APES Module 1 | The Living World

Ecosystem

Ecosystem

a biological community of interacting organisms and their physical environment.

Symbiosis

interaction between two different organisms living in close physical association, typically to the advantage of both.

Mutualism

interactions between two species where both benefit.

Commensalism

an association between two organisms in which one benefits and the other derives neither benefit nor harm.

Parasitism

the practice of living as a parasite in or on another organism.

Interspecific competition

the competition between species for shared resources such as space, food and nesting sites during the breeding season and also for roosting sites during the non-breeding season

Intraspecific competition

a competition between individuals from the same species (cospecifics)

Resource partitioning

when different organisms within one ecosystem split up an area so that they will not compete for the same resources and when those organisms have a special adaptation

Ecological Niche

a term for the position of a species within an ecosystem

Competitive exclusion

the inevitable elimination from a habitat of one of two different species with identical needs for resources.

Limiting Factor

a variable of a system that causes a noticeable change in output or another measure of a type of system.

Biome

a grouping of terrestrial ecosystems on a given continent that is similar in vegetation structure, physiognomy, features of the environment and characteristics of their animal communities.

Taiga/Boreal Forest

Climate: long, cold winters. Short, mild summers. Moderate precipitation and high humidity.

Key Features: Nutrient-poor and acidic soils because of falling needles. Only in the Northern Hemisphere and moderate productivity.

Dominant plants: needle-leaf coniferous trees such as spruce and fir; some broadleaf deciduous trees; small, berry-bearing shrubs.

Animals: Canadian lynx, Gray wolf, River otter, Wolverine, Grizzly bear

Human Impact: Affected by mining, oil extraction, logging, and hydroelectric development.

Temperate Rainforest

Climate: mild temperatures"; abundant precipitation during fall, winter, and spring with relatively cool, dry summer.

Key Features: rocky, acidic soils; coastal biome; oceans moderate temperature and provide water vapor for precipitation.

Dominant Plants: Douglas fir, Sitka spruce, western hemlock, redwood; ground layer of mosses and ferns.

Animals: Cougar, Elk, Porcupines, Tree frog, Muskrat

Human Impact: logging, mills, and coastal fisheries; recreation and tourism

Temperate Seasonal Forest

Climate: cold to moderate winters; warm summers; year-round precipitation

Key Features: fertile soils, rich in organic material from seasonal decomposition of leaves; long growing season; moderately high productivity

Dominant plants: broadleaf deciduous trees; some conifers; flowering shrubs; herbs

Animals: Bald eagle, Coyote, Black bear, White-tailed deer

Human Impact: Much land is used for agriculture, development, and industry

Tropical Rainforest

Climate: hot and wet year-round

Key Features: thin, nutrient-poor soils; rapid decomposition and quick uptake of nutrients; “seasons” depend on location of ITCZ; most productive land biome

Dominant Plants: broad-leaved evergreen trees; ferns; large woody vines and climbing plants; orchids and bromeliads

Animals: Sloth, Cobra, Chimpanzee, Toucan, Beetles

Human Impact: Deforestation causes loss of habitat, loss of biodiversity, soil erosion, climate change, destruction of Indigenous cultures, and loss of potential medicines.

Shrubland/Woodland

Climate: hot, dry summers; cool, moist winters

Key Features: thin, nutrient-poor soils because of leaching by winter rains; periodic wildfires

Dominant Plants: woody evergreen shrubs with small, leathery leaves; fragrant, oily herbs that grow during the winter and die in summer

Animals: Bobcat, Jackal, Javelina, Cactus wren, Roadrunner

Human Impact: Human ignited wildfires; vineyards

Temperate Grassland

Climate: warm to hot summers; cold winters; moderate, seasonal precipitation

Key Features: fertile soils; dry, windy conditions cause fires that prevent tree growth; productive

Dominant plants: lush, perennial grasses and herbs; most are resistant to drought, fire, and cold

Animals: Prairie dog, Badger, Prairie vole, Fox squirrel, Mink

Human Impact: Agriculture, grazing, urbanization, habitat fragmentation, hunting and poaching

Savanna(Tropical Seasonal Forest)

Climate: warm temperatures; seasonal rainfall

Key Features: fertile soil compacted by grazing animals; seasons due to moving ITCZ; large herds of migrating animals follow seasonal precipitation

Dominant Plants: Tall, perennial grasses; some drought-tolerant and fire resistant trees or shrubs.

Animals: African elephant, Black mamba, Baboon, Emu, Mongoose

Human Impact: Conversion to land for agriculture and grazing; hunting, poaching, mining, recreation, and tourism

Desert

Climate: low precipitation; variable temperatures

Key Features: soils rich in minerals but poor in organic material; low resistance and resilience; low diversity; very low productivity

Dominant Plants: cacti and other succulents; creosote bush and other plants with short growth cycles

Animals: Armadillo, Jackrabbit, Gila monster, Kangaroo rat, Fennec fox

Human Impact: Use of ATV's, military exercises, drilling for oil, mining, nuclear waste disposal

Tundra

Climate: short and soggy summers. Long, cold, and dark winters. Low precipitation.

Key Features: Poorly developed soils. Permafrost. Found at high latitudes. Short growing season, low productivity.

Dominant plants: Ground-hugging plants such as mosses, lichens, sedges, and short grasses.

Animals: Caribou, Artic fox, Snowy owl, Musk ox, Ermine

Human Impact: Fragile biome affected by climate change and oil and gas pipelines

Freshwater Biomes

include Streams, Rivers, Ponds, and Lakes. Vital resource for drinking water.

Marine Biomes

include Oceans, Coral Reefs, Marshlands, and Estuaries. Algae in marine biomes supply a large portion of the Earth's oxygen, and also take in carbon dioxide from the atmosphere.

Nitrogen Cycle

1. N2(Nitrogen Gas)

2. Nitrogen Fixation due to bacteria(N2—>NH3)

3. Ammonification due to bacteria(NH3—>NH4)

4. Nitrification(NH4—>NO2+NO3)(Fertilizer)

5. Assimilation

6. Denitrification due to bacteria (NH3,NH4,NO2,NO3—>N2)

7. Decomposers can be after Nitrification or Assimilation and revert to Nitrogen Fixation or Ammonification

Carbon Cycle

1. Photosynthesis: Plants absorb carbon dioxide

2. Cellular Respiration: autotrophs and heterotrophs break down molecules through respiration and release carbon into the atmosphere

3. Decomposition: When the animals die, they decompose, and their remains become sediment, trapping the stored carbon in layers that eventually turn into rock or minerals.

4. Carbon Sinks: The ocean, the atmosphere, and living organisms act as storage for carbon.

5. Phytoplankton: responsible for most of the transfer of carbon dioxide from the atmosphere to the ocean

6. Cyanobacteria: breaks down organic compounds. Similar to phytoplankton

Phosphorus Cycle

1. Weathering: Over a long period, phosphates found in the sedimentary rocks as PO₄^3-_, are leached out of the disintegrated rocks from its various environmental sources in the form of inorganic phosphate ions.

2. Mineralization by plants: Plants absorb organic phosphorus present in soil and underground water and convert them to inorganic forms for utilization is called mineralization.

3. Assimilation by animals: Herbivorous and predatory animals, absorb phosphorus when they consume these plants for their food

4. Decomposition by microorganisms: Microorganisms such as bacteria and fungi decompose organic phosphates back into the inorganic form, which is then returned to the soil and water bodies. Phosphorus-containing compounds may also be carried in the surface runoff to rivers, lakes, and oceans to form sediments.

5. Geological uplift by tectonic movements: Over long periods, sedimentary rocks containing phosphorus may be moved from the ocean to the land by a process called geological uplift. The phosphorus thus deposited as sediments is ultimately released back into the environment through the process of weathering, thus completing the cycle.

Hydrologic Cycle

1. Condensation: the process whereby water vapor is changed into a liquid state

2. Precipitation: Liquid water evaporates into water vapor, condenses to form clouds, and precipitates back to earth in the form of rain and snow.

3. Runoff: occurs when there is excessive precipitation and the ground is saturated

4. Infiltration: Water infiltrates the soil by moving through the surface.

5. Percolation: the movement of water through the soil itself.

6. Evaporation: Liquid water evaporates into water vapor

7. Transpiration: the evaporation of water from plants through stomata.

8. Deposition: occurs when water vapor (gas) changes into ice (solid) without going through the liquid phase

9. Sublimation: the conversion between the solid and the gaseous phases of matter, with no intermediate liquid stage

Primary Productivity

the rate at which energy is converted to organic substances by photosynthetic producers

1. GPP: The total amount of carbon compounds produced by photosynthesis of plants in an ecosystem in a given period.

2. NPP: the amount of biomass or carbon produced by primary producers per unit area and time, obtained by subtracting plant respiratory costs (Rp) from gross primary productivity (GPP) or total photosynthesis.

Trophic Levels

Primary producers use energy from the sun to produce their own food in the form of glucose, and then primary producers are eaten by primary consumers who are in turn eaten by secondary consumers, and so on, so that energy flows from one trophic level.

Energy Flow and 10% Rule

Energy is lost as metabolic heat when the organisms from one trophic level are consumed by organisms from the next level. Each level only gains 10% of the energy from the previous level of the energy pyramid.

1. The 1st Law of Thermodynamics says that energy cannot be created or destroyed.

2. The 2nd Law of Thermodynamics says that as energy is transferred more and more of it is lost through heat.

Food Web

1. Food Chain: a linear sequence of organisms through which nutrients and energy pass as one organism eats another

2. Food Web: consists of all the food chains in an ecosystem

3. Positive and Negative Feedback: in the food web that will either cause the ecosystem to change(positive) or help it resist change(negative)