Ecosystems: What they are Chapter 2

Abiotic: All non-living parts of the environment. Biotic vs. Abiotic Biotic: anything living, once living, potential for life parts of the environment. Abiotic: All non-living parts of the environment.

OPCEB Old People Can’t Eat Beans Organism Population Community Ecosystem Biosphere Biotic components only Abioitc and Biotic components All life exists in 13 miles (5-6 above sea level)

Definitions Population- One species living in same place at same time Community (association)- variety of species living in same place at same time. Ecosystem- all living and non-living. Ecotone- transitional region between two ecosystems. Landscape- group of interacting ecosystems. Biome- similar ecosystems or landscapes grouped together.

Biotic Structure (trophic levels) Biomass pyramid Secondary consumers Primary consumer Biomass- total combined weight of all the organisms at each trophic level. Typically decreases by 90% at each higher level. Terrestrial typically 3-4 trophic levels, aquatic is typically 4-5 trophic levels before the system “runs out of energy”.

Trophic Categories Autotrophs (producers)- self feeders. Either photosynthetic or chemosynthetic. Heterotrophs (consumers, detritus feeders, decomposers)- Herbivores Carnivores Omnivores Detritiovores Decomposers

Organic vs. Inorganic Organic- All those materials that make up the bodies of living organisms (more in Chapter 3) Inorganic- materials and chemicals in air, water, rocks, and minerals, which exist apart from the activity of living organisms.

Types of Consumers Predator eats prey. Predation thus ranges from interactions between carnivores and herbivores, to herbivores feeding on plants, to parasites feeding on hosts.

Definitions Mutualism Symbiosis Mutual feeding relationship to both species (bee and flower) Symbiosis Two species living in close relation to each other. Some are actually not able to survive apart (lichen-fungus and alga), some may include parasitic relationships (mosquito/human), some may be mutualistic.

Habitat vs. Niche Habitat- the kind of place where a species is biologically adapted to live (defined by the plant life and physical environment) Niche- refers to what the animal feeds on, where it feeds, when it feeds, where it finds shelter, how it responds to abiotic factors, and where it nests.

Competitive Exclusion Principle When two species directly compete, one generally perishes. Happens often with the introduction of an exotic species. Example: introduction of the European rabbit to Australia: lead to the destruction of many marsupial varieties.

Abiotic conditions and resources Conditions: Vary in space and time but are not used up or made unavailable to other species. Temperature, wind, pH, salinity, fire Resources: biotic or abiotic factors that are consumed by organisms. Water, chemical nutrients, oxygen, sun light.

Limiting factor: A factor that limits growth. Population Density: Decreases if any factor falls out of the optimum zone.

Law of Limiting Factors Any one factor being outside the optimal range will cause stress and limit growth, reproduction, or even survival of a population. AKA Liebig’s law of minimums Ultimate limiting factor= the organism’s genetic potential. A mouse will never grow to be a giant Leads to different biomes because different plants/animals can tolerate different circumstance.

Synergistic Effect AKA= Synergism Two or more factors come together interacting in a way that causes an effect much greater than one would anticipate from the effects of each of the two acting separately.

Climate Average temperature and precipitation (weather) that may be expected on each day throughout the entire year. Precipitation and temperature can vary with respect to distance from equator (latitude) and elevation from earth. It can also vary based upon topography (mountains and valleys) and soil type.

6 major biomes Temperate deciduous forest Grassland/prairie Desert Tropical rain forest Coniferous forest Tundra See table 2-3 for general characteristics and figure 2-18 for distribution.

Cold Wet Hot Dry

Microclimates Conditions found in a specific localized area. South facing slope will receive more direct sunlight in the northern hemisphere and will therefore be drier than the north facing slope.

Factors that affect biotic parts of an ecosystem: Competition Predation Distribution of plants Lack of food Lack of habitat Abiotic Temperature Precipitation Soil type Topography Salinity Acidity Physical barriers

History of man: Hunter/gatherer period: no settlement, roamed land for food. Neolithic revolution: settled in to one place, animal husbandry, crops, trade, reduced mortality. Industrial revolution: global commerce, use of fossil fuels, factories, large cities, pollution, population growth, human system. Environmental revolution: new trend toward a sustainable future.