Ecological Interactions

What is Ecology  Ecology is the interactions between various organisms and their environments.  This includes interactions between living and non living factors.  Great White Shark Video Great White Shark Video  Icy Finger of Death (8 th Grade) Icy Finger of Death (8 th Grade)

Habitat  The place where an organism lives and that provides the things the organism needs is called it’s habitat.  Habitats provide food, water, shelter, and other things needed to grow and reproduce.  A specific type of habitat which has a certain level of rainfall, vegetation, and communities of organisms is known as a biome.  What are some examples of biomes?

Biotic vs. Abiotic  Biotic Factors are the living parts of an ecosystem. They include grass, plants, seeds, and other organisms.  Abiotic Factors are the nonliving parts of an ecosystem. They include things such as water, sunlight, oxygen, soil, and temperature.

Groups in Ecosystems  Species: A group of organisms that are physically similar and can reproduce with each other to produce fertile offspring.  Population: All the members of one species in a particular area.

Groups in Ecosystems  Community: All the different populations that live together in an area.  Ecosystem: The community and abiotic factors in a specific area.

Changes in Population Size  Population can change in size when new members enter the population or when members leave the population.  This can occur due to births, deaths, immigration, and emigration.

Population Cycles  A population cycle shows the population of various organisms over time.  As Predator Populations increase they overuse their resources and prey sizes decrease.  Because there is less prey this causes predator sizes to eventually decrease.  Because predator sizes go down this causes prey sizes to increase.  As you can see this can be an endless cycle!  Ecology Crash Course Video Ecology Crash Course Video

Changes in Population Size

Human Population Graph Human Population Clock

Limiting Factors  Limiting Factors: These factors are things that cause a population to stop increasing or to go down.  What are some examples of limiting factors?  Examples of limiting factors would be things such as water, food, to many predators, oxygen (air), climate (heat/cold), natural disasters, space etc.

Energy Roles in Ecosystems  An organisms energy role in an ecosystem may be that of a producer, consumer, or decomposer.  Most energy is introduced through the sun into the ecosystem.

Producers  Energy first enters most ecosystems as sunlight. Some organisms such as plants, algae, and some bacteria, are able to capture the energy of sunlight and store it as food energy.  An organism that can make its own food is a producer. Producers are the source of all the food in an ecosystem.  Producers are aka as autotrophs. There are 2 types of autotrophs.  Photosynthesis: Using Sunlight + CO2 + H20 = O2 + Sugar (Glucose)

Archaebacteria-Producers  Some Archaebacteria can produce food from gas and hydrogen sulfide.  They are often found in deep sea vents, geysers, or under ground.  Archaebacteria are now part of the Kingdom Monera.

Consumers  Consumers are organisms that obtain energy by feeding on other organisms. (Heterotrophs)  Consumers are classified by what they eat.  Consumers that eat only plants are called herbivores. (Deer and Cattle)  Consumers that eat only animals are called carnivores. (Lions, Spiders, Snakes)  Consumers that eat both plants and animals are called omnivores. (Example: Crows, Humans)  Giant Jellyfish Gets Consumed (8 th Grade) Giant Jellyfish Gets Consumed (8 th Grade)

Cellular Respiration  Most animals perform a process called cellular respiration.  Cellular respiration involves getting energy from food and exchanging oxygen and carbon dioxide with the atmosphere.  Similar to how plants use photosynthesis to get energy we use cellular respiration to get energy from food.

Decomposers  Organisms that break down wastes and dead organisms and return the raw materials to the environment are called decomposers. (Bacteria, Fungi, Mushrooms, Mold)  Decomposers are aka saprotrophs.  Without Decomposers their would be no energy cycle because they return materials such as carbon and nitrogen back to the soil where plants can use them.  Decomposers are also known as saprotrophs which means to “dead matter nourishment.”

Organism Interactions  There are 3 main types of interactions among organisms. They are competition, predation, and symbiosis.

Competition  Different species can share the same habitat. Different species can also share similar food requirements.  For example Lions and Hyenas are both flesh eaters that live in the Serengeti. They must constantly compete for limited resources.  Mudskippers Video Competition Mudskippers Video Competition  Penguin Thieves Penguin Thieves  Giraffe Fights (8th Grade) Giraffe Fights (8th Grade)

Predation  An interaction in which one organism kills and eats another is called predation. The organism that does the killing is the predator. The one that is killed is the prey.  Komodo Dragon Video Komodo Dragon Video  Baby Sea Turtles vs. Predators (8 th Grade) Baby Sea Turtles vs. Predators (8 th Grade)  Bison vs. Wolves (8 th Grade) Bison vs. Wolves (8 th Grade)

Food Chains  A food chain is a series of events in which one organism eats another and obtains energy.  The first organism in a food chain is always a producer, such as the grass in a field.  The second organism is a consumer that eats the producer, and is called a first- level consumer. This first level consumer has to be a herbivore or an omnivore.  A second-level consumer might eat the first-level consumer. (and so on and so on) The second level consumer is usually a carnivore.  In this picture what would happen if all of the caterpillars died off?  Killer Whales and Seals Video 8 th Grade Killer Whales and Seals Video

Food Chain or Food Web  A food chain is a series of events in which one organism eats another and obtains energy.  A food web consists of many overlapping food chains in an ecosystem.  It’s easy to forget that the food chain involves pretty much all organisms big and small in an ecosystem.  Africa Silver Ants Video 8 th Grade Africa Silver Ants Video

Food Web

Symbiosis  Symbiosis is a close relationship between two or more species wherein one of them benefits!

Symbiosis-Mutualism  A relationship in which both species benefit is called mutualism.  At this very moment you are participating in a mutualistic relationship. Bacteria called Escherichia coli in your stomach. They help you digest foods that mammals can not normally digest and you give them a place to live.

Symbiosis Pictures

Symbiosis-Commensalism  Commensalism is a relationship in which one species benefits and the other species is neither helped nor harmed.  Least common type of symbiosis  Red Tailed Hawk can build it’s nest in a cactus. The hawk gets shelter but the cactus gets no benefit.  Commensalism Plant Video Commensalism Plant Video  Symbiosis and Competition Video (NUTS) Symbiosis and Competition Video (NUTS)

Symbiosis-Parasitism  Parasitism involves one organism living on or inside another organism and harming it.  Common parasites are ticks and leeches. These parasites have adaptations that enable them to attach to their host and feed on its blood.  Unlike a predator, a parasite does not usually kill the organism it feeds on.  Bird Parasitism Video 7th Grade Bird Parasitism Video 7th Grade  Parasites in a Caterpillar 8 th Grade Parasites in a Caterpillar 8 th Grade  Ecology Crash Course Video 8 th Grade Ecology Crash Course Video