Transcript Food Web
Ecology Interactions of Living Things Fact or Fib Sea otters wrap themselves in a blade of kelp to keep from drifting while they sleep. FACT Blades of kelp can grow as tall as the Statue of Liberty and they can be useful to sea otters. Fact or Fib Many animals prefer to live in areas with acidic soil. FIB Acidic soil limits the number of plants that will grow and therefore limits the food source for many animals. Fact or Fib The Australian mallee fowl relies on bacteria and fungus to regulate the temperature of its nest. Fact As they decompose leaves on the nest, they give off heat. When it’s just the right temperature, the birds lay their eggs. Fact or Fib Alligators make homes for fish and other aquatic life. FACT They dig a hole for themselves and when they leave that hole is inhabited by other animals. What is common in each of these? Australian mallee rely on bacteria and fungus. Sea otters rely on kelp. Some aquatic animals rely on alligators. Many animals rely on fertile soil. All living things are connected. What do we call the study of relationships among organisms? Ecology Lesson 1- Matter, Energy, & the Environment Ecology is the study of the interactions between organisms and the environment An organism’s environment is anything that affects the organism including living & non-living factors Living vs. Not Living Factors Biotic- living things • Examples: Animals Plants Bacteria Abiotic- non-living things • Examples: The sun Climate- average weather conditions in an area over time Temperature Water Atmosphere- layer of gases that surround Earth Soil If either a biotic or abiotic factor is disturbed, other parts of the ecosystem are affected. biotic from Greek biotikos, means “fit for life” Living Things Need Energy Organisms in an ecosystem can be divided into 3 groups based on how they obtain energy. Producers • Use sunlight to make food using photosynthesis Plants Some Algae Some Bacteria Consumers • Eat producers or other organisms • They cannot directly use sunlight Herbivores- plant eaters Carnivores- meat eaters Omnivores- eat both meat & plants Scavengers- feed on bodies of dead animals Decomposers • • • Break down the remains of dead organisms. Natures recyclers because they produce simpler material such as water and carbon dioxide. Examples: bacteria and fungi How does energy move through ecosystems? In most cases, energy flow begins with the Sun and moves from one organism to another. Food Chain A model that shows how energy flows in an ecosystem through feeding relationships. In a food chain, arrows show the transfer of energy. •The amount of available energy decreases every time it is transferred from one organism to another. Food Web Food webs illustrate all the complex feeding relationships in a real ecosystem. Some organisms in a food web might be part of more than one food chain in that web. Few organisms eat just one kind of food There are many possible connections Food chains & Food webs video clip Energy Pyramid shows the amount of energy available in each step of a food chain. • The steps of an energy pyramid are called trophic levels. • Producers, such as plants, make up the trophic level at the bottom of the pyramid • Consumers that eat producers make up the next trophic level. • Consumers that eat other consumers make up the highest trophic level. • Less energy is available for consumers at each higher trophic level. Energy Pyramid video clip What would happen to the food web if a specific organism were removed? Gray wolves were almost wiped out when the US wilderness was settled This caused the elk population to increase. How do you think the fox population was effected by this? Their population decreased…why? Here’s why. Wolves eat elk Elk graze Overpopulation of elk causes overgrazing This means, there is not enough food for hares which also means not enough food for foxes. How do wolves help the community? Wolves kill old, injured, or diseased elk and regulate the populations in the community. How would the introduction of an exotic (invasive) species affect the food web? •Mute swans were brought to the Hudson River Valley during the 19th century to ornament the estates of the wealthy. •They consume enormous quantities of submerged aquatic vegatation (SAV) and edge other waterfowl out of their habitats. A thought to take with you. • When one tugs at a single thing in nature, he finds it attached to the rest of the world." Muir, John Naturalist, Preservationist and Founder of the Sierra Club (1838-1914) Lesson 2- Populations & Communities 5 Levels of the environment Individual organism 5 Levels of the environment A group of individuals of the same species that live together in the same area at the same time make up a population. 5 Levels of the environment All populations of different species that live in the same area make up the community 5 Levels of the environment Community plus abiotic factors make up the ecosystem 5 Levels of the environment Anywhere that life exists is the biosphere • From the deepest parts of the ocean to very high up in the atmosphere Population Sizes Changes in environmental factors can result in population size changes. • Populations cannot grow indefinitely • Environments only contains so much food, water, living space, and other resources When one of these becomes scarce, it is said to be limiting A limiting factor is anything that restricts the size of a population. • Available sunlight is a limiting factor for most organisms. • Without sunlight, green plants cannot make food, which effects animals that eat plants. Population Sizes Temperature is a limiting factor for some organisms. • When the temperature drops below freezing, many organisms die because it is too cold to carry out their life functions. • Disease, predators, and natural disasters such as fires or floods are also limiting factors. Population Sizes The largest number of individuals of one species that an environment can support is the carrying capacity A population grows until it reaches the carrying capacity of an environment. Carrying capacity is determined in part by limiting factors The carrying capacity of an environment is not constant because it increases and decreases as the amount of available resources increases and decreases. When the size of a population becomes larger than the carrying capacity of its ecosystem, overpopulation occurs. Communities, Habitats & Niches A community is made up of all the species that live in the same ecosystem at the same time. Habitat The place within an ecosystem where an organism lives is its habitat A habitat provides all the resources an organism needs, including food and shelter. •Forests •Grasslands •Deserts •Tundra Niche An organism’s way of life within an ecosystem Different species have different niches in the same environment How an organism obtains energy is an important part of its niche. Relationships in Communities Competition- 2 or more individuals or populations try to use the same limited resource such as food, water, shelter, or sunlight Can occur within or between populations Relationships in Communities Predators and Prey- interaction when one organism eats another Prey-organism that is eaten • Adaptations to survive- run, stay in groups, camouflage, poisonous Predators- organism that eats the prey • Adaptations to catch prey- fast, camouflage Relationships in Communities A close relationship between two or more organisms of different species that live in direct contact is called symbiosis Individuals can benefit from, be unaffected by, or be harmed Kinds of Symbiosis Mutualism-both organisms benefit from the relationship Ex. Algae produce food for coral, which provides shelter for algae Kinds of Symbiosis Commensalism- one organism benefits and the other is unaffected • Ex. Sharks and Remoras Remoras “hitch a ride” and feed on scraps of food left by sharks; shark is unaffected Kinds of Symbiosis Parasitism-one benefits and the other is harmed Ex. Fleas & ticks on your pet Parasite benefits (ex: ticks, tapeworms) Host is harmed How do humans rely on other organisms? "Treat the earth well: it was not given to you by your parents, it was loaned to you by your children. We do not inherit the Earth from our Ancestors, we borrow it from our children." • Proverb-Ancient Native American • -More quotes about [Ecology] [Interdependence] [Stewardship] [NativeAmerican] -More quotes about [Common Good] [Core Democratic Values] [Ecology] [Interdependence] [Stewardship]