B4.2 Ecological niches

biotic and abiotic elements of ecological niches

• zones of tolerance for abiotic variables determine habitat of species

• food obtained from light and water and carbon dioxide or other organisms; specialization to minimize competition, adaptation to effectively compete

• utilization of services of other species (ex. pollination, support from plant structures)

adaptations of predators

• physical - vampire bats* have large and sharp/pointed incisors and canines to pierce prey

• chemical - black mambas produce venom containing neurotoxins to paralyze prey and swallow them without resistance

• behavioral - grizzly bears learn ambush strategies to catch migrating salmon

adaptations of prey

• physical - buff-tip moths camouflage to resemble broken birch twigs

• chemical - cinnabar moth caterpillars - black and yellow warning stripes against predators, toxins retained from feeding on ragwort

• behavioral - blue-striped snappers practice schooling behavior, reducing chances of predation

types of adaptations

• behavioral adaptations - change relatively quickly

• structural adaptations - requires genetic change

• chemical adaptations - new enzymes/ways of regulation may take millions of years

adaptations of plant form for harvesting light

• dominant leading shoot - rapid growth to forest canopy, unshaded by other trees

• lianas - climb and use other trees for support, require less xylem tissue (wood) production

• epiphytes - grow on trunks and branches of trees, higher light intensity but minimal soil

• strangler epiphytes - climb up and outgrow and kill other trees

• shade-tolerant shrubs and herbs - absorb light reaching the forest floor

fundamental niche

full range of environmental and social conditions under which it could potentially survive and reproduce, taking into account all tolerance levels to abiotic and biotic factors

realized niche

specific set of conditions under which the species actually does survive in a given habitat or ecosystem, with limitations of other species being present; conditions to which it is actually adapted

competitive exclusion and the uniqueness of ecological niches

every species must have a realized niche that differs from the realized niches of all other species to survive in an ecosystem