Ecological Interactions

What is Ecology Ecology is the interactions between various organisms and their environments. This includes interactions between living and non living factors.

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.

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.

Changes in Population Size Populations can often change due to limiting factors. A limiting factor is an environmental factor that prevents a population from increasing. Some limiting factors for populations are food, space, and weather conditions.

Natural Selection The changes that make organisms better suited to their environments develop through a process called Natural Selection. Individuals in a population have different characteristics. Those individuals whose characteristics are best suited for their environment tend to survive and produce offspring.

Natural Selection Continued… Over many generations individuals with those characteristics continue to reproduce. Individuals that are poorly suited to the environment are less likely to survive and reproduce. This process results in adaptations, the behaviors and physical characteristics of species allow them to successfully live in their environments.

Adaptations Every organisms has a variety of adaptations that are suited to its specific living conditions. The organisms particular roles or how it makes its living, is called its niche. Frozen Frogs

Peppered Moth Story Back around 1850 in England there existed two different types of moths that came in light and dark forms. Pollution from the Industrial Revolution darkened the tree trunks where the moths inhabited.

Peppered Moth Story The lighter moths which used to be well camouflaged were now easily seen by birds that would eat them. The dark colored moths now had a characteristic which helped them survive in their environment because they could not be seen on the dark tree trunks.

Is Being Dark Always an Advantage for Moths It’s important to realize that an adaptation is not always beneficial in every environment. Can you think of an environment where it would not be beneficial to be a dark colored moth?

Galapagos Finches The Galapagos Islands are a group of islands located off the coast of South America. There are different dominant bird species on almost every island. Why? The food available on each island differs in size. The bird with the beak best suited to eat the food usually survives.

Galapagos Finches Some beaks are advantageous to have on certain islands but not others. Organisms that are able to eat usually are able to grow up and reproduce. This is Survival of the Fittest.

How do we use genetics to benefit us? Dairy Farmers sometimes only breed the cows that produce the best milk. Over time the milk product is better because only the best cows are reproducing.

How do animal in nature use this? Some insects use mimicry to make themselves look like a dangerous creature, even though they are really not. Example: The picture to the right is not a wasp. It is actually a moth. Some people call it a hornet moth because of it’s appearance. Animals such as this that are naturally different can use this as an advantage and survive. Insects can not decide when to use mimicry but if they naturally have traits that help them survive they will pass them on to their offspring.

Organs Structures The structure of an organisms organs can often help it survive in a specific environment. Birds have hollow bones which allow them to fly in air. Dense root structures allow plants to grow in compact arid soil.

Inherited vs. Acquired All of these characteristics we have discussed are inherited. That means they are passed on from parent to offspring. Acquired characteristics are just the opposite. They are acquired during the life of the organism and not passed on to their offspring. Just because your Dad was really good at football doesn’t mean you will be. He acquired that trait.

Inherited vs. Acquired Examples of Inherited Characteristics could be: Eye Color, Hair Color, Height, Color Blindness, Diseases, Face Shape, being Bald, etc. Examples of Acquired Characteristics could be: Sports Skills, Education, Muscle Mass, etc.

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.

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.

Predator Adaptations Predators have adaptations that help them catch and kill their prey. For example a cheetah can run very fast for a short time, enabling it to catch its prey.

Prey Adaptations Remember the Peppered Moth. That is an example of prey adaptations. Other examples are protective coverings such as the quills a porcupine has.

Population Cycles 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!

Symbiosis Symbiosis is a close relationship between two species that benefits at least one of the species.

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.

Mutualism 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.

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.

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. 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. Consumers are classified by what they eat. (Cattle, Deer) Consumers that eat only plants are called herbivores. Consumers that eat only animals are called carnivores. (Lions, Spiders, Snakes) Consumers that eat both plants and animals are called omnivores. (Example: Crows, Goats, Humans)

Decomposers Organisms that break down wastes and dead organisms and return the raw materials to the environment are called decomposers. (Bacteria, Fungi, Mushrooms, Mold) 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)