Transcript Marine Reptiles and Birds - Science with Ms. Reathaford!

Characteristics:
 Birds have some significant advantages over
reptiles, including their ability to fly, which is
made easier by their light, hollow bones
 Birds are homeotherms, or warm-blooded, and
are also endotherms which allows them to
retain some heat to raise their body
temperature
 The bodies of seabirds are covered with
waterproof feathers to help them conserve body
heat. (Waterproofing is provided by oil from a
gland above the base of the tail)
 Their eggs have hard shells that are more
resistant to water loss than those of reptiles
Birds that spend a significant
part of their lives at sea and
feed on marine organisms are
seabirds.
Seabirds descended from
several different groups of
land birds. Because of this,
they differ widely in their
flying skills, feeding
mechanisms, and ability to
live away from land.
Though seabirds are only about
3% of the estimated 9700
species of birds, seabirds are
distributed from pole to pole
and their impact on marine
life is significant.
 Seabirds
have amazing appetites and need a lot
of food to supply the energy required to
maintain their body temperature. Most seabirds
are predators of fish, squid, and bottom
invertebrates but some feed on plankton.
 Seabirds
nest on land, breed in large colonies,
mate as life-long pairs, and take care of their
young.
 True
seabirds have webbed feet for swimming.
Tubenoses comprise a large
group of seabirds with
distinctive tube-like nostrils
and heavy beaks that are
usually curved at the tip.
Tubenoses spend months and
even years on the open sea,
they have salt glands that
empty into the nostrils to get
rid of excess salts.
They are skillful fliers, which
most take advantage of by
catching fish at the sea
surface. Others scavenge on
The Albatross has a wingspan of up to
dead birds or whales. Some
11ft, the longest of any bird alive!
have huge wings that hardly
ever seem to flap.
Male and female tubenoses remain
faithful to each other and perform
elaborate courtship and greeting
behaviors.
Most nest on cliffs that are
inaccessible to predators or on
remote islands. Incubation and
care of a single chick takes 8
months, at minimum.
Tubenoses make some of the most
spectacular migrations. Many
breed on islands around
Antarctica, then migrate across
the open ocean to summer
feeding grounds near the Arctic
Main Characteristics:
 Webbing between all four toes
 Relatively large fish eaters of wide
distribution
 Nest in large colonies along the coast
Pelicans
 Unique pouch below their large
beaks
 Some feed by plunging into the
water and catching fish in the pouch
 Brown Pelicans were once common
along the coast of the United States
but was decimated by pesticide
pollution. Due to restrictions on the
use of pesticides, it is making a
comeback…
Cormorants
Characteristics:
 Black, long-necked
 Range in size from
approximately 18in to
40in
 Coastal birds, rather
than open-water birds
 Dive and pursue their
prey
 Low flights over water,
only their necks are
above the surface
Frigate Birds
Characteristics:
 Sometimes called Pirate
Birds
 Narrow wings and long,
forked tail
 Males have a red pouch
that inflates during
mating season to attract a
female
 Soar majestically along
coast forcing other
seabirds to regurgitate
fish in midair or catching
fish from surface
 Seldom enter the water as
their wings are not very
waterproof
Cormorant
Frigate Bird
Characteristics:
 Gulls and their kin make up the largest variety
of seabirds.
 Common and widespread
 Gulls are predators and scavengers that will eat
just about anything
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Very successful in the company of humans,
congregating near them on beaches while they are
eating.
Some gulls steal food from other birds
Nest near the rookeries of penguins and other
seabirds and eat their eggs and young
Terns
Characteristics:
 Graceful flyers
 Hover over prey prior to
plunging after it
 Slender, specialized
beaks to catch small
fish that they swallow
whole
 “Amazing wanderers”
for breeding and
feeding
Puffins
Characteristics:
 Heavy beaks, similar to
parrots
 Cold-water diving
seabird
Razorbill
Characteristics:
 Black and white, reminiscent
of penguins
 Use wings to swim
underwater
 Found in Northern
Hemisphere (penguins are
not)
Royal Terns
Puffin
Royal Terns
Gulls
Razorbill
Characteristics:
 Do not have webbed
feet so do not swim
 Many wade in inland
waters, some live in
sea
 Common in estuaries
and coastal marshes
Sandpiper at coastline
Characteristics:
 Flightless, wings are modified into stubby flippers to help them
“fly” underwater
 Bones are more dense than other birds to reduce buoyancy –
needed for diving
 Spectacular swimmers
 Can jump out of water and cover long distances between
swimming and jumping
 Clumsy and awkward on land, eyes are best adapted for
underwater vision
 Adapted for cold temperatures due to layer of fat under the
skin
 Waterproof feathers that trap air (warmed by body heat) and
protects against the cold like a down coat
 Live primarily in Antarctica and other cold regions of the
southern hemisphere (all but 1 of 18 species)
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The exception is the Galapagos Penguin, living right on the equator,
but this penguin is confined to regions bathed by cold currents
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Larger penguins (Emperor)
hunt for fish and squid /
smaller penguins (Adelie)
feed mostly on krill
Strong beaks, like other
seabirds, to help with
feeding
Some migrate seasonally
for feeding / nesting
purposes between the sea
(feeding) and cold icy
areas (nesting)
Penguins lay their eggs at
the coldest time of year,
to time out hatching
during the productive
Antarctic summer where
food is plentiful
The Emperor Penguin, as seen in
“March of the Penguins”, mates in a
manner that is fascinating to
humans. Both male and female
sacrifice much of themselves to
hatch a single chick.
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The male incubates the egg during the
dark winter while the female leaves to
feed. The male hold this position,
incubating the egg, for approximately 64
days while huddling with other males to
keep warm.
Females return to the nesting sight and
regurgitates food she has eaten for her
chick.
Once the female returns and begins
feeding her chick, the male prepares to
leave by singing with his chick (so when
he returns from feeding he can find the
chick).
Upon the males return, both take turns
feeding the chick until it is old enough
and strong enough to feed itself at sea
(5.5 months).
Vertebrates originated in the ocean and have
thrived there ever since. Roughly 350 million
years ago however, vertebrates invaded the
land.
Descendants from bony fishes, land vertebrates
had to adapt to harsher conditions ashore. They
lost structural support of the ocean and had to
develop ways of moving around.
They evolved with two pairs of limbs as an
adaptation for walking between pools of water
and because of this, they are called
“tetrapods”. Tetrapods means “four-footed”
Living on land also meant having to breathe
air, so tetrapods had to develop lungs.
They also had to develop a means to keep
from drying out.
The first land tetrapods (amphibians) never
solved this problem and became a
stepping stone for further evolution into
reptiles.
Having adapted to the land, various groups of
reptiles reinvaded the ocean.
Unfortunately, many of the marine animals
we will discuss throughout the remainder
of the semester are in danger of
disappearing forever because of our own
greed. Some have already become extinct.
Plesiosaur – Triassic Period
There are around 7,000 living species of reptiles,
first appearing more than 300 million years ago.
Like most fishes, reptiles are poikilotherms
(organisms that have a body temperature that
varies with the environment).
Reptiles have adapted to life on land through
development of dry skin with scales to prevent
water loss, as well as leathery shelled eggs to
allow them to lay their eggs on land without
fear of the eggs drying out.
Today, only a few species of marine reptiles roam
the seas. Some are rare and endangered, while
others are common and widely distributed.
Types:
1.
2.
3.
4.
Sea Snakes
Marine Iguana
Saltwater Crocodile
Sea Turtles
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Approximately 55 species of sea snakes are found in the
tropical Indian and Pacific oceans.
Bodies are laterally flattened with a paddle-shaped tail
for swimming
Most are 3-4 feet in length and practically all species live
a totally marine existence
Mating occurs in the ocean, where most give birth to live
young (ovoviviparous) although there are a few species
that come onto land to lay eggs
Sea snakes are carnivores, feeding on bottom fish and
fish eggs
Most common venomous snakes, bites are fatal to
humans, but they are rarely aggressive and have small
mouths so they are unable to get a good bite
Most casualties come from swimmers stepping on them
and fishermen removing them from nets
Sea snakes are rare because they are hunted for their
skin
Sinous Sea Snake
Found off of the
Pacific coast of South
America in the
Galapagos Islands
 Spends most of its
time basking in large
groups on rocks along
the coast
 Thought to “bask” in
the sun to warm itself
up after swimming in
the cold water
 Eats seaweed
 Can dive as deep as 33
feet to graze
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of the Galapagos Islands
Red Marine Iguana
 Inhabits
mangrove swamps and estuaries in the
Eastern Indian Ocean, Australia and some of the
western Pacific Islands
 Live mostly on the coast but are known to
venture into the open sea
 Rarely over 20 feet long
 Most aggressive of all marine animals – WILL
attack (AND EAT) people
 Within the regions they are found, they are
feared more than sharks
Saltwater Crocodile
Characteristics:
 Belong to an ancient group of reptiles
 Bodies are enclosed by an armor-like shell
(carapace)
 Shell is fused to backbone
 Cannot retract their head into their shell like
land turtles and tortoises
 Legs are modified into flippers for swimming
 Only 9 species remaining, 6 in the United States
(All 6 species are protected through the
Endangered Species Act of 1973).
 Live primarily in warm waters
Green turtles were
once found in coastal
waters throughout the
tropics
 Shell may grow up to
40in in length
 Feed mostly on
seagrasses and
seaweeds
 Lack teeth, but have
strong biting jaws
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Green Turtles
Smaller than the green
turtle
 Shell is reddish brown
with yellow streaks
 Uses its beak-like
mouth to feed on
encrusting animals and
seaweeds
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Hawksbill Turtles
The largest sea turtle,
reaching a length of up to 7ft
and weighing at least 1200
pounds
 Series of small bones buried
in dark skin, instead of a
solid shell
 Open-water species, widest
ranging of all marine reptiles
 Rarely seen unless nesting on
beaches
 Deep divers, once tracked at
2100 feet!
 Feed primarily on jellyfish
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Facts:
 All sea turtles must return to
land to reproduce and they
do so every 2 to 4 years
 Migrate long distances to lay
eggs on remote sandy
beaches and have been doing
so for millions of years,
returning to the same
nesting grounds generation
after generation
 Turtles regularly cross 1300+
miles of open water to their
feeding grounds, which is a
journey that takes a little
more than 2 months
 Scientists are not positive,
but believe they find their
way by sensing the Earth’s
magnetic field
Loggerhead turtles nesting on the
North Pacific coast
Copulating pairs of sea turtles are often seen
offshore, but only females venture ashore – usually
at night.
 Females congregate on beaches and each makes a
hole in the sand using both pairs of flippers
 They lay between 100-160 leathery eggs in their
nest and then covers them with sand before
returning to the sea
 During the breeding season females may make
several trips ashore, where she lays eggs each time
 After about 60 days of incubation in the sand, the
eggs hatch. Babies must then dig themselves out of
the sand and crawl back to the water
 Hatchlings are easy prey for land crabs and birds
and are also lost in the water by various fishes and
seabirds
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make their way back to sea
Baby Loggerheads