temperature, amount of dissolved oxygen and carbon dioxide, the pH level Biotic components: insects, fish, algae, aquatic plants, turtles Some ecosystems can be considered the habitat of an organism.

Chapter 18 Ecosystem

The Niche Niche the role an organism plays in its environment Includes: Range of conditions the organism can tolerate Methods by which it obtains resources Interactions with its environment such as reproduction

Earthworms Niche

Community Interactions all of the interacting organisms living in an area Ex: All of the fish, turtles, insects, plants and algae make up the community of a pond Competition occurs when more than one organism uses a resource at the same time. Ex: Lions and hyenas compete for the same food sources. Predation is the act of one organism consuming another for food.

Chapter 18 Community

Symbiotic Relationships Most species survive because of relationships called symbiosis Mutualism: Both organisms benefit Ex: The Egyptian plover takes insects from the backs of buffaloes, giraffes and rhinos

Symbiotic Relationships Commensalism: One benefits; the other is not affected Ex: Sea anemone and the clown fish. Parasitism: One benefits at the expense of the other Ex: Deer tick and mammal

Visual Concept

Chapter 2 – Principles of Ecology Section 2: Flow of Energy in an Ecosystem

Energy in an Ecosystem Autotrophs: primary producers make their own food Use energy from sunlight or inorganic substances Foundation of all ecosystems they make energy available for all of the other organisms Ex: Plants

Energy in an Ecosystem Heterotrophs: get energy by consuming other organisms Called “consumers” Herbivores eat only plants Carnivores eat others

Energy in Ecosystems Heterotrophs Cont: Omnivores Detrivores eat both plants and animals Detrivores eat dead/decaying material Decomposers are similar to detrivores Break down dead organisms by releasing digestive enzymes (fungi) Important because they make nutrients available for all other organisms

Models of Energy Flow Ecologists use food chains and food webs to show energy flow in ecosystems Trophic level Each step in a food chain or food web Autotrophs are the first trophic level in ALL food chains and food webs!

Important Terms for Food Chains and Food Webs Primary producers: make their own food Primary consumers: eat the primary producers Secondary consumers: eat the primary consumers Third-level consumers: eat the secondary consumers

Food Chains Food chains: a simple model that shows how energy flows through an ecosystem Arrows show one-way energy flow Each organism uses some of the energy from the organism it eats The remaining energy is lost to the surrounding environment

Food Webs Food webs: models that represent the interconnected food chains in which energy flows through a group of organisms

Ecological Pyramids Diagrams that show the relative amounts of energy, biomass or numbers of organisms at each trophic level Biomass is the total mass of living matter at each trophic level Approximately 90% of all energy at a tropic level is NOT transferred to the level above it

The Biogeochemical Cycles

Cycles of the Biosphere Energy is not recycled in a ecosystem Matter (biomass) is recycled in a ecosystem Nutrient: a chemical substance that an organism needs from its environment. Nutrient cycling involves both the biotic and abiotic portions of an ecosystem. These are called the biogeochemical cycles.

The Water Cycle: more of a physical process than a chemical one.

The Water Cycle Key Terms: Evaporation: water returning to the atmosphere from oceans, lakes, and rivers Transpiration: water returning to the atmosphere from the surface of plants Precipitation: water returning to the earth from the atmosphere Percolation: water running through the soil Runoff: water running on the surface of the earth.

The Carbon Cycle Two natural processes help to cycle carbon through the ecosystem. Photosynthesis: autotrophs take in CO2 and produce organic compounds Make them available then for consumers. Cellular Respiration; both autotrophs and heterotrophs convert energy rich organic compounds into ATP powers cellular functions.

The Carbon Cycle Deposition Carbonate in sediments: dead materials: converted to peat, coal, oil or gas deposits (carbon stored as fossil fuel) carbon is released when fossil fuels are burned Carbonate in sediments: shells, coral, algae fall to bottom of ocean creating limestone rock. Carbon is released in the form of bicarbonates

The Carbon Cycle

There are none! Brain Break Try to count the number of black dots on the image below... There are none!

The Nitrogen Cycle Nitrogen enters ecosystems through two natural pathways. Nitrogen fixation, where certain bacteria convert N2 to minerals that can eventually be used by plants to produce nitrogenous organic compounds.

The Nitrogen Cycle Chemical nitrogen fixation - lighting bolts change nitrogen gas to nitrates or nitrogen is added to the soil by chemical fertilization. Some bacteria break down detritus and animal waste producing ammonium through Ammonification Certain bacteria convert ammonium into nitrate, a process called Nitrification. Nitrate can be used by plants.

The Nitrogen Cycle Some bacteria take oxygen from the nitrate and release N2 back into the atmosphere called Denitrification.

WHAT IS PRODUCED (Products) PROCESS By What Organism Compounds Used WHAT IS PRODUCED (Products) NITROGEN FIXATION Nitrogen fixing bacteria in soil and in legume roots. Nitrogen Gas (N2) Usable nitrogen: Nitrates (NO3-) made in roots of legumes and Ammonium (NH4+) and in the soil. AMMONIFICATION Decomposers (Bacteria and Fungus) Detritus and waste Ammonia NITRIFICATION Nitrifying Bacteria Ammonium Nitrites (NO2-) & NO3- ASSIMILATION Chemical reactions in the organism. Nitrates Any nitrogen based compound needed by plants and animals. Nitrogen is used to make amino acids. DENITRIFICATION Denitrifying Bacteria Excess nitrates Nitrogen Gas

Phosphorus cycle

Phosphorus cycle Needed for growth and development Short term- cycled from soil to producers and producers to consumers Long term- Phosphorus comes from weathering and erosion of rocks

Rates of nutrient cycling Decomposition rates largely determine the rates of nutrient cycling The rate at which nutrients cycle in an ecosystem depends on the rate of decomposition. Decomposition can take up to 50 years in the tundra, while in the tropical forest, it occurs much faster. Quantities of nutrients in the soil of different ecosystems also varies, depending on the rate of absorption by the plants.

Nutrient cycling is strongly regulated by vegetation In a terrestrial ecosystem most of the mineral nutrients cycle within the ecosystem. In addition to the natural ways, nitrogen- containing fertilizer contributes to the total amount of nitrogen materials in ecosystems.

The End see it wasn’t that bad 