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 Icy Finger of Death (8th

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

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 (8th

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

Penguin Thieves

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

Baby Sea Turtles vs. Predators (8th Grade)

Bison vs. Wolves (8th 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 8th Grade

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 8th Grade

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

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

Parasites in a Caterpillar 8th Grade

Ecology Crash Course Video 8th Grade