APES Unit 1: The Living World - Ecosystems

Ecosystems

• all ecosystems on Earth are interconnected in the biosphere

* levels of organization w/in ecosystems (OPCEB)

• Organism/Individual

• Populations

• Community

• Ecosystem

• Biosphere/Earth

Competition

caused by individuals competing for a shared limited resource

Competitive Exclusion Principle

2 species competing for the same resource cannot coexist

• 1 species will perform better & drive the other into extinction

Resource Partitioning

2 species evolve to divide a resource through behavior/morphology to avoid compt

Resource Partitioning

Temporal - using resource @ diff times

Spatial - using diff areas of a shared habitat

Morphological - evolution of differences in body size/shape

Predation

1 animal kills & consumes another animal, to consume their energy

relationship: +/-

Parasitoid

1 organism consumes its prey by laying its eggs inside another organism (host)

• hatch & slowly consume host

• relationship: +/-

Parasitism

an organism lives on another organism consuming a small fraction of the host to keep it alive

• relationship: +/-

Herbivory

consumption of plants by animals

• an increase in herbivores can lead to collapse of ecosystem, so predation can sometimes keep them under control

• relationship: +/-

Mutualism

both species benefit

• relationship: +/+

Commensalism

1 species benefits & another is unaffected

• relationship: +/0

Native Species

species evolve to their ecosystems OT

Exotic/alien species

out of their historical range & can have an impact on the native species

Invasive Species

species that spread quickly & cause harm to native ecosystems r considered

Mod 2: Terrestrial Biomes

Biome

region of the world where particular plants & animals can be found

Terrestrial Biomes

Categorized by:

• dominant plant growth forms

• annual temp & precipitation (climate)
  characteristic organisms

* Temp

* Precipitation

* Plants

* Organism Characteristics

Aquatic Biomes

Categorized by:

• salinity

• depth

• water flow

• temp

• nutrient availability

• turbidity (measure of cloudiness)

Habitat

where a particular species lives in nature, not characterized by plants

Climate Diagram

shows the months of the yr & patterns of temp & precipitation on 1 graph

Tundra

treeless biome w/low-growing vegetation like woody shrubs mosses, heaths & lichens

• short growing season limited by temp

• defined by permafrost, a frozen layer of soil that prevents drainage

• low soil nutrients

Taiga/boreal forest

made of primarily coniferous evergreen trees

• cold temps & relatively low precipitation

• short growing seasons

• soils r poor in nutrients due to slow decomposition

Temperate Rainforest

• mod temps & high precipitation

• coniferous trees & redwoods

• nutrient-rich soil (Lots of dead organic matter - leaves & warm temp/moisture for decomp

Temperate Seasonal Forest/Temperate Deciduous Forest

warm summers & cold winters

• dominated by broadleaf deciduous trees like beech maple & hickory

• conifers present

• plant growth limited by temp

• high soil fertility

Shrubland/Woodland

hot, dry summers & mild rainy winters

• drought resistant shrubs like yucca, scrub oak, & sagebrush

• plant growth limited by high temps

• soil is low in nutrients

Temperate Grassland/Cold Desert

cold, harsh winters & hot dry summers

• grasses & non woody flowering plants

• plant growth limited by precipitation in summer & temp in winter

• very rich soil

Tropical Rainforests

warm & wet biome

• most biodiversity of any terrestrial biome containing 2/3 of Earth’s terrestrial species

• nutrient-poor soil (high temp & rainfall lead to rapid decomp of org. matter; acidic soil & high rainfall lead to leaching

Savana

tropical seasonal forest

• warm temps & distinct wet & dry seasons

• fertile soils

Hot Desert

hot temps, extremely dry conditions & sparse vegetation

• small/modified plants like cacti, euphoria & succulents

Mod 3: Aquatic Biomes

Freshwater Biomes Includes

• streams

• rivers

• lakes

• wetlands

* have low salinity

Marine/Saltwater Biomes Includes

• estuaries

• coral reefs

• open ocean

Rivers & Streams

specifically characterized by flowing freshwater

• have high O2 due to flow mixing water & air, also carry nutrient-rich sediments

  (Deltas & flood plains = fertile soil)

• fast-moving streams tend to combine, forming rivers, which then slow down

• streams tend to have few plants & algae & when combined into a river, more sediments & org material settle so plant growth can occur

Lakes & Ponds

tend to have standing water & may be too deep to support vegetation

Littoral Zone

shoreline, shallow water w/emergent plants

Limnetic

sunlight penetration allows for photosynthesis

• no rooted plants, only floating algae/phytoplankton

Profundal

too deep for sunlight (no photosynthesis)

Benthic

murky bottom where inverts (Bugs) live, nutrient-rich sediments

Oligotrophic

lakes have low nutrients

Mesotrophic

lakes have moderate nutrients

Eutrophic

lakes w/high nutrients

• can have high concentrations of algae & block light due to high turbidity

Freshwater Wetlands

among the most productive biomes on the planet

• land that is saturated by water for at least part of the year, but swallowed enough to support vegetation

Include:

• swamps - contain emergent trees

• marshes - contain primarily non-woody vegetation

• bogs - very acidic wetlands that typically contain sphagnum moss & spruce trees

Marine Biomes

characterized by salt water

Include:

• estuaries/salt marshes (tend to be nurseries for fish/other organisms)

• mangrove swamps

• intertidal zones

• open ocean

Estuaries

near coast lines where rivers of freshwater & saltwater from the ocean combine

• high productivity (plant growth) due to nutrients in sediments deposited in by river

Salt Marshes

found along coast in temperate climates

• breeding ground for many fish & shellfish species

• contain non-woody emergent vegetation

Mangrove Swamps

characterized by mangroves w/roots that rise above water to survive high salt content

• mangrove trees w/long, stilt roots stabilize shoreline & provide habitat for many species of fish & shellfish

Intertidal Zones

narrow bands of coastline that exist btwn high & low tide

• high tide provides stable conditions

• low tide can become quite harsh exposing species to extreme temps & desiccation

• includes orgs like barnacles, sponges, algae mussels, crabs & sea stars

Coral Reefs

most diverse marine biome

• found in warm shallow waters beyond the shoreline in tropical regions

Coral Bleaching

the process where corals turn white after expelling the symbiotic algae that live in their tissues, losing their primary food source & color

* caused by a combo of factors such as

• decreased pH

• disease

• increased water temps

Open Ocean

so large that algae & phytoplankton of ocean produce a lot of earth’s O2 & absorb a lot of atmospheric CO2

Photic Zone

upper layer of the ocean receives enough sunlight to allow for photosynthesis

• contains algae & phytoplankton that produce a large amount of the planets O2

Aphotic Zone

lacks sufficient sunlight to allow for photosynthesis

• contains bacteria that can use energy contained in methane & hydrogen sulfide to produce energy through a process called chemosynthesis

Mod 4: The Carbon & Nitrogen Cycles

Reservoirs

sources of the element

Carbon Cycle

moves carbon through the atmosphere & biosphere

* carbon makes up abt 20% of organisms total body weight & found in cell walls (carbohydrates), proteins, & stored for later energy use (fats)

HUMAN IMPACTS:

• w/o human involvement the CC would remain in a steady state

• combustion of fossil fuels has led to an increase of CO2 in the atmosphere

• CO2 is the most abundant greenhouse gas that contributes the most to the warming of the atmosphere

• more CO2 is being released into the atmosphere than is being trapped by natural processes leading to increase global temps

Photosynthesis

plants & algae, and some bacteria use this process to convert CO2 & H2O into glucose & oxygen

* crucial process bc it removes CO2 from. the atmosphere + incorporates it into organic molecules, effectively acting as a carbon sink

Cellular Respiration

organisms convert glucose + oxygen into energy, releasing CO2 + H2O as byproducts (through aerobic resp + decomposition)

• performed by: plants + animals to release stored energy

Exchange

processes that transfer carbon btwn diff reservoirs, such as the atmosphere, oceans, land (including vegetation + soil) + fossil fuels

* btwn the atmosphere + ocean

Sedimentation

carbon-containing particles accumulate + settle in layers, typically at the bottom of bodies of water

• over long pds, these layers can turn into sedimentary rocks like limestone (formed from calcium carbonate shells of marine organisms) + fossil fuels

Burial

long-term storage of carbon in underground reservoirs, such as fossil fuels (coal, oil + natural gas) + sedimentary rocks

• happens when organic matter, like dead plants + animals, gets buried under layers of sediment + subjected to high pressure + heat over mills of yrs

Steady State

where the inputs of carbon equal the outputs of carbon

Extraction

driven by human use of fossil fuels like coal, oil + natural gas

• when these fuels r extracted + burned for energy, the carbon s released into the atmosphere as CO2, which can impact the climate

* abiotic process

Combustion

burning organic materials/fossil fuels in the presence of oxygen, which releases stored carbon into the atmosphere as CO2 (in fossil fuels, fires, or volcanoes)

• atmosphere is key carbon reservoir; increasing lvls can lead to global warming

Carbon Sink

reservoir that takes in more carbon than it releases

• leads to a lack of steady state

* abiotic process

Nitrogen

most abundant gas (N2) in our atmosphere 78% (atmosphere is the largest reservoir for it)

• used to form amino acids which in turn form proteins

• also used in the formation of nucleic acids which r the building blocks for DNA/RNA

• limits nutrient for plant + algal growth

Nitrogen Cycle

* abbreviation for the process: FixNAAD-ANPAN

HUMAN IMPACTS:

• being a limiting factor, humans have developed ways to create synthetic N2 + add it to fertilizers

• leads to leaching

Leaching

dissolved molecules transported to groundwater through the soil

Mod 5: The Phosphorus & Hydrologic Cycles

Phosphorous

crucial component of DNA, RNA + ATP, making it one of THE most limiting element to plant growth

• found in rocks + sediments containing minerals

Phosphorus Cycle

does not have an atmospheric phase

• bc of this, phosphorus travels slowly

• limiting nutrient in aquatic envs.

SYNTHETIC PROCESSES:

• use of fertilizers applied containing N2 + P to lawns, gardens + agricultural ields leads to excess P in bodies of water

• another source of excess P besides fertilizers is detergents, which has led to bans in P detergents

Weathering

breakdown of rocks + minerals that contain phosphorus, releases phosphate ions into soil + water (which can be used by plants + eventually make their way through the food chain)

Assimilation

plants absorb inorganic PO4³- from the soil/water through their roots. Once inside the plant, it is used to create essential organic molecules like DNA, RNA + ATP

• animals obtain P by consuming plants/other animals

Mineralization

organic P is converted into inorganic forms, such as PO4³-, typically occurs through the decomposition of plant + animal matter by bacteria + fungi. The released inorganic PO4³- then returns to the soil/water, where it can be used by plants, thus completing the cycle

Sedimentation

PO4³- precipitates out of soln + accumulates in sediments at the bottom of bodies of water like lakes + oceans

• over long pds, these sediments can turn into rock, effectively locking away P (this P may eventually be released back into the cycle through geological uplift + weathering)

Geologic Uplift

long-term process where tectonic forces raise the Earth’s crust, brining P-containing rocks from the ocean floor/deep soil layers to the surface

• once exposed, these rocks undergo weathering, which gradually releases po4³- into the soil + water, making it available for living orgs

Eutrophication

leads to dead zones

* use of fertilizers

• leads to algal blooms, increasing mass of algae in bodies of water

• the algae then die, + their decomp leads to a hypoxic (low-oxygen area) + then a dead zone, as orgs can’t survive in hypoxic conditions

* human + animal waste can also enrich water causing this

Water

• movement of H2O on our plane is powered by the sun

• H2O moves through reservoir resources + sinks called the hydrologic cycle

* ocean is our largest reservoir of water

* ice caps & groundwater r smaller reservoirs, but contain fresh, useabe water for humans

Hydrologic Cycle

• precipitation (rain)

• evaporation

• transpiration

• evapotranspiration

• runoff

• percolation

• infiltration

HUMAN IMPACTS:

• removal of trees can reduce evapotranspiration, which causes an increase in runoff + flooding

• creation of impermeable surfaces such as, w/concrete roads + parking lots, so water can’t get into the ground (leads to flooding/high forms of erosion)

Precipitation

recharges groundwater through infiltration, but only if ground is permeable (able to let water pass through)

Transpiration

process used by plants to draw groundwater from roots up to their leaves. Leaf openings (stomata) open, allowing water to evaporate into the atmosphere from leaves

Runoff

flow of water over earth’s surface into streams + rivers. Recharges surface waters, but can also carry pollutants into water sources

Percolation

where water moves downward through the soil + rock under the influence of gravity

• this movement helps to replenish groundwater aquifers, which r underground layers of water-bearing permeable rock/soil

Mod 6: Primary Productivity

Primary Productivity

the amount of plant growth in an area over a given pd of time

• rate at which solar energy (sunlight) is converted into org compounds via photosynthesis over a unit of time

* begins w/producers/autotrophs, or plants, algae + bacteria

• has low efficiency bc conversion of sunlight into chem energy is not efficient

Gross Primary Productivity

measure of energy from the sun converted by photosynthesizers

• total rate of photosynthesis in a given area

* rate of photosynthesis can measured by: CO2 taken up during photosynthesis = CO2 taken up in sunlight + CO2 produced in the dark

Net Primary Productivity

rate of energy storage by photosynthesizers in a given area, after subtracting the energy lost to resp

• energy captured by producers in an ecosystem minus the energy they use for resp

  * formula: NPP = GPP - Resp by producers

• can be quantified in kcal/m²/yr + in kg C/m²/yr measuring energy + biomass

• NPP of most ecosystems range from 25%-50% of GPP

* factors that lead to high NPP: water availability, higher temps + nutrient availability

Biomass

the total mass of all living matter in a specific area

Standing Crop

total amount of living orgs (biomass) in a specific area/ecosystem at a particular time

Mod 7: Trophic Levels, Energy Flow + the 10% Rule, Food Chains + Food Webs

Trophic levels

successive lvls that make a food chain

• algae + plants - produce energy

• consumers/heterotrophs - obtain energy through consumption of others

• herbivores/primary consumers

• carnivores/secondary consumers - consume herbivores

• tertiary consumers - eat carnivores

Scavengers

consume dead animals

Detritivores

eat + break down dead tissue + waste

Decomposers

fungi + bacteria that chemically break down org matter

Ecological Efficiency

proportion of consumed energy passed from 1 trophic lvl to another

• tends to be anywhere from 5%-20%, w/an avg of 10% (10% rule)

* can be applied to the human diet (if all humans were to eat at a lower trophic lvl, there would be less need for farmland)