Published on January 1, 2008
Ch. 24 – Interactions of Life: Ch. 24 – Interactions of Life Sec. 3 – Interactions within Communities 7th Grade Science Saint Objectives: Objectives Describe how organisms obtain energy for life. Explain how organisms interact. Recognize that every organism occupies a niche. Energy: Energy Living organisms need a constant supply of energy. Energy: Energy All of Earth’s energy comes from the Sun. Photosynthesis: Photosynthesis Some organisms use the Sun’s energy to create energy rich molecules through a process called photosynthesis. Product of Photosynthesis: Product of Photosynthesis Energy rich molecules, usually sugars, serve as food. They are made up of oxygen, hydrogen, and carbon atoms. Energy is stored in the chemical bonds of the atoms. When the bond is broken, energy is released to fuel life processes. Photosynthesis: Photosynthesis Producers: Producers A producer is an organism that uses an outside energy source like the Sun to make energy-rich molecules. Producers contain chlorophyll: Producers contain chlorophyll Most producers contain chlorophyll, a chemical that is required for photosynthesis. Green Plants: Green Plants Green plants are producers Chemosynthesis: Chemosynthesis Some producers make energy-rich molecules through a process called chemosynthesis. These organisms are found near volcanic vents in the ocean floor. Inorganic molecules in the water provide the energy source for chemosynthesis. Hydrothermal Vents: Hydrothermal Vents Tubeworms: Tubeworms Consumer: Consumer A consumer is an organism that cannot make their own energy-rich molecules. Consumers obtain energy by eating other organisms. Wolves can’t make their own food. They are consumers. The Cape Buffalo can’t make its own food. It is a consumer. Producer or Consumer?: Producer or Consumer? Tree Dandelion Weasel Walrus Diatom Algae Bacteria Dog You Rhinoceros Consumers: Consumers There are 4 general types of consumers: Herbivores Carnivores Omnivores Decomposers Herbivores: Herbivores Herbivores – Plant eaters Deer Rabbits Grasshoppers Herbivores: Herbivores Zebras eat grass. They are herbivores. Cows are herbivores. Herbivores: Herbivores Hippos are herbivores. Rhinos are herbivores. Carnivores: Carnivores Carnivores – Meat Eaters – Eat other animals Frogs Spiders Cougars Carnivores: Carnivores Lions definitely eat meat! Not all carnivores have razor sharp teeth. The Most Vicious Carnivore: The Most Vicious Carnivore The Shrew Omnivores: Omnivores Omnivores – Eat both plants and animals Bears Pigs Humans Omnivores: Omnivores While the panda’s digestive system is that of a carnivore, their diet consists of 99% bamboo. Raccoons are omnivores. They eat both plants and animals. Decomposers: Decomposers Decomposers – Consume waste and dead organisms. Decomposers help recycle once-living matter by breaking it down into simple, energy-rich substances. These substances might serve as food for decomposers , be absorbed by plant roots, or be consumed by other organisms. Fungi Bacteria Earthworms Vultures Decomposers: Decomposers Mushrooms and other fungi break-down dead decaying matter. What type of consumer?: What type of consumer? Elk Bobcat Mushroom Buzzard Bear Hippopotamus Box Turtle Snapping Turtle Shark Seal Food Chain: Food Chain A food chain is a simple model of the feeding relationship in an ecosystem. Food Chain: Food Chain For example, shrubs are food for deer, and deer are food for mountain lions. Shrubs are the beginning of the food chain. They receive their energy from sunlight. Because shrubs make their own food through photosynthesis, they are called producers. The deer is the first organism of the food chain to eat the shrub. It is the primary consumer. The mountain lion is the second organism of the food chain. It eats the deer. It is the secondary consumer. Food Chain: Food Chain Algae make their own food from sunlight. They are the basis for the food chain in this example. Food Chain: Food Chain The first organism in a food chain is always a producer. They make their own food. Food Chain: Food Chain Food Chain: Food Chain Food Chain: Food Chain Food Chain: Food Chain Food Chain: Food Chain Food Chain: Food Chain Food Chain: Food Chain Food Chain: Food Chain Food Chain: Food Chain Food Chain: Food Chain Symbiosis: Symbiosis Not all relationships among organisms involve food. Many organisms live together and share resources in other ways. Any close relationship between species is called symbiosis. 3 Types of Symbiosis: 3 Types of Symbiosis Mutualism Commensalism Parasitism Mutualism: Mutualism Mutualism – A symbiotic relationship in which both species benefit. Mutualism: Mutualism Examples: Cowbirds and Large Animals Termites and Trichonympha Bees and Flowers Cowbirds and Large Animals: Cowbirds and Large Animals The cowbird benefits by eating the ticks and mites off the large animal. The large animal benefits from have the parasites removed from them. The birds can also warn them of danger. Termites and Trichonympha: Termites and Trichonympha You probably think termites eat wood; they do – in a way. Termites can’t digest cellulose, which is the main component of wood. Therefore, they get help from a protozoan called trichonympha. This protozoan lives in the gut of the termite. It breaks down the cellulose for the termite. The trichonympha gets a free meal and shelter; the termite is able to eat and receive nutrients from the wood. Termite and Trichonympha: Termite and Trichonympha Termite and Trichonympha: Termite and Trichonympha Termite and Trichonympha: Termite and Trichonympha Termite and Trichonympha: Termite and Trichonympha Trichonympha: Trichonympha Trichonympha: Trichonympha Bees and Pollen: Bees and Pollen Bees receive nectar from the flowers in order to make honey. As the bees collect nectar, they collect pollen on their body. As they fly to another flower, they pollinate it by dusting the pollen on the flowers stamen. Commensalism : Commensalism Commensalism – A symbiotic relationship in which one organism benefits and the other is not affected. Commensalism: Commensalism Examples: Clown fish and sea anemones Shark and remora Clown Fish and Sea Anemones: Clown Fish and Sea Anemones The clown fish is immune to the stings of the sea anemones tentacles. The clown fish makes its home in the tentacles for protection. The clown fish gets shelter, but the sea anemone gets nothing. Shark and Remora: Shark and Remora The remora hangs around the shark picking up any scraps it may leave. The remora gets food while the shark gets nothing. Parasitism: Parasitism Parasitism – A symbiotic relationship in which one organism benefits but the other is harmed. Parasitism: Parasitism Examples: Tapeworm and Humans Cuckoo bird and warbler Ticks Tapeworm and Humans: Tapeworm and Humans Tapeworms and Humans: Tapeworms and Humans Tapeworms and Humans: Tapeworms and Humans Tapeworms and Humans: Tapeworms and Humans Cuckoo and Warbler: Cuckoo and Warbler Cuckoo birds and warblers: Cuckoo birds and warblers Cuckoo and Warbler: Cuckoo and Warbler Cuckoo and Warbler: Cuckoo and Warbler Ticks: Ticks Tick : Tick Even Athletes foot is a parasite: Even Athletes foot is a parasite Parasitism: Parasitism Parasitism: Parasitism Symbiosis: Symbiosis Habitat: Habitat One habitat might contain hundreds or even thousands of species. A rotting log in a forest can be home to many species of insects, including termites that eat decaying wood and ants that feed on the termites. Other species that live on and under rotting log include millipedes, centipedes, spiders, and worms. Niche: Niche You might think that competition for resources would make it impossible for so many species to live in the same habitat. However, each species has different requirements for its survival. As a result, each species has its own niche. An organism’s niche is its role in its environment – how it obtains food and shelter, finds a mate, cares for its young, and avoids danger. Niche: Niche Predator and Prey: Predator and Prey An organism’s niche includes how it avoids being eaten and how it finds or captures its food. Predators are consumers that capture and eat other consumers. The prey is the organism that is captured by the predator. Predator and Prey : Predator and Prey The deer is being eaten by the python. It is prey. The python has captured and is eating the deer. Predator and Prey: Predator and Prey Predator Prey Predator and Prey: Predator and Prey Predator Prey Predator and Prey: Predator and Prey Prey Predator Predator and Prey: Predator and Prey This alligator is the predator. It eats the python. This python is the prey. It is eaten by the alligator. Predator and Prey: Predator and Prey This python swallowed the alligator. It is the predator. This alligator was swallowed by the python. It was the prey. The alligator did get some revenge. The meal was too big for the python and caused it bust. Lynx vs. Hare: Lynx vs. Hare Predator/Prey Relationship : Predator/Prey Relationship Predator/Prey Relationship: Predator/Prey Relationship Predator/Prey Relationship: Predator/Prey Relationship Cooperation: Cooperation Individual organisms often cooperate in ways that improve survival. Whitetail Deer Cooperation: Whitetail Deer Cooperation Whitetail Deer – Whitetail deer will lift their tail to alert others when they feel threatened. Ants and Honeybees: Ants and Honeybees Ants and honeybees live in social groups. Certain individuals have specific jobs within the colony. Soldiers – Protection of colony Workers – gather food and take care of young (larva) Cooperation: Cooperation These cooperative actions improve survival and are a part of the specie’s niche. Section Summary: Section Summary All life requires a constant supply of energy. Section Summary: Section Summary Most producers make food by photosynthesis using light energy. Section Summary: Section Summary Consumers cannot make food. They obtain energy by eating producers and other consumers. Section Summary: Section Summary A food chain models the feeding relationships between species. Section Summary: Section Summary Symbiosis is any close relationship between species. Section Summary: Section Summary Mutualism, commensalism, and parasitism are types of symbiosis. Section Summary: Section Summary An organism’s niche describes the ways in which the organism obtains food, avoids danger, and finds shelter. Question: Question 1. Explain why all consumers depends on producers for food. Question: Question 2. Describe a mutualistic relationship between two imaginary organisms. Name the organisms and explain how each benefits. Question: Question 3. Compare and contrast the terms habitat and niche. Question: Question 4. A parasite can obtain food only from a host organism. Explain why most parasites weaken, but do not kill, their hosts.