Lab 8 Handout

Clawsandnailsevolved withthefullmovetoland

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: pod
ancestor
and
become
increasingly
modified,
in
conjunction
with
the
circulatory
 system,
to
provide
better
respiration
in
air.

 3 Claws
or
Nails:
having
hard
parts
provides
protection
of
the
outer
ends
(finger
and
 toes)
of
limbs
and
assists
in
ripping
and
tearing
of
food
or
prey
(absent
in
amphibians).

 4 Internal
Fertilization:
In
order
to
move
reproduction
away
from
the
water,
 fertilization
must
take
place
internally.

 5 Amniotic
egg:
This
type
of
egg,
with
a
shell
and
several
membranes,
provides
 protection
from
drying
out,
while
still
allowing
gas
exchange.
It
first
appears
in
the
reptiles.

 6 Kidneys:
Another
trait
that
first
appears
in
the
reptiles,
the
kidneys
are
efficient,
 specialized
organs
that
excrete
waste
while
recycling
water
back
into
the
body.

 7 Air‐breathing
young:
Reptiles,
birds
and
mammals
(and
some
amphibians)
produce
 young
that
are
not
dependent
on
standing
water.

 
 
 Amphibians:
The
first
tetrapod
vertebrates
 The
evolution
of
tetrapody
(having
four
limbs
or
legs)
allowed
the
invasion
of
land.
 Amphibians
are
the
earliest
tetrapods
found
in
the
fossil
record.
At
first
amphibians
were
 often
quite
large.
Modern
amphibians
are
all
comparatively
small.

 
 There
are
more
than
6000
species
of
amphibians
living
on
the
planet
today.
This
group
 consists
of
frogs,
toads,
salamanders,
and
the
lesser‐known
caecilians,
which
are
legless
 amphibians.
Although
this
class
has
highly
diverse
body
shapes,
most
living
amphibian
 adults
are
carnivorous.
The
types
of
prey
that
they
eat
are
limited
by
the
size
and
shape
of
 their
heads.
Amphibians
with
larger
heads
are
capable
of
eating
larger
food.
Much
of
the
 diversity
we
see
in
amphibians
results
from
alterations
in
the
pattern
of
locomotion.
 Salamanders
retain
the
ancestral
type
of
movements,
while
frogs
and
caecilians
both
have
 derived
types
of
movement.
While
amphibians
show
many
distinct
characteristics,
they
are
 united
by
the
presence
of
mucous
glands
in
the
skin
that
keep
the
skin
moist
and
allow
for
 cutaneous
gas
exchange.
This
trait
allows
amphibians
to
move
into
terrestrial
environments,
 but
also
keeps
them
mostly
restricted
to
moist
areas,
since
water
can
also
be
lost
through
 the
skin.

 Most
species
of
amphibians
live
in
water
at
some
time
in
their
lives,
and
amphibian
eggs
 need
water
to
develop.
The
e...
View Full Document

Ask a homework question - tutors are online