Fungi Symbiosis ( Read ) | Biology | CK Foundation
Mapping ecosystems Plant organisation . The feeding relationships between these groups can be shown in food . An example of an ectoparasite is the fungus that causes tinea or athlete's Proposed idea that weight gained. Discusses parasitic and mutualistic relationships of fungi. Do all fungi feed only on dead organisms? Not all. This fungus is a lichen. The idea of the web of life is shown by the interdependence within an ecosystem. Animals and plants depend on a complex system of food for survival. When an animal dies, it is decomposed by worms, fungi and bacteria action and Have students map the area by observing and identifying animals (insects, birds, signs) .
Students will understand that interrelating communities are components of an ecosystem. Activities Demonstrate the concept of interdependence to students by setting up a row of dominos with enough space between one section that will allow a chain reaction to stop at that point after the first has been pushed.
Every block removed causes a change in the structure--some reactions are more severe than others; for instance, if a bottom or center block are pulled, the system collapses. Go outside and mark off a large area.
A field with diverse vegetation is best. Divide the area into sections using a measuring tape. Have students map the area by observing and identifying animals insects, birds, signs and noting their location. Compare the different animals by their locations.
Lesson 4: Food Chains
Group students into teams. Go outside and identify distinctly different vegetative areas, such as a lawn, woods, and open field, marsh, or a pond. Assign a team to each area or ecosystem.
Using sweep nets, dip nets, magnifying lenses, egg cartons, trowels, pans and plastic bags, collect plant and insect specimens from each area.
Minimize the impact by keeping animals live and taking only parts of plants, such as a leaf. Record or draw pictures of plants or animals that are not collectible. After collecting samples and data, regroup for comparison of the areas. A food web depicts a collection of polyphagous heterotrophic consumers that network and cycle the flow of energy and nutrients from a productive base of self-feeding autotrophs.
Feeding connections in the web are called trophic links. The number of trophic links per consumer is a measure of food web connectance. Food chains are nested within the trophic links of food webs. Food chains are linear noncyclic feeding pathways that trace monophagous consumers from a base species up to the top consumerwhich is usually a larger predatory carnivore.
Trophic species are functional groups that have the same predators and prey in a food web. Common examples of an aggregated node in a food web might include parasitesmicrobes, decomposerssaprotrophsconsumersor predatorseach containing many species in a web that can otherwise be connected to other trophic species. Trophic level A trophic pyramid a and a simplified community food web b illustrating ecological relations among creatures that are typical of a northern Boreal terrestrial ecosystem.
The trophic pyramid roughly represents the biomass usually measured as total dry-weight at each level. Plants generally have the greatest biomass.
Names of trophic categories are shown to the right of the pyramid. Some ecosystems, such as many wetlands, do not organize as a strict pyramid, because aquatic plants are not as productive as long-lived terrestrial plants such as trees.
Ecological trophic pyramids are typically one of three kinds: Basal species, such as plants, form the first level and are the resource limited species that feed on no other living creature in the web. Basal species can be autotrophs or detritivoresincluding "decomposing organic material and its associated microorganisms which we defined as detritus, micro-inorganic material and associated microorganisms MIPand vascular plant material.
The top level has top or apex predators which no other species kills directly for its food resource needs. The intermediate levels are filled with omnivores that feed on more than one trophic level and cause energy to flow through a number of food pathways starting from a basal species.
The trophic level is equal to one more than the chain length, which is the number of links connecting to the base. The base of the food chain primary producers or detritivores is set at zero.
The technique has been improved through the use of stable isotopes to better trace energy flow through the web. This realization has made trophic classifications more complex. The basis of trophic dynamics is the transfer of energy from one part of the ecosystem to another. Omnivores, for example, are not restricted to any single level. Nonetheless, recent research has found that discrete trophic levels do exist, but "above the herbivore trophic level, food webs are better characterized as a tangled web of omnivores.
Ecologists use simplified one trophic position food chain models producer, carnivore, decomposer.
Using these models, ecologists have tested various types of ecological control mechanisms. For example, herbivores generally have an abundance of vegetative resources, which meant that their populations were largely controlled or regulated by predators.
Natural Resources, the Environment and Ecosystems
This is known as the top-down hypothesis or 'green-world' hypothesis. Alternatively to the top-down hypothesis, not all plant material is edible and the nutritional quality or antiherbivore defenses of plants structural and chemical suggests a bottom-up form of regulation or control.
Links in a food-web illustrate direct trophic relations among species, but there are also indirect effects that can alter the abundance, distribution, or biomass in the trophic levels. For example, predators eating herbivores indirectly influence the control and regulation of primary production in plants.
Although the predators do not eat the plants directly, they regulate the population of herbivores that are directly linked to plant trophism. The net effect of direct and indirect relations is called trophic cascades. Trophic cascades are separated into species-level cascades, where only a subset of the food-web dynamic is impacted by a change in population numbers, and community-level cascades, where a change in population numbers has a dramatic effect on the entire food-web, such as the distribution of plant biomass.
The Web of Life
Ecological efficiency The Law of Conservation of Mass dates from Antoine Lavoisier's discovery that mass is neither created nor destroyed in chemical reactions. In other words, the mass of any one element at the beginning of a reaction will equal the mass of that element at the end of the reaction. Keep going through the chain until you get to the top consumers. The string will be a tangled web in the middle of the circle.
Food chains are complicated, and the balance they create is essential. For example, the impact of overhunting will cause the lions to drop their strings. Possible Questions Do you know why there are more herbivores than carnivores? What if one animal from the food chain disappeared?
What about one level of the food chain? How do humans fit in the food chain? What could happen if an animal not native to an area is brought into the local food chain? What could happen if you remove an animal from the food chain? How can sun and rain affect the food chain? Why is a food web a more accurate depiction of nature than a food chain or pyramid? Food Chain Tag This activity requires a large open area.
In a class of 25 to 40 students, choose three to five to be predators and seven to ten to be plant-eaters. The remainder will be plants. This represents a balanced system where plants are more plentiful than plant-eaters, plant-eaters more plentiful than predators, and predators are the least plentiful.