Lesson Overview 3.1 What Is Ecology?

The Science of Ecology Ecology is the scientific study of interactions among and between organisms and their physical environment.

Levels of Organization Population—a group of individuals that belong to the same species and live in the same area and can breed. Community—a group of different populations that live together in a defined area. Ecosystem—all the organisms that live in a place, together with their physical environment (living and non-living factors)

Levels of Organization Biomes—a group of ecosystems that share similar climates and typical organisms

Biotic Factors vs. abiotic… A biotic factor is any living part of the environment with which an organism might interact, including animals, plants, mushrooms (fungi) and bacteria. An abiotic factor is any nonliving part of the environment, such as sunlight, heat, precipitation, humidity, wind or water currents, soil type, etc.

Primary Producers No organism can create energy from scratch —organisms can only use energy from other sources. (Energy is neither created nor destroyed – only RECYCLED!) For most life on Earth, (but not ALL) sunlight is the ultimate energy source. Autotrophs like plants, algae, and bacteria can capture energy from sunlight and turn it in to glucose. Autotrophs are also called primary producers (they PRODUCE the food).

Primary Producers Organisms that eat producers are called consumers. There are 4 levels of consumers (see below). However, the amount of energy that is transferred to each consumer is only 10% of the energy available. Much energy is lost as heat and other processes.

Life Without Light Biologists have discovered thriving ecosystems around volcanic vents in total darkness on the deep ocean floor. Deep-sea ecosystems depend on primary producers that harness chemical energy from the vents like sulfer. The use of chemical energy to produce carbohydrates is called chemosynthesis. http://www.youtube.com/watch?v=SyBO10VhVmc

Types of Consumers Consumers are classified by the ways in which they acquire energy and nutrients. Carnivores kill and eat other animals, and include snakes, dogs, cats. Catching and killing prey can be difficult and requires energy, but meat is rich in nutrients and energy and is easy to digest. Scavengers, like a king vulture, are animals that consume the carcasses of other animals that have been killed by predators or have died of other causes. (Don’t spend energy to eat!)

Decomposers, such as bacteria and fungi, feed by chemically breaking down organic matter. The decay caused by decomposers is part of the process recycles nutrients to the soil so they can be used again.

Types of Consumers cont. Omnivores are animals whose diets naturally include a variety of different foods that usually include both plants and animals. Humans, bears, and pigs are omnivores. Herbivores – eat only plant material in nature. Grazers – deer, cows Detritivores, like giant earthworms, feed on detritus particles, often chewing or grinding them into smaller pieces.

Biological magnification – a pesticide or toxin will increase concentration the further up the food chain you go. DDT (insecticide from the 1970’s) causes bird shells to break! Most pesticides accumulate in fat (adipose) tissue. This happens with Mercury too. The hawk eats many fish and takes in their toxins too. The toxins accumulate over time and show detrimental effects to the top predators!