30 MILLION YEARS OF
EVOLUTION IN 12 WEEKS
While it took prehistoric fish some 30 million years to emerge
from the sea and start the evolutionary process that has made
us the rulers of the Earth, frogs usually complete the transition
from water to land in about 12 weeks, going through the three
stages of egg, larva, and adult. The female first lays clumps
of eggs that the male fertilizes. As the eggs mature, each yolk
divides repeatedly and begins to take on the form of a tadpole.
The eggs will start hatching about one to three weeks later.
Once the tadpoles are old enough to swim on their own, they
feed on algae and other vegetation as they develop legs and
an appetite for larger plants and insects as they grow. By the
time 12 weeks have passed, the tadpole’s tail and gills have
entirely disappeared and it has become an adult, now ready
to venture onto dry land.BETWEEN TWO
WORLDS
How long a frog will spend as a tadpole
depends on the species. While many make
the transition in about 12 weeks, bullfrogs
can take more than a year. Environmental
factors such as water temperature and
the degree of crowding also play
an important role.ideasanddiscoveries.com 15 May 2020