Lecture on Omnivores www assignmentpoint com Omnivores Omnivores

Lecture on Omnivores www. assignmentpoint. com

Omnivores • Omnivores eat plants, but not all kinds of plants. • Omnivores can't digest some of the substances in grains or other plants that do not produce fruit. • They can eat fruits and vegetables, though. Some of the insect omnivores in this simulation are pollinators, which are very important to the life cycle of some kinds of plants. Large Omnivores www. assignmentpoint. com

Omnivores www. assignmentpoint. com

Omnivores • Some animals don’t fit neatly into a single category because they have wider tastes. These animals, that feed on a combination of plants and animals, are called Omnivores. www. assignmentpoint. com

Symbiosis Most of the interactions between species involve food: • competing for the same food supply • eating (predation) • avoiding being eaten (avoiding predation) www. assignmentpoint. com

Symbiosis In symbiosis, at least one member of the pair benefits from the relationship. The other member may be • injured = parasitism • relatively unaffected ( = commensalism) • may also benefit ( = mutualism). www. assignmentpoint. com

Symbiosis Mutualism • Symbiotic relationships in which each species benefits are mutualistic. There are hundreds of examples of mutualism between a heterotroph and an alga. www. assignmentpoint. com

Symbiosis • Paramecium bursaria is a ciliate that engulfs unicellular green algae into vacuoles within its cell. – The paramecium certainly benefits from the food synthesized by the alga. It can be cultured apart from the alga but then must be given extra food. – The alga presumably benefits from the carbon dioxide produced by its host as well as the host's ability to transport it to a spot where there is ample light. www. assignmentpoint. com

Symbiosis • Many other aquatic heterotrophs – sponges – sea anemones – planarians – clams • also harbor algae within their cells. www. assignmentpoint. com

Symbiosis • liberating toxins, for example, – Tetanus bacilli secrete tetanus toxin which interferes with synaptic transmission. – Diphtheria bacilli secrete a toxin that inhibits protein synthesis by ribosomes. • The relationship between parasite and host varies along a spectrum that extends from www. assignmentpoint. com

Symbiosis • Mutualistic relations between plants and fungi are very common. The fungus invades and lives in or among the cortex cells of the secondary roots. The association is called a mycorrhiza. www. assignmentpoint. com

Symbiosis • The fungus helps the host plant absorb inorganic nitrogen and phosphorus from the soil. Some mycorrhizal fungi also secrete antibiotics which may help protect their host from invasion by parasitic fungi and bacteria. www. assignmentpoint. com

Symbiosis • Many mushrooms are the spore-forming bodies of mycorrhizal fungi. The truffle [View] is often found in oak forests because the fungus that produces it establishes mycorrhiza on oak roots. www. assignmentpoint. com

Symbiosis Parasitism • A parasite is an organism that • lives on or in the body of another organism (the host) • from whose tissues it gets its nourishment, and • to whom it does some damage www. assignmentpoint. com

Symbiosis • "hit and run" parasites that live in their host for a brief period and then move on to another with or without killing the first to • parasites that establish chronic infections. Both parasite and host must evolve to ensure the survival of both because if the parasite kills its host before it can move on, it destroys its own meal ticket. • Link to further discussion. www. assignmentpoint. com

Symbiosis • Animals are parasitized by viruses, bacteria, fungi, protozoans, flatworms (tapeworms and flukes), nematodes, insects (fleas, lice), and arachnids (mites). • Plants are parasitized by viruses, bacteria, fungi, nematodes, and a few other plants. • Parasites damage their host in two major ways: • consuming its tissues, e. g. , hookworms www. assignmentpoint. com