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Section 20-1 Species Interactions. Species Interactions. Various species within a community interact with each other in both positive and negative ways. One species might rely on another one for food, reproduction or nutrient cycling .
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Species Interactions Various species within a community interact with each other in both positive and negative ways. One species might rely on another one for food, reproduction or nutrient cycling. One species might be necessary to provide food, habitat spaceor other resources.
Predation In a predation relationship the predator benefits by eating all or part of the prey species which is then harmed. Predation acts as a way to regulate sizes of both species populations. Predators can be either carnivores, herbivores or omnivoresthat may consume a few select species or a wide variety of species.
Predation Predators have adaptations that allow them to better hunt prey such as heightened senses particularly those of smell, vision and heat detection. Predators can have mouthparts designed for capturing and/or chewing their food. Predators may also have attributes like speed, intelligence and/or behavior strategies that assist in obtaining food.
Predation Prey species have evolved adaptations to avoid capture including speed, camouflage or warning coloration. Animals can use mimicry to copy another animal that is poisonous of otherwise dangerous so predators learn to avoid them. Plants utilize strategies such as thorns, tough leaves or chemicals such as nicotine or ivy alkaloids.
Competition In a competition relationship both speciesare harmed. This is because each one uses up energyfighting to get resources. Competition often results when populations sizes increase and resources become limited. Interspecific competition occurs between two or more species while intraspecific competition occurs within a population of one species.
Competition Species cannot compete for a resource indefinitely without conflict. The principle of competitive exclusionstates that two species cannot occupy the same niche because one species will use the limited resource more efficiently then the other one. A species that gets outcompeted has a realized niche that is smaller than its fundamental niche.
Competition It is in the best interest of both species to reduce competition. One way is by character displacement which allows similar species to evolve unique traits that exploit different parts of the niche. Another way is by resource partitioning which allows competing species to divide the niche in either time or space.
Symbiosis Symbiosis is a close, long-term relationship between two species that is often the result of coevolution. Evidence on a cellular level is seen in the endosymbiosis theory of eukaryotic cell development. It is believed that larger prokaryotic cells engulfed smaller aerobic or photosynthetic cells which evolved into energy harvesting organelles.
Parasitism In a parasitic relationship the parasite benefits by exploiting a specific host species which is harmed. Parasites may use their host to obtain nutrients and/or to provide a form of shelter. Parasitism differs from predation because the goal of the parasite is to keep its host alive so that it doesn’t have to find another one.
Parasitism Ectoparasites are ones that live outside of the hosts body and are adapted to attach and obtain nourshment. They can feed on the epidermis cells of skin or leaves or use sucking mouthparts to draw out blood or sap. Ectoparasites can cause damage beyond the feeding effects because they often serve as vectors and can transmit diseases while feeding.
Parasitism Endoparasitesare ones that live insideof the hosts body and are adapted to attach and obtain nourshment and habitat space. They can feed on digested nutrients or sap or can become encysted in muscles, organs or fleshy tissue. Endoparasites weaken the host by stealing nutrients and/or interfering with normal organ/tissue function.
Parasitism Hosts have evolved adaptations to lessen the impact of parasites. Defenses include secretions such as tears, mucous or resin (plants) to prevent parasites from entering the body. Parasites can be removed during ritual grooming among social animals or through the ingestion of chemicals that will kill the parasite.
Mutualism In a mutualistic relationship both species benefit from the interaction. The association occurs in such a way that each species is dependent upon the other to obtain resources that it cannot obtain by itself. Humans often interfere in these relationships by altering the population of one species so that the other species then suffers.
Commensalism In a commensalistic relationship one species benefits while the other one remains unaffected. This type of relationship can provide food, transportation and/or habitat for the benefitting species. This type of relationship sometimes involves a vast size difference in the species in the interaction.
Ammensalism In an ammensalistic relationship one species is harmed while the other one remains unaffected. This is a rare type of interaction that is often accidental in nature on the part of the unaffected species. Effects include destruction of habitat or sickness from consuming improper food sources.
