Introduction to Ecology Ms. Schultz Biology

Ecology is the study of interactions among organisms and between organisms and their surroundings.

Ecologists ask questions at several levels: Species: Organisms so similar to each other that they breed and have fertile offspring. Population: The same species, in the same place, at the same time. Community: All the different species in an area. Ecosystem: All the living and non-living parts of a particular place. Biotic: Living factors such as trees, frogs, bacteria, birds. Abiotic: Non-living factors such as temperature, wind, sunlight, water, fires. Biomes: Groups of ecosystems that have similar climates and communities. Biosphere: Portion of the planet in which all life exists including land, water, and air.

Zedonk

Liger

Wolphin

Zorse

Species

Population

Community – all the living organisms you see.

Ecosystem – all the living organisms you see and the non-living factors like sun, water, oxygen gas, etc.

Biomes – like rainforests, deciduous forests, and deserts

Biosphere

II. Ecosystems change as communities are replaced by other communities. Primary Succession: Occurs where life has never been (bare rock) Pioneer Species (like lichens) come in first to stabilize and enrich the soil. They are followed by plants with greater nutritional needs.

Lichen

II. Ecosystems change as communities are replaced by other communities. Secondary Succession: Occurs where life has been disrupted (storms, mowing lawns, abandoned fields)

II. Ecosystems change as communities are replaced by other communities. A climax community is an ecosystem that remains pretty much the same year after year.

III. Organisms can be categorized by their needs and how they obtain energy. The sun is the primary source of energy for life on earth. Of all the sun’s energy that hits the earth, only about 1% is used by living things.

Autotrophs (producers) can use the energy from the sun to make their own food out of inorganic materials in a process called photosynthesis. Carbon Dioxide + Water → Sugar + Oxygen

Examples of autotrophs include plants, algae, and some bacteria. These organisms are special because they can take light energy and convert it to chemical energy. All living things need chemical energy to survive and maintain organization.

There are also chemosynthetic bacteria that don’t need light to make their food. They use the energy in chemical bonds. They are found in the deep sea and in hot springs.

Heterotrophs (consumers) cannot use energy directly from the physical environment. They must get their energy from other organisms.

Types of Heterotrophs Herbivores (cows, deer) get their energy from eating plants. Carnivores (snakes, wolves) get their energy from eating animals. Omnivores (humans, bears) get their energy from eating plants and animals. Scavengers (crabs, vultures) get their energy from eating animal remains. Decomposers (fungi, bacteria) get their energy from breaking down dead organic matter.

IV. Categories of organisms interact in feeding relationships. Food chains show how energy is transferred by what organisms are eating. The arrow indicates which way energy is moving. What gets eaten → What does the eating

Energy Vs. Matter Energy flow is one way. Energy is either used by the organism or lost as heat. Matter recycles. When an organism dies, its matter can be reused by other organisms to grow.

Food webs show all the feeding relationships in a community.

Give one food chain in the food web to the left. How is a producer different than a consumer? Who is/are the producer/consumers in the food web above? How is the flow of energy in a food web different from that of matter? Use the following words to fill in the blank: ecosystem, population, community. All the rabbits in this food web make up a(n) All the organisms in this food web make up a(n) All the organisms in this food web and the abiotic factors make up a(n) Where would a decomposer feed in this food web? Plant→ Rabbit→ Fox Producers can make their own food whereas consumers must eat. The producers are the plants. The consumers are everything else. Energy flows one way. Matter recycles. Population Community Ecosystem Decomposers would use all of these organisms as a food source.

V. Organisms feed at different levels called Trophic Levels. 1 st trophic level 2 nd trophic level 3 rd trophic level 4 th trophic level Grass → Insect → Lizard → Snake Producer Primary Secondary Tertiary consumer consumer consumer

VI. The amount of energy or matter in an ecosystem can be represented by an ecological pyramid.

Energy Pyramid: Shows how much energy is available at each level.

Biomass Pyramid: Shows how much living tissue is needed at each level. Grass 20,000,000 kg Hare 19,500 kg Fox 9,000 kg Wolf 420 kg

Numbers Pyramid: Shows how many of each organism are needed at each level.

The 10% Rule Only 10 percent of energy is available to organisms in the next trophic level. Why not 100%? Because the organism that will be eaten has used some of that energy to grow and to maintain homeostasis and some of its energy has been lost as heat.

You Try Take this food chain and turn it into an energy pyramid. Algae → Zooplankton → Fish → Heron Label the trophic levels and whether the organism is a producer, a primary consumer, a secondary consumer, or a tertiary consumer. If there are 1000 kcal of energy at the producer level, how much is available at the other trophic levels? Algae Zooplankton Fish Heron 1 st Trophic Level Producer 2 nd Trophic Level Primary Consumer 3 rd Trophic Level Secondary Consumer 4 th Trophic Level Tertiary Consumer Algae1000 kcal Zooplankton100 kcal Fish10 kcal Heron1 kcal