Lesson Overview Lesson Overview What is Ecology? Chapter 3 Ecosystems

Lesson Overview Lesson Overview What is Ecology? Ecology - study of interactions among and between organisms and their environment. Make a list of all the living thing and the non living things.

Lesson Overview Lesson Overview What is Ecology? Factors that influence an ecosystem A biotic factor - LIVING part of the ecosystem, including animals, plants, mushrooms and bacteria. An abiotic factor - NONLIVING part, such as sunlight, heat, precipitation, wind/ water currents, soil type, etc.

Lesson Overview Lesson Overview What is Ecology? Levels of Organization Biosphere—our entire planet. Biome—a group of ecosystems that share similar climates and typical organisms Ecosystem—all the organisms that live in a place, together with their physical environment Individual organism – ONE moose. Population— TWO or MORE moose. Community— moose AND rabbits AND hawks.

Lesson Overview Lesson Overview What is Ecology? Food Chains A food chain is a series of steps in which organisms transfer energy by eating and being eaten. Food chains can vary in length as shown below

Lesson Overview Lesson Overview What is Ecology? Primary Producers Make their own food for energy and nutrients Ex. Autotrophs – plants do photosynthesis and some bacteria do chemosynthesis Consumers eat other organisms for energy and nutrients. Ex. Heterotrophs - ingesting organisms somehow

Lesson Overview Lesson Overview What is Ecology? Types of Consumers Carnivores - kill and eat other animals Herbivores - eat plant leaves, roots, seeds, or fruits. OmnivoresOmnivores - animals whose diets naturally include a variety of both plants and animals. Decomposers/detritivore - break down dead organic matter.

Lesson Overview Lesson Overview What is Ecology? Food Webs In most ecosystems, feeding relationships are much more complicated than the relationships described in a single, simple chain because many animals eat more than one kind of food. Each path through a food web is a food chain.

Lesson Overview Lesson Overview What is Ecology? Decomposers and Detritivores in Food Webs decomposers convert dead material to detritus, which is eaten by detritivores, such as crayfish, grass shrimp, and worms. Pig frogs, killifish, and other fishes eat the detritivores. The decomposition process releases nutrients that can be used by primary producers  recycling Without decomposers, nutrients would remain locked in dead organisms.

Lesson Overview Lesson Overview What is Ecology? Food Webs and Disturbance In recent years, krill populations have dropped substantially. Given the structure of this food web, What would happen to the other members of the food web shown?

Lesson Overview Lesson Overview What is Ecology? Trophic Levels Each step in a food chain or food web is called a trophic level. Primary producers always make up the first trophic level. Various consumers occupy every other level. Some examples are shown.

Lesson Overview Lesson Overview What is Ecology? Pyramids of Energy Organisms use energy they acquire on life processes; respiration, growth, reproduction. (90%) Remaining energy is released as heat. about 10% is available to transfer to the next trophic level.

Lesson Overview Lesson Overview What is Ecology? Pyramids of Biomass and Numbers Total amount of living tissue within a given trophic level  biomass. Pyramid of biomass  relative amount of living organic matter at each trophic level- greatest biomass  base Pyramid of numbers  relative number of individual organisms at each trophic level in an ecosystem.

Lesson Overview Lesson Overview What is Ecology? Pyramids of Biomass and Numbers In some cases, however, consumers are much smaller than organisms they feed upon. Thousands of insects may graze on a single tree, for example. The tree has a lot of biomass, but represents only one organism. In such cases, the pyramid of numbers may be turned upside down, but the pyramid of biomass usually still has the normal orientation.

Lesson Overview Lesson Overview What is Ecology? Recycling in the Biosphere Unlike the flow of energy (food chain), matter is recycled within ecosystems. Atoms are passed from organisms to other parts of the biosphere through biogeochemical cycles, powered by the flow of energy. As matter moves through these cycles, it is never created or destroyed—just changed.

Lesson Overview Lesson Overview What is Ecology? Human Activity Human activities that affect cycles of matter on a global scale include: mining and burning of fossil fuels clearing of land for building and farming burning of forests manufacture and use of fertilizers

Lesson Overview Lesson Overview What is Ecology? The Water Cycle Water continuously moves between the oceans, the atmosphere, and land—sometimes outside living organisms and sometimes inside them.

Lesson Overview Lesson Overview What is Ecology? Nutrient Cycles Oxygen participates in parts of the carbon, nitrogen, and phosphorus cycles by combining with these elements and cycling with them through parts of their journeys. Oxygen gas in the atmosphere is released by one of the most important of all biological activities: ????? Oxygen is used in respiration by all multicellular forms of life, and many single-celled organisms as well.

Lesson Overview Lesson Overview What is Ecology? The Carbon Cycle Carbon is a major component of all organic compounds, including c___________, l________, p_________, and n_______ a______.

Lesson Overview Lesson Overview What is Ecology? The Nitrogen Cycle All organisms require nitrogen to make amino acids, which are used to build ___________ and nucleic acids, which combine to form DNA and RNA. Nitrogen gas (N 2 ) makes up 78 percent of Earth’s atmosphere.

Lesson Overview Lesson Overview What is Ecology? The Nitrogen Cycle Certain bacteria convert nitrogen gas into ammonia, in a process known as nitrogen fixation. Other soil bacteria convert fixed nitrogen into nitrates and nitrites that primary producers can use to make proteins and nucleic acids. Yet other bacteria convert nitrates into nitrogen gas  denitrification.

Lesson Overview Lesson Overview What is Ecology? The Phosphorus Cycle Phosphorus forms a part of vital molecules such as DNA and RNA. Although phosphorus is of great biological importance, it is not abundant in the biosphere. Plants bind phosphate into organic compounds when they absorb it from soil or water.

Lesson Overview Lesson Overview What is Ecology? Nutrient Limitation Most fertilizers contain large amounts of nitrogen, phosphorus, and potassium, which help plants grow better in poor soil. Runoff with excess fertilizers can cause an algal bloom—a dramatic increase in the amount of algae and other primary producers due to the increase in nutrients.