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CHAPTER TEN
ANIMALS WITH BACKBONES
* Information based on exerts
from “Concepts and Challenges
in Life Science Third Edition”
By: Raynald Laurent
WHAT ARE CHORDATES?
Notochord
Gill slits
Chordates are animals with backbone, animals closely
related to invertebrates and contain a notochord at some
point of their development. All chordates have a hollow
nerve cord and paired gill slits.
This diagram of a Lancelet shows the basic parts. Lancelets
are fishlike creatures that makes the sand of the ocean
floor their habitat. A lancelets'’ notochord never evolves into
a backbone.
Lancelet
WHAT ARE FISHES?
Fins
Scales
Eye
Gill cover
Fishes are the oldest group of vertebrates
appearing more than 500 million years
ago. Fishes are coldblooded animals.
They use their feathery organs called gills
to breathe. Their fins and tail fin are
there for them to swim.
Fins
http://www.fish4fun.com/waterway_artworks.htm
WHAT ARE AMPHIBIANS?
Amphibians are animals that a have a
habitat on land and water at separate
parts of their lives. It’s during their young
age they live in water and as they grow
and develop, and become a mature
adult they live on land. Amphibians are
also coldblooded with the exception of
toads. Amphibians have webbed feet
and they use their skin to exchange
oxygen and carbon dioxide.
http://www.scientific-art.com/portfolio%20zoology%20pages/reptamp.html
How Do Frogs Develop?
Frogs endure drastic changes in there
physical appearance and development
called metamorphosis. Amphibians go
through these changes as well.
These are the stages:
1. Frogs lay their eggs in water.
2. The eggs hatch in approximately 12
days and tadpoles are hatched.
Tadpoles resemble very small fish.
3. The tadpole grows and develops
over time into a young frog. The gills
are gone and lungs replace them. At
that point the young frog is ready
for life on land.
http://cnx.org/content/m19974/latest/
What are reptiles?
Reptiles are coldblooded animals with
the majority of them having two pairs of
legs with clawed feet. They were the first
true land animals. Retiles breathe
through their lungs. They have a threechambered or four-chambered heart.
There are 6500 different kinds of
reptiles.
http://beforeitsnews.com/story/385/375/Live_baby_dinosaur_discovered_in_New_Zealand.html
http://en.wikipedia.org/wiki/File:Florida_Box_Turtle_Digon3.jpg
http://etc.usf.edu/clipart/2100/2176/crocodile_1.htm
What are birds?
Birds, unlike amphibians, are warmblooded. The characteristics of birds are
two wings, two legs, lightweight bones,
birds have a beak without teeth and
birds lay hard-shelled eggs. The organ
system of birds are very developed.
Birds have a four-chambered heart. The
two upper chambers are the atria and
the two lower chambers are the
ventricles. There are different kinds of
birds, Birds of prey, Wading Birds,
Perching Birds, Nonperching and
Swimming Birds.
http://wmfclipart.com/images/Birds/CARDINAL.WMF.html
http://www.wmfclipart.com/images/Birds/PARROT.WMF.html
What are mammals?
Mammals are warm blooded animals. They are a group of vertebrates that include humans here are some of
the characteristics of mammals:
• Body Hair
• Four-chambered heart
• Highly developed brain and nervous system
• Female mammals nurse their young
Life Science Third Edition
How do animal embryos develop?
Water Animals
Land Animals
The female sex cell called the
egg, are laid in water by fish and
other animals that make that their
habitat. The male sex cell called
sperm is united with the egg in the
process of fertilization. Eggs are
fertilized outside of the female
body. The developing organism
called the embryo develops inside
the egg and consumes food stored
in the egg.
Eggs of mammals are fertilized
inside the body of the mother. The
embryo develops inside the
mother’s body. The embryo gets
its food from the mother, the
digested food and oxygen from
the mothers bloodstream, is
passed into the bloodstream of
the embryo.
http://ethics.davidson.edu/index.php/2010/02/the-moral-status-of-human-embryos/
http://www.pennmedicine.org/newsletters/preg_parenting/preg_printfriendly/week37.html