Transcript Chapter 36
Ecology Ecology • Ecology – is the scientific study of the interactions among organisms and between organisms and their environments. Habitats • The place where an organism lives and that provides the things the organism needs is called its habitat! – Food, water, and shelter. • Biotic Factors – The living parts of an ecosystem. – Animals, plants, fungi, bacteria. • Abiotic Factors – The nonliving parts of an ecosystem. – Water, Sunlight, Oxygen, Temperature, and soil. Organism • The smallest unit of ecological study. – Wildebeest Populations • A population is a group of individual organisms of the same species living in a particular area. – Herd of Wildebeest Exponential Growth • Occurs when the population multiplies by a constant factor at constant time intervals. Limiting Factors • A factor that restricts the growth of a population. – Space – Food availability – Disease Community • All of the organisms inhabiting a particular area make up a community. Ecosystem and Biosphere • An ecosystem includes the abiotic and biotic factors in an area. • The biosphere is the sum of all Earth’s ecosystems. How do organisms get energy? • Every organism requires energy to carry out life processes such as growing, moving, and reproducing. – Producers (autotroph) – synthesize their own food through the process of photosynthesis. – Consumers (heterotrophs) – obtain their energy by eating other organisms. – Decomposers - Types of Consumers • Herbivore – eats plants. • Omnivore – eats plants and animals. • Carnivore – eats animals. Food Chains • The pathway of energy transfer form one organism to another is called a food chain. • What would happen if one organism is overhunted and removed from the food chain? • What is the source of all energy? Food Web • A pattern of feeding represented by interconnected and branching food chains is called a food web. Energy Pyramid • Emphasizes the energy loss from one organism to the next in a food chain. Only 10 % is passed on to the next level, the rest is lost to the ecosystem in the form of heat. Types of Relationships among species! • Predation – an interaction in which one organism eats another. There are two individuals that participate. • Predator and Prey • Fox is a predator and the rabbit is the prey. Symbiotic Relationships • A symbiotic relationship is a close interaction between species in which one of the species lives in or on the other. – Parasitism – one benefits and the other is harmed. – Mutualism – both species benefit – Commensalism – one benefits and the other is neither helped or harmed Ecological Succession • The process of community change is called ecological succession. • What would happen if you left the field behind Heritage uncut for a couple of years? Primary Succession • When a community arises in a lifeless area that has no soil. • Pioneer species are the first to colonize barren rock. • Climax community takes hold several hundred or thousand years later. The forest has grown to its full capacity. Secondary Succession • When a disturbance damages an existing community but leaves the soil intact, the change that follows is called secondary succession. – Fires – Land cleared for farming, then abandoned. The Carbon and Oxygen Cycle • Carbon starts its cycle in the atmosphere as Carbon Dioxide. • Plants take in the carbon dioxide and make organic compounds known as glucose. • That glucose gets passed on to consumers through the food chain. • They then release carbon dioxide back into the atmosphere through the process of cellular respiration. Human Activities can alter ecosystems! Population Growth • As the human population continues to grow, the environment will be negatively impacted by the following. – – – – – – – – – Habitat destruction Deforestation Air Pollution Acid Rain Water pollution Global Warming Introduced Species Reduced Biodiversity Overexploitation Deforestation • The clearing of forest for agriculture, lumber, and other uses also affects the carbon cycle by eliminating plants that absorb CO2 for photosynthesis. Alternatives to Clear cutting • Don’t cut down every single tree!!!!!! • Selective Cutting Greenhouse Effect • They process by which atmospheric gases trap heat. • Greenhouses trap heat. Global Warming • The overall rise in Earth’s average temperature. – Caused by increasing carbon levels in the atmosphere. • What causes increased carbon levels in the atmosphere? – Deforestation – Burning of Fossil Fuels • Effects of Global warming – Rising sea levels – Large effects on weather – Loss of Species Acid Rain • Precipitation that carries acid to the Earth’s surface. – Smokestacks and automobile exhaust pipes release nitrogen and sulfur compounds into the atmosphere. They then combine with water and form acid rain. – Can lower pH of soil and aquatic ecosystems causing species to become extinct. • Acid Rain Water and Air Pollution • Burning Fossil Fuels – Releases chemicals into the atmosphere. • Fertilizers – end up in water supplies. Introduced Species • Starlings and house sparrows are introduced species from Europe. They competed with the bluebird population drastically reducing its population. Snakeheads • Snakeheads are very aggressive and are outcompeting all native fish populations. Examples include Bass, Pickerel, Overexploitation • The practice of overhunting. – Elephants were hunted for their tusks What can Humans do to reduce our negative impact on the environment? • • • • Selective cutting Make our homes more energy efficient Use cars get higher gas mileage Tougher regulations