Ecology Ecology- Greek words oikos, meaning “house” and logos, meaning “study of”.
BIOSPHERE- broadest level of organization, thin volume of Earth and its atmosphere that supports life; all organisms found within this biosphere. • The biosphere is composed of smaller units called ECOSYSTEMS- all of the organisms and the nonliving environment found in an area.
A COMMUNITY-all living organisms living in an area. Ecologists studying a community often focus on how species interact. • POPULATION (below community) includes all the members of a species that live in one place at one time.
Organisms are able to survive within a wide range of environmental conditions. TOLERANCE CURVE- graph of performance versus values of an environmental variable, such as temperature • Some organisms can adjust their tolerance to abiotic factors through the process of ACCLIMATION. How do animals’ red blood cell count change as their elevation increases?
CONFORMERS- do not regulate their internal conditions. • REGULATORS- use energy to control some of their internal conditions. • NICHE- species’ way of life, role that the species plays in its environment.
FUNDAMENTAL NICHE- range of conditions that a species can potentially tolerate and the range of resources it can potentially use.
REALIZED NICHE- range of resources an organism actually uses. Which of these is the broadest? Most narrow?
What’s the difference between a specialized and generalized species?
Predation is a powerful force in a community. What is a predator? Prey? • Predator’s survival depends on being able to capture prey; prey’s survival depends on escaping the predator. • PARASITISM -one individual is harmed while the other individual benefits. One individual is the parasite while the other is the host.
ECTOPARASITES-external parasites; do not enter their host’s body. • ENDOPARASITES- internal parasites that live inside the host’s body.
A tick feeding on a human is an example of a.parasitism. b. mutatalism. c. competition. d. predation.
MUTUALISM- both species derive some benefit (ie: pollination). • COMMENSALISM-one species benefits and the other is not affected.
SUCCESSION- sequential replacement of populations in an ecosystem. • PRIMARY SUCCESSION-development in an area that has not supported life previously (bare rock, a sand dune, a volcanic island) • SECONDARY SUCCESSION- replacement of species that follows disruption of an existing community.
PIONER SPECIES- species that predominate early in succession; tend to be small, fast-growing, and fast-reproducing. • A community proceeds through a predictable series of stages until it reaches a stable end point, called the CLIMAX COMMUNITY.
AUTOTROPHS- produce their own food. HETEROTROPHS- cannot make their own food. • Autotrophs- can be a PRODUCER or carry out CHEMOSYNTHESIS. • GROSS PRIMARY PRODUCTIVITY- rate at which producers in an ecosystem capture energy use that energy to make sugar, used for cellular respiration or to make new organic material.
BIOMASS- organic material in an ecosystem; Producers add biomass to an ecosystem by making organic molecules. • Unlike autotrophs, heterotrophs cannot make their own food. Heterotrophs are CONSUMERS: HERBIVORES, CARNIVORES, or OMNIVORES. What are they?
DETRITIVORES- consumers that feed on the “garbage” of an ecosystem. What bird is an example of a detritivore? • Which is an herbivore, carnivore, omnivore or detritivore?
Bacteria and fungi belong to a class of detritivores called DECOMPOSERS: cause decay by breaking down the complex molecules in dead tissues. • Whenever one organism eats another, energy is transferred. As a result, energy flows through an ecosystem; producers consumers.
TROPHIC LEVEL- organism’s position in the sequence of energy transfers. What level do all producers belong (1st, 2nd, 3rd…?) • FOOD CHAIN- single pathway of feeding relationships among organisms that results in energy transfer.
The diagram below shows a food web. Which population would probably increase if the tadpole population decreased? a. herons b. alligators c. fish d. algae
Which of the following most likely occupies the location marked X in this food web? • decomposers b. primary consumers c. producers d. secondary consumers
10% Rule: roughly 10% of the total energy consumed in one trophic level is incorporated into the organisms in the next level. • In Michigan, ecologists found that only 1.3% of the total energy (grass) consumed by the moose was transferred to the wolves through the wolves’ predation on the moose.
The diagram below shows an energy pyramid. Approximately how much energy is available to the secondary consumers in this energy pyramid? a. 10 kcal/m2/year b. 100 kcal/m2/year c. 1,000 kcal/m2/year d. 5,000 kcal/m2/year
BIOGEOCHEMICAL CYCLE- matter moves from the abiotic portion of the environment, (atmosphere), into living things, and back again. • The atmosphere contains water in the form of water vapor. In addition there is GROUNDWATER. WATER CYCLE: movement of water between these reservoirs.
90% of the water that evaporates from terrestrial ecosystems passes through plants in a process called TRANSPIRATION. • Look at (sketch if you need to) Figure 18-12 on pg. 371 in your notes. Know these terms: transpiration, precipitation, runoff, evaporation, percolation.
Acid rain can eat through stone and metal. It has accelerated the natural weathering process of this scarred stone angel's face. Damage from acid rain mars some of the world’s finest cultural monuments. Emissions reductions, however, have helped slow the rate of damage in North America and Europe. India’s TajMahal has not fared as well. The mausoleum built by the Mughal Emperor Shah Jahan for his beloved wife MumtazMahal is losing its white luster and turning a sickly pale shade. Scientists blame pollution from local foundries and a nearby oil refinery.
Photosynthesis and cellular respiration form the basis of the CARBON CYCLE. Autotrophs use CO2 (along with water and solar energy) to make carbohydrates. Heterotrophs use oxygen to break down carbohydrates during cellular respiration. Byproducts of cellular respiration: CO2 and water. Decomposers release CO2 into the atmosphere when they break down compounds. • How have humans upset the carbon cycle? • Look at (sketch if you need to) Fig. 18-13 on pg. 372.
At position Y, carbon is most likely to be in which of the following forms? a. protein b. carbon solid c. carbohydrate d. carbon dioxide
Organisms need nitrogen to make proteins and nucleic acids. NITROGEN CYCLE- pathway that nitrogen follows within an ecosystem. • Most plants can only use nitrogen in the form of nitrate. The process of converting nitrogen gas to nitrate is called NITROGEN FIXATION. NITROGEN-FIXING BACTERIA convert nitrogen gas into ammonia, then nitrate.