1 Coelomate animals or Coelomata (also known as eucoelomates â true coelom) have a fluid filled body cavity called a coelom /ËsiËlÉm/ with a complete lining called peritoneum derived from mesoderm (one of the three primary tissue layers).he coelom allows muscles to grow independently of the body wall â this feature can be seen in the digestive tract of tardigrades (also known as water bears) which is suspended within the body in the mesentery derived from a mesoderm-lined coelom.
At a 3 percent growth rate, its doubling time â or the number of years to double in size â is 23 years. (The doubling time for a population can be roughly determined by dividing the current growth rate into the number 69. Therefore, 69/3=23 years. Of course, if a population's growth rate does not remain at this rate, the projected doubling time would need to be recalculated.)
6Population 2050: The global population is expected to increase by 38%, from 6.9 billion in 2010 to 9.6 billion in 2050. The population of children younger than 15 is projected to increase by only 10%, a consequence of falling birth rates.