Bot-Lec (Sem-1) - Chapter 17: Plant Ecology

ecology

the study of relationships among living things and their environment; provides an insight into the various systems within ecosystems as they are and how they may change in the future;

components of the ecosystem; ecosystem dynamics; tolerance and limiting factors

structure of ecosystems

habitat

area or place where an organism or group of organisms lives or where one will go to find the organism

light; air; water; soil

requirements for a plant habitat

shelter; water; food; space

main components of a habitat

shelter

a main component of a habitat; protects an organism from predators and weather; e.g. a tree provides sheltered habitats for various organisms

water

a main component of a habitat; some plants like cattails grow best in marshes and swamps

food

a main component of a habitat; plants being producers in an ecosystem serve as food for many organisms

space

a main component of a habitat; varies from species to species. E.g. Coast redwood trees can reach more than 4.5 meters in diameter

ecosystem

composed of a community of organisms interacting with one another and with their physical environment

biotic (living)

community of organisms

abiotic (nonliving)

the physical environment

nutrient cycles and energy flows

keep these components connected in the ecosystem

biotic components; abiotic components

components of the ecosystem

producers; consumers; decomposers; detritivores; saprotrophs

five biotic components

producers

biotic component; organisms like plants and algae that produce their own food through photosynthesis or chemical processes

photoautotrophs; chemoautotrophs

two types of producers

herbivores; carnivores; omnivores

three types of consumers

decomposers

biotic component; break down dead organisms and recycle nutrients

detritivores

biotic components; consume decomposing organic matter

saptotrophs

biotic component; absorb nutrients from decayed material

abiotic components

water; air (atmospheric gases); soil (edaphic); light; wind; temperature; physiographic (nature of land surface); pH; salinity; relative humidity

niche

ecosystem dynamic; defined as the set of conditions in which a particular species can thrive, outcompeting other organisms

ecological niche; spatial niche; trophic niche; fundamental niche; realized niche

ecosystem dynamics (niches)

ecological niche

ecosystem dynamics; structural and instinctive limitations of the species which govern its distribution in the given habitat

spatial niche

ecosystem dynamics; mostly in terms of the microhabitat; physical space inhabited by the plant; two species cannot fill the same niche

trophic niche

ecosystem dynamics; emphasis on energy relations brought upon by differences in trophic positions; characterized by the plant’s role in the ecosystem; determines how plants compete for light, water, and nutrients

fundamental niche

ecosystem dynamics; maximum hypervolume that can be occupied by an organism in the absence of competition pressure from other organisms

realized niche

ecosystem dynamics; smaller hypervolume within a larger hypervolume which the organism was successfully occupied as constraints from competition were imposed to it by other organisms

Hutchinson’s Niche

ecological niche model by the zoologist G. Evelyn Hutchinson wherein the environmental conditions and resources which help a population or species persist form an “n-dimensional hypervolume”

competitive exclusion principle

states that two species using identical resources and/or environments cannot coexist

fitness; tolerance range; euryhaline species; stenohaline species; limiting factors

tolerance and limiting factors

fitness

tolerance and limiting factors; ability to reproduce and contribute more individuals to the next generation

tolerance range

tolerance and limiting factors; level of physicochemical factors on which the organisms are said to function and survive normally

euryhaline species

tolerance and limiting factors; an organism, such as Rhizopora spp., with wide tolerance range for salinity

stenohaline species

tolerance and limiting factors; organisms with narrow tolerance range for salinity, such as jellyfish

limiting factors

tolerance and limiting factors; negatively affect the growth, reproduction, and survival of the species;

population

individuals of the same species

community

an interacting group of various species in a common location

community ecology

studies how populations of different species interact and function with in a specific area or habitat

intraspecific interaction

refers to the interactions between two individuals of the same species; for example, same species competing for resources, cooperation, territoriality, social structures, and reproductive strategies

interspecific interaction

are interactions between two species

predation; competition; symbiosis

three major types of community interactions

predation

community interaction; members of one population will benefit in the interaction while members of another population were harmed

competition

community interaction; usually take place between two organisms that strive for the same limited resources

symbiosis

community interaction; at least one species benefits while the other species may be benefitted, harmed, or neither benefitted nor harmed

mutualism; parasitism; commensalism

types of symbiotic relationships

mutualism

symbiotic relationships; both interacting organisms benefit in the relationship

parasitism

symbiotic relationships; one species benefits in the relationship while the others is harmed

commensalism

symbiotic relationships; the interaction benefits one species, the commensal, while the other species, the host, is neither benefitted nor harmed

biotic potential

capability for growth of a given population under hypothetical optimum conditions, in an environment without limiting factors for such growth

environmental resistance

refers to the limiting factors and their effects that prevent a population from growing indefinitely

carrying capacity

maximum number of individuals in a population that an ecosystem can indefinitely support

terrestrial ecosystem

tundra; taiga; temperate deciduous forest; tropical rain forest; grassland; desert

six distinct types of biomes

tundra

a type of biome; mostly found in the northern hemisphere around the north pole, where the climate is cold and windy and rainfall is scant; characterized for being a treeless plain (from Finnish word tunturi), which the name of the ecosystem literally means, and by the permafrost, which is a permanently frozen layer of ground

taiga (boreal/coniferous forest)

a type of biome; vegetation is primarily dominated by conifers, such as pine trees (Pinus sp.), spruce (Picea sp.), and firs (Abies sp.); name is a Russian word which means “land of the little sticks”; located in the northern hemisphere just below the tundra; characterized by long winters and moderate to high annual precipitation;

temperate deciduous forest

a type of biome; named according to its amenable climate (temperate) and even distribution of rainfall throughout the year; characterized by deciduous trees that shed their leaves as cold weather approaches; constantly exposed to four seasons, namely winter, spring, summer, and autumn (fall); found between the polar regions and the tropics

tropical rain forest

a type of biome; found in the equatorial region between the Tropic of Cancer (23.5o N) and Tropic of Capricorn (23.5o S) where the climate is hot and moist; characterized with evergreen forests with moderately stable temperature and high average annual precipitation; most biodiverse ecosystem and also the most threatened; world’s largest tropical rainforest is the Amazon rainforest which covers much of northwestern Brazil and extending into Colombia, Peru and other South American countries

grassland

a type of biome; primarily dominated by grasses and grass-like species with very few trees and shrubs; low annual precipitation, hence too dry for trees to grow, but with enough soil water to support the grasses; called prairies in North America, Asian steppes, savannahs and veldts in Africa, Australian rangelands, and pampas, llanos and cerrados in South America

desert

a type of biome; the driest among the terrestrial ecosystems; has the lowest annual precipitation hence it is devoid of vegetation and only plants that can store water such as cactuses are able to thrive in this ecosystem; found around the Tropic of Cancer and Tropic of Capricorn, where the sun hits the earth surface at almost 90o angle overhead particularly at equinoxes; e.g. Gobi desert and Taklamakan desert in Asia, the Sahara desert in northern Africa, and the Great Sandy desert and Simpson desert in Australia