Ecosystems Study Guide • • • •
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Herbivores o Some animals do not eat other animals. They survive on plants and are known as “herbivores”. Omnivores o Some animals, like us, eat both plants and animals. o These animals are called “omnivores”. Consumers o “Consume” means “eat”. Animals are consumers because they “eat” (consume) food provided by plants or other animals. Producers o Plants are living organisms. They need nourishment to survive. Plants do not eat other plants or animals. Plants are called producers, because they make their own food inside themselves. Predator o A predator eats other animals. o Predator The cat is a predator, because it eats other animals. The bear is a predator, because it eats other animals. People are predators too! Prey o Any animal which is hunted and killed by another animal for food is prey. Food Chains o A food chain shows what is eaten. Food chains always start with a plant. o Food Chains - a Reminder A food chain shows which animals eat other animals or plants. Plants don’t eat things. o A food chain starts with what gets eaten and the arrows point towards what does the eating. o Food chains only go in one direction. Food Webs o In the wild, animals may eat more than one thing, so they belong to more than one food chain. o To get the food they need, small herbivores may eat lots of different plants, and carnivores may eat many different animals. Interactions between Organisms o There are different ways organisms interact with each other such as: Predation Parasitism Mutualism Commensalism o What happens in predation? One organism will eat another. The organism that is eaten is called? • Prey The organism that eats the prey is called? • Predator Examples of Predation Lions hunting zebras Bird hunting worm Polar bear hunting a seal o What is the interaction between predator-prey? Predators eat their prey o What does parasitism mean? One organism feeds on and usually lives on another organism. The organism that’s fed upon is the? • Host The organism that feeds upon the host is the? • Parasite o Parasites Parasites, if in extreme numbers, will kill their hosts by taking away its blood and lowering its immune system. Some parasites are external so they live outside the hosts body. Examples… • Fleas • Leaches • Mosquitoes • Ticks Examples of internal parasites that live inside the host… • Bacteria • Tapeworms • Hookworms An example would be a deer tick and a White-tailed Deer. The tick gets food from the deer without killing it. The deer is harmed by losing blood to the tick, and possibly by getting an infected bite. Also, black fly feed on cattle causing irritation. The cattle exert energy swinging their tails and heads trying to rid their bodies of the flies. o What is the interaction between parasite-host? Parasites feed off of their hosts What is mutualism? Relationship in which organisms from both species benefit from the symbiotic relationship. • In other words, “you scratch my back and I will scratch yours.” Ants and Aphids
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The ants protect the aphids from predators. The aphids secrete a fluid that the ants use for food. Ants provide protection; aphids in return provide food. o The honey bee gets to eat the nectar from the flower. The dandelion uses the bee to spread its pollen to another flower for pollination. o Mutualism: Both Benefit Example: Sea anemones have stinging tentacles. The tentacles are used to capture prey, but clown fish are not hurt by the tentacles’ sting. Clown fish use this to their advantage and live in sea anemones. The anemones provide protection to the clown fish. The clown fish attracts other fish that want to eat it and the anemone catches them with its tenacles. What is commensalism? o Commensalism is a symbiotic relationship in which one organism benefits while the other organism is neither helped nor harmed. Example: an animal using a plant for shelter. • Organism o 1st level of the environment It is a single organism in an environment Example: • A Bee (a single organism) Population o The second level of the environment o Made up of similar organisms o Some Examples: Bees Community o The third level of the environment o Includes: made of different populations in the same area o EXAMPLE: Trees, Birds, Bees, Squirrels Ecosystem o The 4th level o Includes abiotic and biotic o Biotic Trees, Birds, Bees, Squirrels, producer, consumers o Abiotic Rock, Sun, Water, Wind Biosphere o Include all of the ecosystems on Earth! Some examples are: Ocean Ecosystem Desert Ecosystem Freshwater Ecosystem Rain Forest Ecosystem Mountain Ecosystem Pond Ecosystem Competition o Organisms compete for the same food supply and resources. • Biotic o Humans, Animals, Plants • Abiotic o rocks, water, fire, wind, light, temperature, sound, lightning, What is ecology? o Ecology- the scientific study of interactions between organisms and their environments, focusing on energy transfer It is a science of relationships. What do you mean by environment? o The environment is made up of two factors: Biotic factors- all living organisms inhabiting the Earth Abiotic factors- nonliving parts of the environment (i.e. temperature, soil, light, moisture, air currents) Organism- any unicellular or multicellular form exhibiting all of the characteristics of life, an individual. o The lowest level of organization Population-a group of organisms of one species living in the same place at the same time that interbreed and compete with each other for resources (ex. food, mates, shelter). Community- several interacting populations that inhabit a common environment and are interdependent. Ecosystem- populations in a community and the abiotic factors with which they interact (ex. marine, terrestrial). Biosphere- life supporting portions of Earth composed of air, land, fresh water, and salt water. o The highest level of organization Habitat vs. Niche Niche - the role a species plays in a community (job) A niche is determined by the tolerance limitations of an organism, or a limiting factor. o Limiting factor- any biotic or abiotic factor that restricts the existence of organisms in a specific environment. Examples of limiting factors• Amount of water • Amount of food • Temperature Habitat- the place in which an organism lives out its life (address) o Each link in a food chain is known as a trophic level. Trophic levels represent a feeding step in the transfer of energy and matter in an ecosystem. Trophic Levels o RULE OF 10 Only 10% of energy is transferred from one trophic level to the next. • Example: It takes 100 kgs of plant materials (producers) to support 10 kgs of herbivores. It takes 10 kgs of herbivores to support 1 kg of 1st level predator