Principles of Ecology

Ecologists study environments at different levels of organization Over their life cycle, Pacific salmon are the main food source for more than 140 species of wildlife, including grizzly bears. Pacific salmon are threatened with extinction due to competition from hatchery fish, blocked river paths, and loss of spawning grounds.

What is ecology? Ecology is the study of the interactions among living things, and between living things and their surroundings.

Relationships The relationships between organisms is sometimes very difficult to decipher.

The Polar Bear and the Sled Dogs

The Polar Bear and the Sled Dogs

The Polar Bear and the Sled Dogs

The Polar Bear and the Sled Dogs

The Polar Bear and the Sled Dog

The Lioness and the Baby Oryx

The Lioness and the Baby Onyx

The Lioness and the Baby Onyx

The Lioness and the Baby Onyx

The Lioness and the Baby Onyx

Interaction?

Interaction?

Interaction?

Interaction?

Levels of Organization

Ecological research methods Observation Observation is the act of carefully watching something over time. Surveys Direct surveys – for easy to follow organisms. Scientist can watch animals with the naked eye or with binoculars or scopes. Indirect surveys—for difficult to track organisms. Scientists search for signs of its presence, such as feces or a recent kill. Long-eared Jerboa

Ecological research methods Experimentation Experiments may be performed in the lab or in the field. This study focuses on small ecosystems. Moss provides structure and ultimately detritus that feeds bacteria, fungus, and other microorganisms at the base of a complex food-web including mites and microarthropods. This has been used as a successful model system to study questions relating to habitat fragmentation and patterns of biodiversity.

Ecological research methods Modeling Using computer and mathematical models to describe and model nature. Used to test hypothetical situations with the use of real data. http://www.pbs.org/wgbh/evolution/sex/guppy/index.html

Biotic and Abiotic Factors

An ecosystem includes both biotic and abiotic factors. Factors that are living things, such as plants, animals, fungi, and bacteria. Abiotic Factors that are non-living things such as moisture, temperature, wind, sunlight, and soil. The balance of these factors determines which living things can survive in a particular environment.

Abiotic or Biotic?

Biotic or Abiotic?

Biotic or Abiotic?

Biotic or Abiotic?

Biotic or Abiotic?

Biotic or Abiotic?

Changing one factor in an ecosystem can affect many other factors. All species are affected by changes to the biotic and abiotic factors in an ecosystem.

The Harbor Seals of California Diatoms Red Tide

The Harbor Seals of California Harbor seals live along the coast of California (among other places). They eat many types of fish, including shell fish.

The Harbor Seals of California As harbor seals eat shell fish that have accumulated toxins, they get domoic acid poisoning. The domoic acid causes severe neurological deterioration. Seals will have nausea, vomiting, abdominal cramps, dizziness, confusion, disorientations, memory loss, motor weakness, seizures, respiratory secretions, cardiac arrhythmia, coma, and death if untreated.

Biodiversity Biodiversity is the assortment, or variety, of living things in an ecosystem. An area with a high level of biodiversity, such as a rain forest, has a large assortment of different species living near one another. The amount of biodiversity found in an area depends on many factors.

Keystone Species In some cases, the loss of a single species may cause a ripple effect felt across an entire ecosystem. These organisms are called keystone species. Keystone species have an unusually large effect on its ecosystem. Prairie dogs are keystone species.

The Sea Otter Sea otters are native to the coasts of the northern and eastern North Pacific Ocean. They are the largest member of the weasel family at 30-100 lbs. Sea otters prey mostly on marine invertebrates, like sea urchins, mollusks, and crustaceans.

Between 1741 and 1911, sea otter were hunted for their fur. The Sea Otter Sea urchins graze on the lower stems of kelp, causing the kelp to drift away and die. Between 1741 and 1911, sea otter were hunted for their fur.

The Sea otter The hunting of sea otters was banned in 1911, and extensive conservation efforts have seen the Sea Otter return to two-thirds of its original habitat and population. Aside from helping kelp forests, and the organisms that rely on them thrive, sea otters also remove mussels from rocks, liberating space for competitive species, thereby increasing the diversity of species in the area.