Describe how fish kills in estuarine systems can result from algal blooms.
Algae is a photosynthesizing organism. The primary nutrients required of photosynthesizing organisms (plants) are nitrogen and phosphorous. It's no coincidence that the key components of fertilizers are nitrogen and phosphorous. When fertilizers run off into estuarine bodies of water, algae thrive in abundance to produce algal blooms. The algae, like all living things, eventually die. When this overabundance of algae die, bacteria thrive as they decompose the dead organic matter. Bacteria are respiring organisms and thus require oxygen to respire. As they decompose the dead algal matter they consume the oxygen in the water. In turn, there is no oxygen in the water column to move over the fishes gills (fish also need oxygen and they acquire it through water movement over their gills). The lack of oxygen can result in large fish kills.
What is the difference between a single replacement reaction and a double replacement reaction?
A single replacement reaction is a chemical reaction that takes place between an ionic compound and an element. They will recombine to form a new ionic compound and a new element. i.e. AB + C --> AC + B A double replacement reaction takes place between two ionic compounds. The cations in the ionic compounds switch places to form two new ionic compounds. i.e. AB + CD --> AC + BD
Homo sapiens (humans) have a total of 46 chromosomes. What is the haploid and diploid number for this species?
Humans have a haploid number of 23. This means that after undergoing meiosis, the resulting sex cells have a total of 23 chromosomes, half the number of a somatic cell (body cell). This enables the sex cell, either the sperm or ova, to combine with the opposite sex cell to form a diploid offspring. Diploid cells, on the other hand, make up the vast majority of a human being's body cells. These cells are considered diploid and have a diploid number of 46.