A ppt on a part of the grade 10 CBSE biology chapter "Heredity and Evolution", talking about the "Evolution by stages". Hope this helps! :D

3. WHAT IF COMPLICATED ORGANS, SUCH AS THE
EYE , ARE SELECTED FOR THE ADVANTAGE THEY
PROVIDE, HOW CAN THEY BE GENERATED BY A
SINGLE DNA CHANGE ?
SURELY SUCH COMPLEX ORGANS WILL BE
CREATED BIT BY BIT OVER GENERATIONS?
BUT HOW CAN EACH INTERMEDIATE CHANGE BE
SELECTED FOR?
THERE ARE A NUMBER OF POSSIBLE
EXPLANATIONS

4. • EVEN AT AN INTERMEDIIATE STAGE , SUCH AS
RUDIMENTARY EYE , CAN BE USEFUL TO SOME EXTENT. THIS
MIGHT BE ENOUGH TO GIVE A FITNESS ADVANTAGE
•IN FACT , THE EYE LIKE THE WING - SEEMS TO BE A VERY
POPULAR ADAPTATION.
•INSECTS HAVE THEM, SO DOES AN OCTOPUS AND SO DO
THE VERTEBRATES.
•AND THE STRUCTURE OF THE EYE IN EACH OF THESE
ORGANISMS ARE DIFFERENT – ENOUGH FOR THEM TO HAVE
SEPARATE EVOLUTIONARY ORIGINS.

11. Some
Some
wanted to Some
farmers
select for have
wanted to
arrested selected
select for
flower for
very short
developme
distance
nt and have
swollen
between parts and
bred
leaves and come up
broccoli,
have bred
and have with
the cabbage
made kohlrabi
they eat
cauliflower

18. The beaver has many interesting adaptations.
 They have long, sharp incisors that never stop
growing, so as they wear them down chewing
trees, they keep growing back.
They can also close their nostrils and
.
throat while carrying sticks around in
the water. This keeps them from
drowning while they carry sticks to and
fro underwater.

19. They have a thin membrane over their eyes
that allows them to see underwater while
protecting their eyes like swim goggles!
They also have a thick coat so they can
swim under the ice in the winter and oil
glands to keep their fur well oiled. The
beaver is well adapted to its habitat