Nestled at the edge of the arid Great Basin and the snowy Sierra Nevada mountains in California, Mono Lake is an ancient saline lake that covers over 70 square miles and supports a unique and productive ecosystem. The lake has no fish; instead it is home to trillions of brine shrimp and alkali flies. Freshwater streams feed Mono Lake, supporting lush riparian forests of cottonwood and willow along their banks. Along the lakeshore, scenic limestone formations known as tufa towers rise from the water's surface. Millions of migratory birds visit the lake each year.
From 1941 until 1990, the Los Angeles Department of Water and Power (DWP) diverted excessive amounts of water from Mono Basin streams. Mono Lake dropped 45 vertical feet, lost half its volume, and doubled in salinity.
The Mono Lake Committee, founded in 1978, led the fight to save the lake with cooperative solutions. We continue our protection, restoration, and education efforts today with the support of 16,000 members --and we host this Website.
In 1994, after over a decade of litigation, the California State Water Resources Control Board ordered DWP to allow Mono Lake to rise to a healthy level of 6,392 feet above sea level--twenty feet above its historic low. It is rising toward that goal -- click here for the current lake level, or visit one of the other links on this page for more of the Mono Lake story.
A cell that just fertilized has to divide 6 times to form a 64 cell blastomere.
<u>Explanation:</u>
Human reproduction begins with the fusion of male gamete sperm and female gamete ovum. The fusion of sperm and ovum forms the zygote that is diploid. The zygote then undergoes mitotic division to develop into embryo.
The zygote first divides into two and the two individual cells divide again to form four individual cells and so on. Thus the number of cells after each division can be represented by the equation 
where n is the number of divisions. in the question it is given that the blastomere has 64 cells.
n=6
This means that the fertilized cell has to divide 6 times to develop into 64-celled blastomere.
Bird migrations began with the recession of the glaciers during the ice age. You will notice a great increase in insects in the spring time and early summer.The birds moved North to take advantage of this increase in the food supply that followed the warming in the spring and early summer. Their reproductive organs temporarily developed so they could lay eggs and raise a family. Look at the early flush of Night crawlers in the moist times of the early rains. By mid summer most of the insects have matured, mated and died. Their eggs have hatched and turned to larva and moved underground until next spring. The shortening of the days causes the reproductive functions to decrease and signals the birds that the food will soon become scarce. They move back to the area that makes it the easiest to find food and avoid freezing. which of course is the warmer climates nearer the equator. Not all birds move past the Tropics at approximately 30 degrees. Some like Chickadees may move down from Mi or Mn or Canada only as far south as Indiana. Some migrations may be quite short. For example from the mountains down to the plains. They don't generally reproduce in the warmer winter climes they migrate to. In the spring time they migrate along paths of the retreating glaciers. As the climate warms away from the tropics the birds follow the emerging insects etc to the birds selected breeding grounds.with increased insects and longer days to feed the hatching's. It is necesary to understand why they move to cooler climates in the summer to under stand why they move to eh warmer ones in the fall. As the days shorten the food supply dwindles and the babies have fledged. They move to warmer climates in winter to rest and refuel for the next years migration.
