Transcript Slide 1
Introduction to Ecology What is the layer of the Earth called where all living organisms are located? What is Ecology? • The study of interactions between organisms and the living and nonliving components of their environment • From Greek oikos, meaning “house,” and logos, meaning “study of.” What does ecology involve? Bird Migratory Patterns • Collecting information about organisms and their environments • Observing and measuring interactions • Looking for patterns • Seeking to explain patterns Interdependence • Interaction of organisms with other organisms in their surroundings, and the nonliving portion of their environment • What is one way humans are dependent? Effects of Interdependence • One single change can spread throughout a whole level of interactions!!! • How could humans be affected by acorns? Ecological Models • These represent or describe the components of an ecological system • Can be physical, conceptual, or mathematical • Used to help plan and evaluate solutions to environmental problems Ecological Models • Help us understand environmental interactions and make predictions about changes • Can be tested by comparison to the natural world • Why can these models be limited? Five Levels of Ecological Organization Biosphere • Broadest , most inclusive level • About 20 km (13 mi) thick • Thin film of life covering an otherwise lifeless planet Ecosystems • All of the organisms and the non-living environment found in a particular place • What would be included in a pond’s ecosystem? Communities • All interacting organisms living in an area • Ecologists studying communities look at how species interact • What would be involved in the pond’s community? Populations • All members of a single species that live in one place at one time. • What would be an example of various populations in a pond? Organism • The simplest level of organization in ecology • Research at this level concentrates on the adaptations that allow organisms to overcome the challenges of their environment Review True or False??? Geology is the study of the interactions between organisms and the environment? FALSE!!!! The study described is Ecology! FALSE!!!! They can be verbal, visual (like the True or False? picture here), or mathematical! All ecological models are mathematical. Energy Transfer in an Ecosystem Why do organisms need energy? • To carry out essential functions – – – – – Growth Movement Maintenance Repair Reproduction Autotrophs What is the main energy source for life on earth? Sun Organisms that eat autotrophs Organisms that eat other organisms The amount of energy an ecosystem receives and the amount that is transferred from organism to organism affect the ecosystem’s structure!!!!! Producers • Organisms that manufacture their own foods by capturing energy and using it to make organic molecules – Plants (Terrestrial) – Some protists (Aquatic) – Some bacteria (Aquatic) Producers • Photosynthetic – Use solar energy to power the production of food • Chemosynthetic – Use energy stored in inorganic molecules to produce carbohydrates Measuring Productivity by Producers • Gross primary productivity – Rate at which producers capture the energy of sunlight by producing organic compounds • Net primary productivity – The rate at which biomass accumulates – Expressed in either: • Units of energy per unit area per year (kcal/m2/y) • Units of dry organic mass per unit area per year (g/m2/y) Biomass – Organic material produced – Only energy stored as biomass is available to other organisms in ecosystems Consumers • Heterotrophs that cannot manufacture their own food • Get energy by eating other organisms or organic wastes • All animals, most protists, all fungi, many bacteria Types of Consumers • What are 4 types of consumers? – – – – Herbivores Carnivores Omnivores Detritivores Herbivores vs. Detritivores Herbivores • Eat producers • Ex] Giant panda Detritivores • Feed on the “garbage” of an ecosystem – Ex] Earthworm • Waste, such as dead organisms, fallen leaves, and wastes = detritus • Decomposers are those bacteria and fungi that cause decay by breaking down complex molecules Carnivore vs. Omnivore Carnivore • Eat other consumers • Ex] Lions Omnivore • Eat both consumers and producers • Ex] Pigs Create your own graphic • Label the types of organisms according to energy flow Producers: make energy-storing molecules Herbivores: consume producers Omnivores: consume producers & herbivores Detritivores: consume producers, herbivores, carnivores, and omnivores Carnivores: consume herbivores Energy Flow • When an organism eats another, energy is transferred • Therefore energy flows from producers to consumers • Group organisms based on energy flow in an ecosystem Food Chains and Food Webs Food Chain • A single pathway of feeding relationships in an ecosystem Food Web • Interrelated pathway of food chains in an ecosystem Feeding Relationships • Trophic levels – each step in a food chain or food web – 1st – producers – 2nd – primary consumers – 3rd – secondary consumers – 4th – tertiary consumers Ecological Pyramids • Energy Pyramid – shows the amount of energy available at each trophic level – Only about 10% of the energy is transferred to the next level • Biomass Pyramid – shows the amount of living tissue within each trophic level • Pyramid of numbers – shows the number of organisms at each trophic level Ecological Pyramids Energy Transfer • On average, only 10% of the total energy consumed in one level is incorporated into the next level. • Why so low? – Some escape being eaten – Some die and decompose – Some used for cellular respiration – Some can’t be broken down – Some lost as heat from metabolism Limitations of Trophic Levels • Low rate of energy transfer explains why there are only a few trophic levels in an ecosystem • High trophic levels contain less energy, so they can only support a few individuals What is the organic material in an ecosystem called? What is an organism called that eats both producers and consumers? How much of the total energy is transferred from one trophic level to the next?