Emergence of the animal kingdom

Emergence of the Animal
Emergence of the Animal
Kingdom
Kingdom
Or “Rise of the Chordates”
Phylum Chordata
Leading to
Subphylum Vertebrata 

Chordates include the following:
1.
1.
Fish
Fish
2.
2.
Reptiles
Reptiles
3.
3.
Amphibians
Amphibians
4.
4.
Birds
Birds
5.
5.
Mammals
Mammals

Chordates
Chordates
–
4 characteristics
1. notochord - support
2. post-anal tail
3. pharyngeal gill slits
4. dorsal hollow nerve cord

Chordate Characteristics

Gills in Humans! – check it out

Tunicates are Chordates!
Sea Squirts
•
sponge like - filter feeder
•
larva free swimming,
bilateral with all Chordate
traits

•
Lancets (a primitive fish like organism) closely
resembles the idealized chordate.
–
The notochord, dorsal nerve cord, numerous gill
slits, and post-anal tail all persist in the adult
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

“Ontogency Recapituates
Evolution”
Evolution Playing out in Fetus…
(all these Chordates (birds,
mammals, reptiles, fish, have
strikingly similar
Embryonic Development)


Chp 33 – Rise of the Mammals
•
Definition of a Mammal:
1. Homoeothermic – meaning that mammals
produce their own body heat
2. Mammary tissue - for the production of Milk
3. Hair Follicles - for the production of Hair
4. Generally, internal fertilization and harboring
of young, however, this is only a generality
because not all young are “cooked” to term
internally.

Monotremes – an Order of Class
Mammalia
Monotremes
eg. The Platypus, which has a BILL, lays EGGS, but still has
mammary glands and produces MILK for young. This
suggests a relationship between REPTILES, BIRDS and
mammals. Imagine that?

Marsupials
– eg. The Kangaroo, which is a non-placental mammal.
Here, the development of the young is very
complex, and a baby kangaroo is born very
“uncooked”, and must crawl into the mother’s
pouch and latch onto a nipple to receive milk to
continue development. You might say, baby
Kangaroos or “Joey’s” get a womb with a view 

Kangaroo Birth
17 Weeks

Placental Mammals
– eg. You – well if you’re female, anyway. Internal
Fertilization development of young to a highly
Advanced stage.

The Placenta is Key

In Mammals, all the Major Body
Systems are online and advanced

Skeletal System

Muscular System

Advanced Circulatory System

Respiratory System

Nervous System is online and
advanced!

Excretory System – ooo look,
Kidneys!

Endocrine System – Controls
you Hormones

Lots of Mammals in the Simpsons


Lastly, we can Learn Important
Lessons from Mammals like Homer