Ecology The branch of biology that deals with the interactions between organisms and the relationship between organisms and the environment. Many people do not realize that the consequences of their actions can adversely affect other living things and inaction often contributes to many of a community’s problems and to the world problems. Directly and indirectly, we are all involved in making ecological decisions on a daily basis. Introductory Activity How do organisms affect one another's survival? Procedure §         Make a list of all the types of organisms, including plants, humans, insects, and so on, that you have seen near your home or school. §         Make a diagram that shows how the organisms on your list interact with one another. Think About It §         Classifying Which organisms on your list provide energy or nutrients to the others? §         Predicting What would you expect to happen if all the plants on your diagram died? Explain your answer. §         Posing Questions Why is it difficult to make accurate predictions about changes in communities of organisms?  

Why Study Ecology? All things are connected like the blood that unites us’; we did not weave the web of life. We are merely a strand in it. Whatever we do to the web, we do to ourselves. We are part of the earth and the earth is part of us. Chief Seattle

All living organisms depend on the natural world for vital nutrients, water, and shelter. The consequences of our actions adversely affect other living things both directly and indirectly Humans have a greater capacity to alter their environment than other organisms. Easter Island

Includes all the members of a species found in a given area. Population   Includes all the members of a species found in a given area. Ex: waterlillies in a pond Community Includes all the populations in a given area. Ex: all plants, animals, and microorganisms make up a pond community.     Ecosystem Includes all the members of the community plus the physical environment in which they live in. Biosphere The portion of the earth in which life exists. The biosphere is composed of many complex ecosystems that include water, soil, and air.

Use Visuals As class looks at figure above, call on students at random to define term that identifies each level of organization: population, community, ecosystem, biome and bisphere. Then ask: Can a group of rabbits and a group of field mice make up the same population in an ecosystem? (No, because individuals that make up a population must be of the same species) Could a biome in Brazil near the equator be the same as biome northern Canada? Explain (no, because those two biomes would have different climates and different dominant communities)

The structural and functional unit studied in Ecology (I) Ecosystem   The structural and functional unit studied in Ecology (A) Requirements for a Stable Ecosystem 1. The ecosystem involves interactions between living and nonliving things. Certain requirements must be met for a stable ecosystem to exist: 2. There must be a constant supply of energy (sunlight for photosynthesis). 3. There must be living organisms that can incorporate the energy into organic compounds (food). 4. There must be a recycling of materials between organisms and the environment. 5. Biodiversity must exist. This refers to the presence of a wide range of different species of organisms living and interacting with each other and with their nonliving environment

Nonliving factors. B) Abiotic Factors The abiotic factors of an ecosystem include the physical and chemical factors that affect the capacity of an organism to live and reproduce. These factors are: 1. Intensity and duration of light (Ex.: essential for plants) 2. Temperature range 3. Amount of moisture 4. Type of substrate 5. Availability of inorganic substances and gases 6. pH

Determines the types of organisms that may exist in that environment. Limiting Factors Determines the types of organisms that may exist in that environment. Examples are: A low temperature common to northern latitudes determines in part what species of plants can exist in that area. The amount of oxygen dissolved in a body of water will help determine which species of fish will exist there. The amount of food in a given area.

These factors directly or indirectly affect the environment. Carrying Capacity The maximum number of organisms that can be supported by their environment is called the carrying capacity of the environment. Examples are: Human population on Earth. Eventually the earth’s carrying capacity will not be able to support any humans- Examples are Depletion of food, fresh water, and space. (C) Biotic Factors Living factors These factors directly or indirectly affect the environment. Will come back to carrying capacity near the end of this unit After Biotic Factors: Applying Concepts Point out to students that in any ecosystem, removing biotic elements can dramatically affect the ecosystem’s abiotic conditions. Ex: the trees in forest hold topsoil with roots, shade soil, contribute organic matter to soil in form of dead leaves and return water to atmosphere through evaporation and transpiration. Removing trees from forest ecosystem reduces these benefits. Thus, the organisms, their presence, parts, interaction, and wastes all act as biotic factors. These interactions include: Nutritional relationships 2. Symbiotic relationships

Nutritional Relationships Involves the transfer of nutrients from one organism to another within an ecosystem. In terms of nutrition, organisms are either autotrophs or heterotrophs. AUTOTROPHS Using light energy from the sun and inorganic compounds these organisms are able to produce their own food (i.e.: nutrients for energy to perform life functions) Some autotrophs use chemicals such as H2S instead of sunlight.

Ex: mushrooms are saprophytes that feed off dead plants. Types of Heterotrophs 1. Saprophytes - Include heterotrophic plants, fungi, and bacteria, which feed on dead organisms. Ex: mushrooms are saprophytes that feed off dead plants. My favorite – Portobello mushrooms 2. Herbivores- animals that feed on plants. Ex: deer 3. Carnivores- animals that consume other animals Two types: Carnivores Predator – which kills and consume their prey. Scavenger- that feed on the remains of animals they did not kill. 4. Omnivores - Animals that consume both plants and animals (humans).

(II) Energy Flow Relationships For an ecosystem to be self-sustaining, there must be a flow of energy between organisms The pathway of energy flow through the living components of an ecosystem are represented by food chains and food webs. (A) Food Chains Green plants and other photosynthetic organisms are the organisms in an ecosystem that can convert radiant energy from sunlight into food. A food chain involves the transfer of energy from green plants through a series of organisms with repeated stages of eating and being eaten. (B) Food Webs In a natural community, most organisms eat more than one species and may be eaten, in turn, by more than one species. Thus, the various food chains in a community are interconnected forming a food web.

There are three basic classes of organisms in a food web: Each ecosystem has a trophic structure of feeding relationships that determine the paths of energy flow and chemical cycling. Ecologists divide the species in a community or ecosystem into different trophic levels based on their main source of nutrition. 1. Producers Include green plants and other photosynthetic organisms that synthesize the organic nutrients that supply energy to other members in the community.  2 . Consumers Include all heterotrophic organisms. Organisms that feed on green plants are primary consumers, or herbivores. Secondary consumers, or carnivores, feed on other consumers. Tertiary & Quaternary are carnivores that feed on secondary and tertiary consumers respectively. 3. Decomposers Are the organisms (saprophytes) that break down wastes and dead organisms so that chemical materials are returned to the environment for use by other living organisms

The greatest amount of energy in a community is present in the Pyramid of Energy The greatest amount of energy in a community is present in the organisms that make up the producer level Only a small portion of this energy (~10% - The Ten Percent Rule) is passed on to primary consumers, and only a smaller portion is passed on to secondary consumers. Pyramid of energy can be used to illustrate the loss of usable energy at each feeding level (also known as a trophic level).

Pyramid of Numbers

Pyramid of Numbers

(III) Cycle of Materials In a self-sustaining ecosystem, various materials are recycled between organisms and the abiotic environment. The recycling process allows materials to be used over and over again. Three examples are: Carbon-Hydrogen-Oxygen cycle Water cycle Nitrogen cycle Carbon-Hydrogen-Oxygen Cycle Carbon, hydrogen, and oxygen are recycled through the environment by the processes of respiration and photosynthesis.

and by transpiration in plants. Water Cycle Here water moves between the earth’s surface and the atmosphere. Evaporation- liquid water on earth’s surface changes to gas by the process of evaporation and enters the atmosphere in the form of water vapor Condensation- water vapor is returned to liquid state and falls as precipitation. Some water vapor is added to the atmosphere by aerobic respiration in plants and animals and by transpiration in plants.

Nitrogen is needed by all living things because it is part of the Nitrogen Cycle Nitrogen is needed by all living things because it is part of the structure of amino acids and proteins. In this cycle, nitrogenous wastes and the remains of dead organisms are converted by decomposers and soil bacteria into compounds that can be used by autotrophs.

http://www. biology. ualberta http://www.biology.ualberta.ca/facilities/multimedia/uploads/ecology/ncycle.html

Predator – Prey relationships

http://www. youtube. com/watch. v=MksUvwYM_WQhttp://www. youtube http://www.youtube.com/watch?v=MksUvwYM_WQhttp://www.youtube.com/watch?v=MksUvwYM_WQ

Different species living in the same environment or habitat (B) Competition Different species living in the same environment or habitat may require the same resources. When the resources are limited, competition occurs among the species. Competition The struggle between different species for the same limited resources. The more similar the needs of the species, the more intense the competition. Each species occupies a niche in the community. A niche is the role the species plays, and includes the type of food it eats, where it lives, where it reproduces, and its relationships with other species. Most likely, one warbler species would be more successful in that niche, and the other species would not survive.

When two different species compete for the same niche in a community, the weaker species is usually eliminated establishing one species per niche in a community. Graphs showing competition between two species of Paramecium. Since each population alone prospers (top two graphs), when they are in a competition situation one species will win, the other will lose (bottom graph).

http://www.youtube.com/watch?v=dOV0E5FaKoQ Symbiotic Relationships Different organisms may live together in a close association.. This is known as symbiosis. KEY + = benefits -    = harmed 0 = not affected   There are three types: Commensalism (+, o) In this relationship, one organism benefits and the other is not affected. Ex: barnacles on a whale Mutualism (+, +) In this relationship both organisms benefit from each other. Ex: protozoan living in the digestive tract of termites. Wood eaten by termites is digested by the protozoan. The nutrients released supply both organisms Symbiotic Relationships Mutualism—both species benefit (top): The ant cares for the aphids and protects them from predators. The aphids produce a sweet liquid that the ant drinks. Commensalism—one species benefits; the other is neither helped nor harmed (center): The orchid benefits from its perch in the tree as it absorbs water and minerals from rainwater and runoff, but the tree is not affected. Parasitism—one species benefits while the other is harmed (bottom): A flea feeds on the blood of its host, which can be harmed by diseases the flea carries Parasitism (+, -) In this relationship, the parasite benefits at the expense of the host. Ex: athlete’s foot fungus on humans Ex tapeworm and heartworm in dogs. http://www.youtube.com/watch?v=dOV0E5FaKoQ

( IV) Ecosystem Formation Ecosystems tend to change over a long period of time until a stable ecosystem is formed. Both the living and nonliving parts of an ecosystem change.

(A) Ecological Succession - replacement of one kind of community with another. The kind of stable ecosystem that develops in a particular geographical area depends on climate. Pioneer organisms The first plants to populate an area. Lichens and algae may be pioneer organisms on bare rock.

Two Types of Succession Climax Communities Succession ends with the development of a climax community in which the populations of plants and animals exist in balance with each other and the environment. Two Types of Succession Primary (1o) Succession Occurs in an area where there has never been life. Ex.: Newly formed volcanic island

Secondary (2o) Succession Occurs where there once was an ecosystem but either through nature or man, that ecosystem has been destroyed and a new one is appearing. Ex: After a forest fire A former cornfield Typical pioneering organism in an area that once was a cornfield: grasses, annual plants like ragweed, biennials like Queen Anne’s’ lace, annuals like goldenrod, trees like the Quaking Aspen.

A dying pond is another example of secondary succession.

The earth can be divided into broad geographic regions by climate. (C) Biomes The earth can be divided into broad geographic regions by climate. The kind of climax ecosystem that develops in these regions are called biomes. Biomes can be terrestrial or aquatic. Aquatic Biomes Include marine (saltwater) and freshwater) Is a continuous body of water that covers more than 70% of the earth’s surface. Typically more stable than land biomes. The temperature varies less because of the ability of water to absorb and hold heat. Supports a great variety of life forms. Includes the area in which most of the photosynthesis on earth occurs. Ex: Plankton- organisms that float near the surface and are carried by ocean currents. Plankton include protists and algae. These organisms make up the lowest level of the marine food web.

Factors Affecting Water Biomes Amounts of available oxygen and carbon dioxide Temperature and light Amounts of dissolved minerals and suspended particles.

Terrestrial Biomes Tundra Permanently frozen subsoil. Consist of lichens, mosses, and grasses. Examples of animals consist of wolves, caribou and snowy owls.

Summers with thawing subsoil. Taiga Long severe winters. Summers with thawing subsoil. Major plants are conifers. Animals consist of the moose, deer, elk, and black bear.

Moderate precipitation. Temperate Deciduous Moderate precipitation. Cold winters with warm summers. Consist of deciduous trees (Maple, oak, and beech). Animals are gray foxes, bobcats, deer, and raccoons.

Tropical Forest Heavy rainfall, constant warmth. Consist of many species of broad-leaf plants. Some animals are snakes, monkeys, and squirrels. The tropic rainforest has the greatest biodiversity of all the land biomes

Extreme daily temperature fluctuations. Desert Sparse rainfall Extreme daily temperature fluctuations. Plants consist of drought-resistant shrubs and succulent plants. Examples of animals are kangaroo rat, snakes, and lizards.