IB HL BIO MIDTERM

Ecosystem

multiple communities interacting with their nonliving environment, biotic & abiotic factors in an area

Deforestation

the action of clearing a wide area of trees, mostly for farm land, reduces amount of photosynthesis occurring -> less CO2 absorbed

Tipping Points

The critical threshold of a change that results in a significant and often irreversible change in an ecosystem’s structure, function or composition

Percentage Change

[ (final-initial) / initial ] x 100

Mesocosm

used in ecological research to allow scientists to investigate a variety of issues, create conditions that mimic possible changes in climate and see how it impacts ecosystem

Keystone Species

species that have a disproportionately large impact on the community compared to their abundance or biomass, presence or absence deeply affect the stability of the ecosystem

Sustainable Harvest

the rate of harvesting is lower than the rate of replacement

Sustainable Fishing

harvesting fish at a sustainable rate so that the fish population doesn’t decline over time, uses selective methods to maximize fish capture without fish populations declining

Maximum Sustainable Yield

largest harvest that can be sustained over time without a decrease in population

Eutrophication

the process of water bodies become enriched with excessive nutrients (nitrogen & phosphorus), leads to an overgrowth of algae & etc aquatic plants, can disrupt balance of ecosystem

Biological Oxygen Demand (BOD)

the amount of dissolved oxygen consumed by aerobic bacteria growing on the organic material present in a water sample, increases with higher populations of aerobic bacteria

Bioaccumulation

the gradual buildup of chemical substances in the tissues of organisms over time

Biomagnification

the increase in concentration of the pollutant in the tissues of organisms at successively higher levels in a food chain

DDT

insecticide, gradually biomagnifies, has larger impact on birds of prey (osprey) because it weakens egg shells

Minamata Disease

neurological disease caused by biomagnification of methylmercury in an ecosystem, first discovered in japan

Microplastics

produced by physical breakdown of big pieces, > 1 mm across

Macroplastics

large, visible debris, < 1 mm across

Biodegradable

capable of being decomposed by bacteria or other living organisms, doesn't cause pollution over time

Non-Biodegradable

not capable of being decomposed by bacteria or other living organisms, stays around for forever, causes pollution

Apex Predator

a predator at the top of a food chain, without natural predators of its own, highest trophic level, typically also keystone species

Rewilding

an approach to conservation & ecosystem restoration
involves reintroducing & restoring natural processes to ecosystems

Wildlife/Living Corridors

connects two habitats that have been separated (typically by roads), increases biodiversity, makes habitats more resistant to change, allows migration, expands habitat range

Climate Change

long term shifts in temperature and weather patterns

Anthropogenic

caused by humans

Global Warming

overall rise in temperature over decades in the entire world

Correlation

a mutual relationship or connection between two or more things

Positive Correlation

a relationship between two separate variables that move together in the same direction

Negative Correlation

a relationship between two separate variables that move together in different directions

Causation

one event is the result of the occurrence of the other event

Positive Feedback Loop

a change in a given direction causes additional change in the same direction

Decomposition

the process by which dead organic substances are broken down into simpler organic or inorganic matter

Permafrost

a permanently frozen layer on or under Earth's surface, very good carbon sink, when it melts -> releases CO2 into the atmosphere

Boreal Forest

carbon sink, contains more carbon in its soil because it is too cold to decompose quickly, may be near tipping point & become a carbon source (trees stop photosynthesis at high temperatures → absorbing less carbon → trees die and decompose)

Taiga

at a tipping point, trees are trying to move north to be in a colder climate, can't keep up with rapid rising temperatures

Carbon Sink

absorb more carbon than it emits

Sea Ice

ice formed from salt water

Landfast Ice

ice formed on land from fresh water and snow

Ice Floe

large stable masses of free floating ice

Nutrient Upwelling

the process by which cold nutrient-rich waters rise to the surface of the ocean, crucial mechanism for the supply of essential nutrients to upper layers of the ocean, impacted by changing ocean currents and wind (climate change)

Poleward Range Shift

movement towards poles, ex

Upslope Range Shift

movementent higher up in the atmosphere

ex- move up a mountain to get to colder temperatures

Coral Reef

an underwater ecosystem characterized by reef-building corals, contain about 25% of all marine life, very biodiverse

Mutualism

association between organisms of two different species in which each benefits

Ocean Acidification

the ocean’s pH is decreasing as more CO2 is diffused into the ocean, more hydrogen ions break up the CaCO3 in coral

pH

lower = more acidic, higher = more basic

Coral Bleaching

rising temperatures stress corals, corals release zooxanthellae (lose food & color source), don't die instantly but will eventually die of starvation

Afforestation

establishment of forests where there wasn't one previously

Carbon Sequestration

process of capturing and storing CO2 from the atmosphere, causes formation of carbon sinks, can be natural or anthropogenic, most efficiently done by forests

Peat

organic matter, not fully decomposed because of either an acidic environment and/or anaerobic conditions in water logged soils

Biodiversity

the variety of life in the world or in a particular habitat or ecosystem

Ecosystem Diversity

variety of ecosystems found in an area or on the planet

Species Diversity

number and relative abundance of species found within an ecosystem

Genetic Diversity

variety of genes and alleles present in a species
higher ____ = more likely to survive changes to the environment

Species

a group of organisms that can reproduce with one another in nature and produce fertile offspring

Anthropogenic

caused by humans

Habitat

the natural home or environment of a plant, animal, or other organism

Pollution

chemicals, particles, or other materials are released into the environment, are harming the organisms there

Overexploitation

when a living resource is removed from the environment at a rate faster than it can be replaced

Invasive Species

species introduced into new environments by humans (accidentally or deliberately), disrupt existing food chains, reproduce quickly, spread aggressively, outcompete native species

Deforestation

the action of clearing a wide area of trees, mostly for farm land, reduces amount of photosynthesis occurring -> less CO2 absorbed

Agriculture

the science of raising plants and/or animals for food, clothing or other useful products, he practice of cultivating the land or raising stock

Richness

number of different species in a particular area

Evenness

how close the population numbers of various species are to each other

Simpson’s Diversity Index

D = 1 - ((∑ n(n-1)) / (N(N-1))), D = diversity, higher means more diverse, N = total number of organisms, n = number of organisms in a particular species

Citizen Scientists

a member of the general public who collects and analyzes data relating to the natural world, typically as part of a collaborative project with professional scientists

Urbanization

the process of making an area more urban

Ex Situ Conservation

the process of protecting an endangered species, variety, or breed of plant or animal outside its natural habitat

In Situ Conservation

the process of protecting an endangered species, variety, or breed of plant or animal inside its natural habitat

Seed Bank

stores seeds to preserve genetic diversity

Nature Reserve

a tract of land managed so as to preserve its flora, fauna, and physical features

Rewilding

an approach to conservation & ecosystem restoration, involves reintroducing & restoring natural processes to ecosystems

Evolutionarily Distinct

the things that distinguish two species, the point at which two species become different and no longer to reproduce, happens through evolution

Globally Endangered

a species is in danger of extinction throughout all or a significant portion of its range

Autotrophs

primary producers, organisms capable of synthesizing organic molecules from inorganic ones that can be broken down into atp

Photosynthesis

process that takes atmospheric carbon and synthesizes organic molecules, takes in carbon

Photoautotrophs

organisms that synthesize organic molecules from atmospheric carbon and sunlight through photosynthesis

Chemoautotrophs

live in sunlight-limited environments, deep-sea hydrothermal vents, obtain energy through oxidation of inorganic compounds

Heterotrophs

an organism that eats other plants or animals for energy and nutrients

Food Chain

models that illustrate the transfer of energy/biomass, can't fully capture the complexity of feeding relationships, typically only 4-5 trophic levels long, amount of available energy decreases going up food chain because of inefficient energy conversions

Food Web

models that consist of many interconnected food chains, more complete description of complexity of transfer of energy/biomass

Consumers

cant produce own organic molecules and rely on consuming other organisms/organic matter to obtain energy/nutrients, use internal digestion (ingestion of food and then digestion)

Biomass

the total quantity or weight of organisms in a given area or volume

Organic Matter

matter composed of organic compounds that have come from the feces and remains of organisms such as plants and animals

Decomposers

break down dead organisms and organic matter, extract energy/nutrients from decaying materials such as leaf litter, wood, carcasses, and feces,

Saprotroph

obtain organic nutrients from dead organisms through external digestions, secrete hydrolytic enzymes to break down complex organic compounds into simpler ones then absorb and assimilate the nutrients into own body tissues

Detritivores

decomposers that obtain nutrients from detritus by internal digestions

Primary Consumer

herbivores/omnivores, transfer energy from producers to higher-level consumers

Secondary Consumer

feed on primary consumers, carnivores

Tertiary Consumer

animals that eat the secondary consumers in a food chain, carnivores, typically apex predators/keystone species

Trophic Levels

represents an organism's position in a food chain/web

defines its role in energy transfer

Energy Pyramid

diagram to represent amount of energy available at each trophic level, indicates the amount of energy units per area per time (kJ m-2 year-1)

Primary Productivity

rate at which producers accumulate carbon compounds in their biomass, measured in m-2 year-1, varies by region and season, more sun/water/ nutrient-rich soil means higher primary productivity

Secondary Productivity

rate at which consumers accumulate carbon compounds as a part of their own biomass

Carbon Sink

reservoirs that store carbon, any environment that absorbs more carbon dioxide from the atmosphere than it releases, essential for counteracting greenhouse gas emissions

Carbon Source

locations/processes that release more carbon into the atmosphere than they absorb
contribute to the increasing levels of atmospheric carbon dioxide

Carbon Flux

movement of carbon through the atmosphere

Respiration

carbon goes from producers to atmosphere, carbon source

Feeding

carbon goes from producers to consumers or consumers to other consumers

Natural Combustion

carbon goes from producers to atmosphere

Combustion of fossil fuels

producers are fossilized and then burned, carbon goes to atmosphere