SciHawks

Bio - We discussed some of the ways that humans impact the environment:by over-hunting and over-fishing, humans have caused the extinction of various species: the dodo-bird, the QUAGGA, one of Africa's most famous extinct animals, was a subspecies of the plains zebra, which was once found in great numbers in South Africa's Cape Province and the southern part of the Orange Free State. It was distinguished from other zebras by having the usual vivid marks on the front part of the body only. The Tasmanian Tiger was hunted to extinction in 1936. The sea cow grew up to 7.9 meters (25.9 ft) long and weighed up to three tons, much larger than the manatee but is now extinct.By burning fossil fuels, carbon dioxide concentration in the atmosphere increases and can contribute to the greenhouse effect. Also oxides of sulfur and nitrogen, from burning coal and other fuels, can react with water in the air to form acids, which produce acid rain that changes the abiotic factor, pH, of aquatic biomes. This can upset a stable ecosystem.We discussed various ways that humans can negatively impact ecosystems. From deforestation, which reduces the producer/autotroph level of organisms and can cause ecosystem instability, to monoculture farming, the planting of a single type of crop that can deplete the nutrient-rich layer of topsoil of the same essential nutrients so that the soil becomes less and less fertile for plants, we gave several examples of some of the negative effects that humans can and do cause.


We further discussed specific negative impacts on the environment such as water pollution via dumping of sewage, heavy metal ions, and other toxic chemicals.
We focused on the phenomenon of BIOMAGNIFICATION, the increase in CONCENTRATION of a substance that cannot be broken down by enzymes/metabolic activities. These substances increase in concentration as they get passed on to subsequent consumer levels in a food chain because there is a decrease in the total biomass of each level (most of the mass consumed gets excreted or burned up via respiration).
We then focused on several exotic/imported/INVASIVE species:
 purple loosestrife, brown tree snakes, the rhinohorn beetle, and zebra mussels.

We then did the next comparative anatomy step in our evolution/biodiversity lab.

AP Chem- took measurements to determine the Ksp of magnesium hydroxide.