unit 4 Flashcards
define specie
A group of organisms that can potentially interbreed to produce fertile, viable offspring.
Organisms that live in different populations still count as species if interbreeding is possible.
define population
A group of organisms of the same species that are living in the same area at the same time.
define community, habitat, abiotic, biotic and ecosystem?
community:A group of populations living together and interacting with each other within a given area
habitat: Environment in which a species lives
abiotic: Non-living
bioitc: Living
ecosystem: A community and its abiotic environment
explain Reproductive isolation
Autotroph
3 groups of autotrophs
Obtains inorganic molecules from abiotic environment
Synthesizes own organic molecules from simple inorganic substances like CO2
Commonly called producers
Plants, algae, cyanobacteria
Heterotroph
Obtains organic molecules from other organisms
Commonly called consumers
Herbivores feed principally on plant matter (e.g. cows, sheep, rabbits)
Carnivores feed principally on animal matter (e.g. crocodiles, wolves, tigers)
Omnivores eat both plant and animal matter (e.g. pandas, humans)
Scavengers
Scavengers feed on dead and decaying carcasses rather than hunting live prey (hyenas, vultures, crows)
Detritivores
Detritivores obtains nutrients from non-living organic sources
- digest internally
Saprotrophs
Live on/in non organic matter, secrete digestive enzymes into it and absorb products of digestion
Feed by external digestion unlike everyone else
Decomposers - mostly bacteria and fungi
Outline the generalized flow of nutrients between the abiotic and biotic components of an ecosystem.
Elements like carbon, nitrogen, oxygen, and hydrogen are moved through biotic components of an ecosystem through food chains and recycled through abiotic environments including the atmosphere, water, and soil
Define sustainability
3 requirements of a sustainable ecosystem
Capacity of ecosystems to maintain their essential functions and processes over time
Nutrient availability, energy, and ability to detoxify waste products
Define food chain and food web
Meaning of arrow in food web/chain
Food chain: sequence of organisms through which energy and nutrients pass as one organism eats the other
Food web: interconnected feeding relationships within an ecological community
Represent flow of energy + nutrients between trophic levels
Outline the flow of energy through a food chain
Light energy is converted to chemical energy by autotrophs, stored in carbon compounds
Energy is transferred from organism to organism through feeding
Aprox. 90% of energy is lost between every trophic level (either because it’s unconsumed or lost as heat/fecal matter)
Energy is not recycled
Biomass
Mass of living organisms in a given area at a given time
Trophic level
Group of organisms in ecosystem occupying the same position on a food chain (producer, primary consumer, secondary consumer, tertiary consumer… decomposer)
Average amount of energy passed through each level of a food chain
10%
Describe shape of a pyramid of energy
Top trophic level is the smallest, only part of the energy of one trophic level will become part of the next trophic level
Outline the process that converts CO2 to hydrogen carbonate ion in water
CO2 is diffused in water. Some will remain as dissolved gas, the remainder will combine with water to form carbonic acid (H2CO3) which dissociates to form hydrogen ions and hydrogen carbonate ions (H+ and HCO3-)
The increased H+ concentration in water will reduce its pH, making it more acidic
Role of diffusion in carbon cycle
CO2 diffuses into autotrophs from atmosphere/water = carbon source for photosynthesis
CO2 diffuses out of living things back to atmosphere/water because it’s a waste product from cell respiration
Outline the role of methanogenic archaea in the transformation of organic material into methane
Methanogenic archaea are microorganisms that produce methane as metabolic byproduct in anaerobic respiration, which will either be diffused in the atmosphere as greenhouse gas or accumulate underground
Oxidation of methane
Methane is oxidised (loses hydrogen) to form CO2 in the atmosphere
CH4 + 2O2 → CO2 + 2H2O
Formation of peat
Brown deposit resembling soil
Formed when organic material doesn’t fully decompose
Formed in acidic/anaerobic conditions where decomposers are inhibited
Formation of coal
Forms from peat over long time periods
Heat + pressure produce physical + chemical changes in peat levels, forcing out oxygen and leaving rich carbon deposits (coal)
Formation of oil + natural gas
Dead microscopic plants + animals sink to bottom of sea floor. Over time, layers of sediments formed on top = heat + pressure began to rise, forms gas/oil which deposits in surrounding rock
Coral + molluscs shells
Hard shells like molluscs and coral are made of calcium carbonate (CaCO3)
When organisms die these components may be fossilized in limestone
Lithification
Compaction of sediments into rocks
Formation of limestone
Composed of calcium carbonate, is an organic sedimentary rock from the accumulation of shell, coral, etc. in water
Carbon flux + processes
Unit of measure for carbon flux values
Exchange of carbon between Earth’s carbon pools (locations that take in + release carbon, like biosphere, hydrosphere, geosphere, atmosphere)
Photosynthesis, respiration, decomposition, diffusion, lithication, combustion, fossilization, feeding
Gigatonnes
Greenhouse gases in atmosphere
Water vapour, carbon dioxide, methane, nitrogen oxides
Water + CO2 are most abundant
Sources of nitrous oxide + methane in atmosphere
Nitrous oxide - agriculture, fuel combustion, industrial processes, cars, nitrogen cycle
Methane - methanogens in ruminants (cattle) and wetlands
Greenhouse effect
Natural process by which radiation (heat) is trapped in atmosphere, warming its surface to temperatures needed for life + prevents rapid temperature fluctuations (like at night with no sunlight)
Mechanism by which gases trap heat in atmosphere
Surface of Earth absorbs short wave radiation from sun + re-emits it into atmosphere at longer wavelength, greenhouse gases absorb that radiation and radiate it back to surface
Ice core data
Earth’s climate can be studies up to 800 000 years back by drilling in ice sheets in Antarctica and Greenland, info about CO2 concentrations is trapped in there
