Unit 1: Ecosystems

Ecosystem

A system of interconnected elements: a community of living organisms and its environment

Biotic

Living component

Abiotic

Non-living component

Evolution

A change in a population’s genetic composition over time

Phylogenetic Tree

A figure used to model evolution

Speciation

The creation of new species

Species

A group of organisms that capable of breeding with one another and incapable of breeding with other species

Evolutionary Fitness

Organisms that are better adapted for their environment and are able to survive and reproduce

Natural Selection

Beneficial characteristics are passed down while unfavourable characteristics are either lost or less common in the following generation

Selective Pressure

Any cause that reduces reproductive success in a portion of the population

Gene Pool

Total genetic makeup of the population

Genetic Drift

The accumulation of changes in the frequency of alleles over time due to sampling errors

Sampling Errors

Changes that occur as a result of random chance (mutations)

Microevolution

Small-scale changes over a relatively short period of time

Macroevolution

Large-scale patterns of evolution within biological organisms over a long period of time

Extinction

When a species cannot adapt quickly enough to environmental change and all members of the species die

Biological Extinction

True extermination of species; no individuals of the species exist

Ecological Extinction

Too few individuals of a species to perform its ecological function

Commercial/Economic Extinction

A few individuals exist but the effort needed to locate/harvest them is not worth the expense

Predation

When one species feeds on another and it drives changes in population size

Symbiotic Relationships

Close, prolonged associations between two or more different species that may benefit each member

Mutualism

Both species benefit from the relationship

Commensalism

One species benefits from the relationship while the other species is unaffected

Parasitism

One species is benefitted from the relationship while the other species is harmed

Biomes

Ecosystems that are based on land

Aquatic Life Zones

Ecosystems that are based in the water

Ecotones

Transitional area where two ecosystems meet

Ecozones/Ecoregions

Smaller regions with ecosystems that share similar physical characteristics

Deciduous Forest

Rainfall: 75-250 cm

Soil type: Rich with high organic content

Ex: N.A., Europe, Australia, East Asia

Tropical Rainforest

Rainfall: 200-400 cm

Soil type: Poor

Ex: S.A., West Africa, S.E. Asia

Grasslands

Rainfall: 10-60 cm

Soil type: Rich

Ex: Plains, prairies, savannas, steppes, velds, pampas

Coniferous Forest

Rainfall: 20-60 cm (Maj. summer)

Soil type: Acidic

Ex: Northern N.A., northern Eurasia

Tundra

Rainfall: < 25 cm

Soil type: Permafrost

Ex: Northern latitudes of N.A., Europe, and Russia

Chaparral

Rainfall: 50-75 cm (Maj. winter)

Soil type: Shallow and fertile

Ex: Western N.A., Mediterranean

Deserts

Rainfall: < 25 cm

Soil type: Coarse

Ex: 30 degrees north and south of the Equator

Temperate Rainforest

Rainfall: > 140 cm

Soil type: Richer than tropical rainforests

Ex: Americas, South Africa, Europe, Russia, N.E. Asia, Australia, New Zealand

Savanna

Rainfall: 10-30 cm

Soil type: Porous, thin layer of humus

Ex: Australia, S. America, India, half of Africa

Epilimnion

Uppermost and most oxygenated layer in freshwater

Hypolimnion

Lower, colder, and denser layer of freshwater

Thermocline

Demarcation line between the epilimnion and hypolimnion

Littoral Zone

Abundant sunlight; shallow freshwater near the shoreline

Limnetic Zone

Surface of open freshwater; organisms depend on sunlight

Profundal Zone

Aphotic and low oxygenated zone of freshwater

Benthic Zone

Sediment surface and sub-surface layer of freshwater bodies

Estuary

Where the sea and a river meet

Wetlands

Areas along the shores of fresh bodies of water; fed only by rainwater and ephemeral water bodies

Mangrove Swamps

Coastal wetlands found in tropical and subtropical regions

Barrier Islands

Landforms that lie off coastal shores

Coral Reef

Type of barrier island formed by a community of living things: mainly cnnidarians

Coral Bleaching

Increase in ocean temperatures and dissolved CO2 > Increased acidic waters > Expelled colourful algae of coral

Coastal Zone

Area of ocean water closest to land / end of the continental shelf

Euphotic Zone

Photic upper layers of ocean water, most oxygenated zone

Pop. density level: High

Bathyal Zone

Middle region of ocean water; receives little light and is comprised of cold water

Pop. density level: Medium

Abyssal Zone

Deepest region of ocean water; high pressures and low oxygen

Pop. density level: Low

Upwellings

Seasonal movement of water from the cold and nutrient-rich bottom to the surface of the water

Red Tide

Proliferation of dinoflagellates (toxic algal bloom)

Temperature that water is densest at:

3.98 degrees Celsius / 39 degrees Fahrenheit

Reservoir

A place where a large quantity of a nutrient sits for a long period of time (ex. ocean)

Exchange Pool

A place where a nutrient sits for a short period of time (ex. cloud)

Residency Time

The amount of time a nutrient spends in a reservoir or an exchange pool

Law of Conservation of Matter

Matter cannot be created nor destroyed

Percolation

The filtering of a liquid or gas through a porous surface or substance

Transpiration

Large amounts of water into the air through plants

Respiration

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O

Photosynthesis

6CO₂ + 6H₂O + sunlight → C₆H₁₂O₆ + 6O₂

Intake of CO2 to produce carbohydrates

Combustion

Hydrocarbons (C_xH_y) + O₂ → CO₂ + H₂O

Release of carbon back into the atmosphere through fossil fuels

Nitrogen Fixation

The “fixing” of atmospheric nitrogen for biological availability

Atmospheric nitrogen > NH3 or NO3-

Nitrification

The conversion of ammonia (NH3) or ammonium (NH4+) into nitrite (NO3) then nitrate (NO3-)

Assimilation

Absorption of ammonia, ammonium, and nitrate ions by plants to heterotrophs

Ammonification

Conversion of dead organisms to NH3 or NH4+

Denitrification

NH3 > Nitrites and Nitrates > N2 and N2O

Phosphorus Cycle

Cycle of phosphorus everywhere except the atmosphere

Eutrophication

When a body of water receives excess nutrients causing the overgrowth of algae and the depletion of oxygen

Autotrophs / Producers

Organisms that produce their own organic compounds from inorganic chemicals

Heterotrophs

Organisms that obtain energy by consuming other organisms

Anaerobic

Without oxygen

Chemotrophs

Chemosynthesis

CO2 + 4H2 S + O2 > CH2 O + 4S + 3H2 O

Net Primary Productivity (NPP)

Amount of energy that plants pass on to the community

Gross Primary Productivity - Respiration

Gross Primary Productivity

Amount of energy that plants produce in photosynthesis

Detritivores

Organisms that derive energy from coming nonliving organic matter

Decomposers

Organisms that consume dead plant and animal material, returning nutrients to the environment

Saprotrophs

Decomposers that use enzymes to break down dead organisms and absorb nutrients

Trophic Level

Feeding level

10% rule

90% of energy is put out as heat while 10% of the energy can be passed onto the next trophic level

Energy Pyramid

Amount of energy available at each trophic level organized from greatest to least