biological diversity vertebrates
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BIOLOGICAL DIVERSITYWhere do the rights of one specie start and the other ones end?
VERTEBRATES
ANIMAL DIVERSITY
WHAT IS A VERTEBRATE?
Animals with an internal skeleton made of bone are called vertebrates.
Vertebrates include fish, amphibians, reptiles, birds, mammals, primates, rodents and marsupials
VERTEBRATES TRAITS
The traits that makes them so special are the spinal cords, vertebrae, and notochords. It's all about having a series of nerves along your back (dorsal side). If you are an organism, you can't just have the nerves sitting there. You need to give those nerves support and protection. That need brings us to the backbones and a rod of cartilage called the notochord.
CLASSIFICATION
Subphylum
Vertebrata
Class Agnatha (jawless fishes)
Class Chondrichthyes (cartilagin
ous fishes)
Class Osteichthyes (bony
fishes)
Class Amphibia (amphibians)
Class Reptilia (reptiles)
Class Aves (birds)
Class Mammalia (mammals)
CLASS AGNATHA Agnatha is a group of vertebrates that lacks a jaw. The oldest fossil agnathans appeared in the Cambrian,
and two groups still survive today: the lampreys and the hagfish, comprising about 120 species in total.
Lampreys have a light sensitive pineal eye. Fertilization and development are both external. There
is no parental care in the Agnatha class. The Agnatha are ectothermic or cold blooded, with
a cartilaginous skeleton, and the heart contains 2 chambers.
Lampetra fluviatilis
Astraspis desiderata
CLASS CHONDRICHTHYE
Also known as cartilaginous fishes are jawed fish with paired fins, paired nares, scales, a heart with its chambers in series, and skeletons made of cartilage rather than bone.
The class is divided into two subclasses: Elasmobranchii (sharks, rays and skates) and Holocephali (chimaeras, sometimes called ghost sharks, which are sometimes separated into their own class).
Carcharodon carcharias
CLASS CHONDRICHTHYE The skeleton is cartilaginous.
Their tough skin is covered with dermal teeth.
All Chondrichthyes breathe through 5-7 gills, depending on the species.
Fertilization is internal. Development is usually live birth (ovoviviparous species) but can be through eggs (oviparous).
CLASS OSTEICHTHYES
Endocondral bones form the
skeleton
Even and odd fins
With jaws, ussually with
teeth
Breathing by gills and covered by the opercule
Swim bladder
Circulatory system with a
heart, with atrium and
ventricle without separation
Excretory system with
kidneys adapted to different
environments
Nervous system with small brain,
olfatory and optic lobes
CLASS AMPHIBIA
Resilient skeletal structure with
tetrapod appendix
Respiratory system with lungs and a pair of internal
nostrils
Double circulation with pulmonary
and systemic, heart with 3 chambers
The ear gets a timpanic
membrane
The cornea becomes the responsible
structure for light refraction, they
developed eyelids and lacrimal
glandules
MODERN AMPHIBIANS
Bone skeleton, with vertebraes, ribs, no exoskeleton.
Great diversity of shapes and forms.
2 pairs of extremities (tetrapods), with generally 4 fingers per anterior leg
Smooth and wet skin with many glandules.
Normally big mouth, with small teeth in the superior jaw, 2 nostrils that open in the back of the mouth.
Respiration by lungs and skin, independently or combined.
Trichamber heart circulation.
Ectothermics.
Separated genders with internal fecundation in salamanders and external in frogs and toads.
Oviparous, ovoviviparous and viviparous.
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