The Living World: Ecosystems

individual

one individual organism, which is a living thing

example: a singular elk

population

a group of organisms that are all of the same species

example: a herd of elk

community

all the living organisms in a given area

example: tress, a herd of elk, and a beaver

ecosystem

all living and nonliving things in a given area

example: plants, animals, rocks, soil, water, and air

biome

a large area that shares a combination of average yearly temperature and precipitation, or, simply, it shares a climate; the community of organisms within a biome are uniquely adapted to live in that biome

examples: desert, low amounts of precipitation and a high yearly average temperature; cacti and camels are uniquely adapted to have water-preserving traits

latitude

distance away from the equator

biome characteristics

tundras and boreal forests are more likely to be found in higher latitudes (commonly 60° or higher); temperature biomes are found in the mid-latitudes (around 30° to 60°); tropical biomes are closer to the equator

biome shifting

the ability of biomes to shift in location as the Earth’s climate changes

example: as area that has tundra warms, boreal forests will spread to that area as the permafrost soil melts and the boreal trees are now able to grow

mutualism

a relationship between organisms that benefits both organisms involved

example: coral reefs interacting with photosynthetic algae to form the coral reef-ecosystem, where coral provides reef structure and carbon dioxide for algae and the algae provides sugar for coral to use as an energy source

commensalism

a relationship in which one organism benefits and the other organisms isn’t impacted

example: barnacles attaching to whales, as the barnacles gain shelter and transportation whilst the whales neither gain nor lose anything

parasitism

a relationship in which one organisms benefits and the other organisms is harmed

example: tapeworm

predation

one organism using another as an energy/food source

examples: hunters, parasites, or herbivores

herbivores

organisms that eat plants for energy

carnivores

organisms that kill and eat prey for energy

parasites

organisms that use a host organism for energy, often without killing the host and often while living inside the host

parasitoids

organisms that lay eggs within a host organisms, and once the eggs hatch the larvae eat their way out of the host (commonly killing the host organism)

competition

organisms fighting over a shared resource like food and shelter, which limits population size

resource partitioning

different species using the same resource in different ways to reduce competition

temporal partitioning

using resources as different times of the day

example: wolves and coyotes hunting during different parts of the day

spatial partitioning

using different areas of a shared habitat

example: one tree utilizing a deeper root system (reaches deeper parts of the soil) while another uses a shallower root system (reaches shallower parts of the soil)

morphological partitioning

using different resources based on different evolved features

example: the finches that Darwin examined had larger beaks if they ate seeds and smaller beaks if they hunted insects, to minimize competition

characteristics of aquatic biomes

salinity, depth, flow, and temperature

salinity

how much salt is in a body of water, and it determines can survive and the usability for drinking such water

example: fresh water biomes vs. estuaries that have a higher salt content

depth

influences how much sunlight can penetrate and reach plants below the surface for photosynthesis

flow

determines which plants and organisms can survive, as a faster flow would allow for more oxygen gas to be dissolved in the water

temperature

warmer waters require specialized organisms as it holds less dissolved oxygen gas, and thus can support fewer aquatic organisms

rivers

a freshwater source that has high levels of oxygen due to the flow of mixing water and air, and can also carry nutrient-rich sediments because deltas and flood plains have fertile soil

lakes

standing bodies of fresh water, and are commonly used as a drinking-water source

zones of lakes and ponds

littoral, limnetic, profundal, and benthic

littoral zone

shallow water with emergent plants, such as reeds and cattails

limnetic zone

the zone where light can reach, but there are only phytoplankton (no rooted plants) in this zone

profundal zone

a zone too deep for light to reach

benthic zone

the murky, nutrient-rich bottom of lakes and bonds where bugs live

emergent plants

plants that have roots submerged in the water, but extend up and out of the surface of the water

examples: cattails, lily pads, and reeds

wetlands

a freshwater area with soil submerged or saturated with water for at least part of the year, but is shallow enough for there to be emergent plants

examples: cyprus trees are adapted to swamps; reeds are adapted to marshes; sphagnum moss is adapted to bogs

benefits of wetlands

• store excess water during storms and lessen floods

• recharge groundwater sources by absorbing rainfall into soil

• its plants filter pollutants from the water

• extremely diverse in plant growth due to lots of water and nutrients in sediments

estuaries

areas where rivers empty into the ocean, and thus have a mix of fresh and salt water

it is a high productivity aquatic biome as a result of nutrients in sediments deposited into estuaries by rivers

salt marsh

an estuary habitat along the coasts of temperate climates and are the breeding grounds for many fish and shellfish species

mangrove swamps

an estuary habitat along the coasts of tropical climates, where mangrove trees are uniquely adapted to the area with long, stilted roots (stabilizes the shorelines and provides habitats for species of fish)

coral reef

warm shallow waters beyond the shoreline; most diverse marine biome on Earth

intertidal zones

narrow bands of coastline between high and low tides; require organisms to be adapted to survive crashing waves and direct sunlight during low tide

shells and tougher outer skins can prevent desiccation

examples of organisms: barnacles, sea stars, rock-attaching crabs

dessication

the drying out of organisms as an effect of prolonged exposure to sunlight and heat

open ocean

low productivity per unit of area as a result of only algae and phytoplankton being able to survive in most of the ocean; the plants of the ocean produce a large portion of Earth’s oxygen and absorb large amounts of carbon dioxide

zones of the open ocean

photic and abyssal/aphotic zone

photic zone

an area within the open ocean where sunlight can reach

abyssal zone

an area within the open ocean that is too deep for sunlight to penetrate

carbon sinks

carbon reservoirs that store more carbon than it releases

examples: the ocean (algae and sediments), plants, soil

carbon sources

processes that add carbon to the atmosphere

examples: fossil fuel combustion, animal agriculture (releases methane), deforestation (releases carbon dioxide)

photosynthesis

a process that removes carbon dioxide from the atmosphere and converts it to glucose

organisms that utilize the process are plants, algae, and phytoplankton

glucose

the biological form of carbon and stores chemical energy in the form of sugar

cellular respiration

uses oxygen to break down glucose and release energy, but releases carbon dioxide as a byproduct

the process is done in both plants and animals, and it’s a carbon source

direct exchange

a process that moves carbon dioxide directly between the atmosphere and the ocean by dissolving into and out of ocean water at the surface

happens very quickly and in equal directions, balancing levels of carbon dioxide between the atmosphere and ocean

effects of fossil fuel combustion

fossil fuel combustion is a quick process that releases carbon

• increases atmospheric carbon amounts, leading to ocean acidification because of direct exchange

• strengthens the greenhouse effect, leading to overall higher temperatures on Earth

• releases carbon far faster than the process of burial, thus there is an overall net increase in the concentration of carbon dioxide in the atmosphere

sedimentation

the process by which marine organisms die and their bodies sink to the ocean floor where they’re broken down into sediments that contain carbon

burial

the compression of carbon-containing sediments on the ocean floor into sedimentary rock, over long periods of time

since it takes place over long periods of time, it’s a long-term carbon reservoir

fossil fuels

farmed from the fossilized remains of organisms

examples: dead ferns (coal), marine algae and plankton (oil), and natural gas

extraction

the digging up and mining of fossil fuels

combustion

the burning of fossil fuels as an energy source that quickly release carbon dioxide into the atmosphere

nitrogen sinks

processes that take in nitrogen from the atmosphere in increasing amounts

nitrogen sources

process that release nitrogen into the atmosphere

nitrogen in the atmosphere

the main nitrogen reservoir, storing nitrogen as nitrogen gas (which isn’t usable to plants or animals)

nitrogen

a critical nutrient for both plants and animals, however its reservoirs only hold it for relatively short periods of time (when compared to other cycles)

reservoir examples: plants, soil, atmosphere

nitrogen fixation

process of nitrogen gas being converted into forms usable by plants, including ammonia or nitrate

bacterial fixation

certain bacteria that live in the soil and convert nitrogen gas into ammonia

rhizobacteria

bacteria that live in root nodules of legumes (peas, beans, etc.) and fix nitrogen for them in return for amino acids from the plant, as they are in a mutualistic relationship

synthetic fixation

a human process that utilizes fossil fuels to convert nitrogen gas into nitrate

nitrate

a compound added to synthetic fertilizers and used in agriculture, but is fixed from nitrogen gas in a synthetic process

nitrogen assimilation

the process by which plants and animals take in nitrogen and incorporate it into their body

plants take in nitrogen through their soil, but animals have to eat plants or other animals

ammonification

the process by which soil bacteria, microbes, and decomposers convert waste and dead biomass back into ammonia and return it to the soil

nitrification

the conversion of ammonia into nitrite and then nitrate by soil bacteria

denitrification

the conversion of nitrate into nitrous oxide gas, which returns to the atmosphere

nitrous oxide

a greenhouse gas that warms the Earth’s climate

released through the tilling and clearing of lands, which triggers denitrification, and releases excess nitrous oxide into the atmosphere

ammonia volatilization

excess fertilizer use that leads to ammonia gas entering the atmosphere; can lead to acid precipitation and respiratory irritation in animals

leaching

synthetic fertilizer usage that leads to nitrates being carried out of the soil by water

eutrophication

a phenomenon that occurs as a result of excess nitrogen or phosphorus in waters, which fuels algae growth that then blocks sunlight to the point where aquatic plants are unable to conduct photosynthesis (effectively kills the plants)

eventually, the algae die and decomposers use oxygen to break down the algae, reducing the amount of oxygen in the water; this depletion of oxygen then kills marine animals like fish, and requires the decomposers to use up more oxygen in decomposing the dead animals

dead zone

a body of water that contains such little oxygen that no life can be supported there, commonly a result of intense eutrophication

phosphorus sinks

reservoirs that store phosphorus for periods of time; major ones are rocks and sediments that contain phosphorus minerals

causes of a slow phosphorus cycle

• takes a long time for minerals to be weather out of rocks and carried into the soil or bodies of water

• there is no gas phase of phosphorus, so it cannot enter the atmosphere

effects of a slow phosphorus cycle

phosphorus serves as a limiting nutrient, meaning that plants can only grow in ecosystems depending on phosphorus availability

natural source of phosphorus

rocks are weathered; then, wind and rain carries the rock and phosphate into bodies of water or nearby soils

synthetic source of phosphate

mining phosphate minerals and adding them to products like synthetic fertilizers and detergents

phosphorus fertilizer runoff

can result in excess phosphates entering bodies of water and lead to eutrophication

phosphorus assimilation

the process by which phosphorus is absorbed by plant roots and integrated into tissues; animals conduct this process by eating plants or other animals

decomposition

animal waste, plant matter, and other biomass is broken down by bacteria/soil decomposers, in an aerobic process, that returns the phosphorus back to the soil

geological uplift

tectonic plate collisions that force up rock layers that form mountains; enables the restarting of the phosphorus cycle by triggering weathering

water sinks

water reservoirs that store water in increasing amounts

examples: the ocean (largest), groundwater, ice caps, and the atmosphere

evaporation

the process by which water is transformed from a liquid to a gaseous state as a result of the Sun’s rays

transpiration

the process that plants use to draw groundwater from roots up to their leaves, via leaf openings called the stomata, that allows for water to evaporate into the atmosphere from the leaf

evapotranspiration

the total amount of water that enters the atmosphere from both transpiration and evaporation

runoff

the process of precipitation entering a body of water by flowing over the Earth’s surface

infiltration

the process of precipitation trickling through the soil into groundwater aquifers, which can only occur if the ground is permeable

primary productivity

the rate at which solar energy is converted into organic compounds via photosynthesis over a unit of time, or the rate of photosynthesis of all producers in an area over a given period of time

higher rates of this indicate more biodiversity in the ecosystem

respiration loss (RL)

the amount of energy that plants use, from what they generate via photosynthesis, by doing cellular respiration (movement, internal transportation, etc.)

gross primary productivity (GPP)

the total amount of sun energy, or light, that plants capture and convert to energy through photosynthesis

net primary productivity (NPP)

the amount of energy (biomass) left over for consumers after plants have used some for respiration

ecological efficiency

some ecosystems are more efficient (have a higher NPP) for a multitude of reasons

examples: an ecosystem could receive more sunlight, or their plants are able to do more photosynthesis, or they’re more efficient than other ecosystems

trends in NPP

• the more productive (higher NPP) a biome is, the wider the biodiversity is

• higher temperatures, and greater nutrient and water availability, lead to a high NPP

conservation of matter

matter is never destroyed, it only changes forms

first law of thermodynamics

energy is never created nor destroyed, it is only transferred or transformed

second law of thermodynamics

each time energy is transferred or transformed, some of it is lost as heat