A group of organisms sharing common characteristics that can be interbred to produce offspring that can interbreed.
What are the limitations of the species concept?
Doesn’t account for asexually reproducing organisms.
Doesn’t classify species in extinct populations.
Doesn’t identify whether isolated populations belong to the same species.
What are autotrophs?
Organisms that are capable of producing their own organic molecules as a source of food.
Autotrophs take light energy and turn it into chemical energy.
What are heterotrophs?
Organisms that can’t produce their own food and depend on chemical energy obtained by consuming autotrophs or other heterotrophs.
What are detritivores?
Larger decomposers like earthworms, woodlice and beetles.
What are saprotrophs?
Fungi and bacteria that externally digest dead matter (detritus).
What are communities?
A community is a group of populations living and interacting with each other in a given area.
What are abiotic factors?
Salinity (Non-living, physical factors)
What is environment?
The external surroundings that affect species’ survival and development.
Explain the nitrogen cycle.
Without this element, organisms would not be able to make DNA or proteins, and thus life would be impossible. Nitrogen starts the cycle in gas form in the atmosphere, as N2. Plants and animals are incapable of using nitrogen gas but some bacteria are able to transform it into useful forms, such as nitrates, in a process called nitrogen xation. These usable nitrates are absorbed by plant roots (which is why some plants host the nitrogen fixing bacteria in their root nodules.
What is a habitat?
The environment in which the species lives.
Food chain example:
diatoms → copepods → herring → seals → great white shark
What is a food chain?
A a sequence showing the feeding relationships and energy flow between species.
What is an ecosystem?
A community and the physical environment it interacts with.
What is the second law of thermodynamics?
Energy and biomass decrease along the food chain due to loss to heat.
Why is there energy loss from one trophic level to another?
The entire organism is not consumed, so will be left to decay or will be excreted.
Some organisms die without being consumed by the next trophic level.
Cellular respiration, movement and warm blooded animals maintaining body temperature results in considerable heat loss.
Explain carbon in ocean.
Co2 is absorbed by the ocean where it reacts with water to form HCO3, which decreases the pH of oceans.
Explain methane in the carbon cycle.
Methanogens produce CH4 when they metabolize food, since there is no oxygen where they live. (cow digestive tract)
CH4 is natural gas, and when oxidized, it releases CO2 and H20 in the air. When we oxidize CH4 and release CO2, we contribute to the carbon cycle. However, the accumulation of CH4 is very slow, and it’s burning, very rapid.
What is peat?
It’s an organic substance composed of partially decomposed leaves that can be used as a fossil fuel. Due to anaerobic conditions within the peat, the energy rich molecules inside, which are not able to be decomposed, turn into energy-rich peat.
Peatlands provide a habitat for unique species. Peatlands contain pollen from thousands of years ago, which is beneficial for climatology.
How does coal form?
Sediment accumulates on top of peat, increasing pressure and heat. Lithification occurs as each CH bond contains high amounts of energy.
How does oil form?
Partially decomposed zooplankton and algae formed sludge and kerogen (lipids that could not be easily decomposed) when exposed to high amounts of heat and pressure.
Cow dung is enclosed as its anaerobic decomposition creates CH4.
Plant material is fed to ethanol producing organisms. Ethanol is mixed with petroleum, which reduced petroleum use.
Biodiesel is made from vegetable oils (used).
What is limestone?
While building shells, some animals trap the HCO3 in the water to make CACO3 (limestone)
Limestone is removed from the ocean floor and used as building material (cement). During the process, some of the carbon that was captured by thousands of years is rapidly released into the atmosphere.
Up and down fluctuation in carbon level in the atmosphere in one year is caused by..
Rate of photosynthesis changing throughout seasons.
What is the preventive principle?
The action must be proven to not be harmful before it is taken. If there is question about GHG caused global warming, companies must immediately stop rapid fossil fuel use until it is proven to not be harmful to avoid catastrophes.
What causes enhanced Greenhouse effect?
Rapid population growth and associated consumer demand for transportation and industry
Deforestation of tropical rainforests.
Methane release due to cattles and rice patties.
Criticism: fossil fuel uses are increasing, why aren’t temperatures increasing equally as fast?
Some particles released in industry diffuse short wave radiation and decrease temperatures.
Even weather forecasts show a degree of uncertainty.
Criticism: There is disagreement within the scientific community.
There is consensus within the scientific community that anthropogenic climate change is real. Some scientists use out of date or refuted data.
Criticism: There have always been fluctuations in climate. For example, the sun is in a phase of high energy now.
The hottest years occurred during low solar energy phases.
Climate change and extinction rates at this rates are unprecedented.
Criticism: Carbon based industries will lose revenue.
The cost of avoiding climate change is worth the benefits of it.
Challenge from a critic: climate change is just a theory, not a fact.
Evidence clearly shows temperature increases since the industrial revolution. Dinsings are analyzed by IPCC, which ensures the objectivity of the results. A scientific theory is a well-substantiated explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experiment. Such fact-supported theories are not "guesses" but reliable accounts of the real world.
Why do temperatures rise before CO2 levels rise?
Closer inspection of the data shows that the increase in temperature (in blue) happens rst and then the carbon dioxide concentration (in red) rises. This lag time is partly explained by the fact that, as oceans warm up, they release carbon dioxide, because gases dissolve less well in warm water than in cold water. A positive feedback loop leads to further increases in temperatures over time: warmer temperatures → more carbon dioxide → even warmer temperatures → even more carbon dioxide, and so on.
What affects a GHG’s ability?
Its concentration in the atmosphere
Its ability to absorb long-wave radiation (heat)
Carbon is more concerning that NO and CH4 that actually have more global warming potential because of its concentration in the atmosphere. (35 percent increase since 1750)
Explain Pyramid of Productivity.
Flow of energy through each trophic level of a food chain over a period of time
Always pyramid due to second law of thermodynamics (kJ m–2 yr–1)
What is the role of a GHG?
GHGs have the ability to absorb and radiate infrared radiation (heat). When such gases are present, they keep the atmosphere near Earth’s surface warm by absorbing heat from the warmed surface and re-radiating it in all directions, including back down towards the surface. In addition to carbon dioxide and water vapour, methane and nitrogen oxides also contribute to Earth’s greenhouse effect, but to a lesser extent.
Short wave radiation can enter the atmosphere, however, GHGs block long wave radiation (infrared) reflected from the Earth’s surface and absorb it. The greenhouse gases can then re-radiate the heat in all directions, the way a radiator does in a cold room. Some of this heat will be lost to space, but some of the long-wave radiation will be directed down to the surface, keeping it warm. The rest will radiate within the atmosphere, preventing it from getting extremely cold at night when no more sunlight is present. When the Sun rises again in the morning, the surface will heat up and the whole process starts again.