What is Speciation Video Lecture - Class 10

[Music]
why are the animals in Australia so
unique
you've got the kangaroo in wallaby
marsupials that carry their young in a
handy pouch the cute but lazy koala and
the weirdest of all a beaked egg-laying
mammal called the duck billed platypus
in this video you will learn how these
weird and wonderful animals are formed
in the process of speciation speciation
is the formation of a new and distinct
species in the course of evolution many
millions of years ago the continents
that we know today were all joined
together in one supercontinent known as
Pangaea over several hundred million
years these continents slowly drifted
apart from each other when Australia
finally separated from the other
continents as animals and plants were
cut off from those on other land masses
this isolation is the first step in the
formation of new species it splits the
species into two different gene pools as
the animals and plant groups on the
Australian continent drifted away from
their relations they became isolated
from other populations of their species
because the sea acted as a barrier each
gene pool was now exposed to different
conditions like climate food and
competition this is the second step in
speciation some animals and plants that
were not well adapted to the new
conditions died whereas those that were
best adapted survived to the process of
natural selection the gene pool changed
and the organisms became more and more
different from those left behind this is
the third step in speciation eventually
these differences became so great that
isolated populations are unable to
interbreed and a new species is formed
this is the final step in speciation
there are many other examples the lemurs
and baobab trees in Madagascar that
became isolated from continental Africa
all the famous giant turtles and unique
flightless cormorants of the Galapagos
Islands that were isolated from South
America their ancestors arrived either
by flight swimming or on natural rafts
from the nearest mainland some of the
species presented here are highly
specialized their environment changes
due to human or natural influence they
may become extinct like the tasmanian
tiger a stripey doglike animal which
became extinct when humans entered its
habitat and started over hunting it
these are examples of speciation
happening because of physical barriers
members of the same species can also be
separated due to biological or
behavioral barriers birds of the same
species but living in slightly different
areas may over time develop different
mating rituals or different mating songs
and so the females are only attracted to
rituals of the male's from their area
similarly species living in different
areas may face different climates or
different food pressures and so their
mating seasons may end up being out of
sync with other members of their species
this happened two species of toad in
North America over time both of these
resulted in speciation and are known as
reproductive isolation so remember the
amazing variety of flora and fauna that
we have in our world is due to the
process of speciation the formation of a
new and distinct species in the course
of evolution