Numbers of Insects (Species and Individuals) It has long been recognized and documented that insects are the most diverse group of organisms, meaning that the numbers of species of insects are more than any other group. In the world, some 900 thousand different kinds of living insects are known. This representation approximates 80 percent of the world's species. The true figure of living species of insects can only be estimated from present and past studies.
Retaining Wall Cost. Poured retaining walls with elaborate curves require complex formwork and will drive up cost for a wall. The total cost to have a concrete retaining wall installed will be a combination of material and labor prices. For a basic wall you can expect to pay between $30 and $40 per square foot.If you add a decorative finish, curves, steps, lighting or other upgrades, the cost will rise.or Ralston, $39 per square foot is the average cost he charges for a wall under 4 feet tall. For walls below 4 feet, he says his prices are often competitive with finished block. A block wall has to be stuccoed or finished with veneer, while a concrete wall does not need an added finish.
Labor costs will vary depending on the company you hire. Some companies have reusable concrete forms to build walls and this keeps their costs down. These companies typically charge about $3 to $5 per square foot of wall (disregard thickness of the wall).Other companies build concrete wall forms from scratch for each job and this drives cost slightly higher.n home construction, poured concrete walls are, normally, installed below grade. They are found in a basement, or in a split-level house that has a 3 to 4 foot high retaining wall, on top of which the rest of the house sits.