class reptilia class amphibia. chordata latin term for chord
TRANSCRIPT
Chordata- Urochordata, Cephlachordata, Agnatha, Chondrichhyes,Osteichhyes, Aves, Mammalia
The best classes: Reptilia and Amphibia
Amphibia– Latin meaning “two lives” [water and land based]
Ex. Salamanders, frogs, toads
http://webpages.charter.net/teefile/biognomen/photo/Amphibia.jpeg
http://news.siu.edu/news/May05/images/salamander.jpg
http://www.lemmykoopa.com/lk19/2_5.jpg
http://library.thinkquest.org/TQ0312042/Images/American%20Toad.jpg
• Amphibians were the first vertebrates on land
• Early amphibians- lobe-finned fishes with lings, freshwater [b/c of drought] paired appendages to walk on land
Types of Amphibians
Urodeles- walk with lateral bending of the body i.e. salamanders
Anurans- use legs for hopping i.e. toads/frogs
Apodans- burrowing, legless, nearly blind, wormlike i.e. snake-type animals
Amphibia
Gas exchange- integuments (outer covering) allow gas exchange through skin; Adults generally respire using lungs and through moist skin
Skeletal- bony skeleton
Reproduction- External fertilization requires aquatic environment
General Characteristics
Of Phylum Chordata• notochord • dorsal hollow nerve chord • pharynx slits • muscular postanal tail
Body cavity-- coelom present; heart inside
Symmetry-- bilateral
Nervous– Brain reguates digestion and circulation; muscular coordination
Circulatory system– 3-chamber <3; mixed blood in single ventricle; pulmonary veins; only organ in coelom
Sensory– smell: two holes and olfactory lobes; crude eye: cannot change focus, eyelid; exposed ear
Digestion- mouth, weak teeth, sticky tongue to capture prey, esophagus, stomach, intestines, liver, pancreas, gall bladder
Excretory– liquid pass kidney to bladder; liquid and solid exit through cloaca. Urea gets rid of nitrogenous waste
Musco-skeletal– walking legs w/ <5 toes, flat skull, backbone, “shoulders,” leg bones
• Class Reptilia: (Latin repere, "to creep").
• The 3 largest and most diverse orders:– Crocodilia (alligators & crocodiles): 23
species – Squamata (lizards & snakes): approximately
7,600 species – Chelonia (turtles): approximately 300 species
Major Groupings
Tuatarahttp://
members.tripod.com/NZPhoto/animal/
tuatara.htm
Crocodilehttp://www-
biol.paisley.ac.uk/courses/Tatner/biomedia/subunits/
order57.htm
Zebra-tailed lizardhttp://
en.wikipedia.org/wiki/Lizard
Green Sea Turtlehttp://www.nmfs.noaa.gov/pr/
species/turtles/green.html
San Diego Alligator Lizard
http://www.yosemite.ca.us/library/reptiles/images/thumbnail/lizards_22.jpg
Gecko-Reptile; this is some kind of local reptile…
or something
Coleonyx variegatus abbotti
http://www.werc.usgs.gov/fieldguide/images/covajuv.jpg
Anatomy• Extraembryonic membranes:
– from embryonic tissue layers– Consist of:
• amnion (for protection), • yolk sac (expands over yolk, where nutrients are
stored)• allantois (disposal sac & functions as respiratory
organ)• chorion (functions as respiratory organ)
– involved in gas exchange, waste storage, and nutrient transfer from egg to embryo
Amniotes!
amniote = a reptile whose eggs contain specialized membranes that allow them to develop out of water
– The first amniote reptile evolved from an amphibian about 300 million years ago.
salamanders = amphibians; aren't amniotes; eggs lack the shell.
reptiles, birds, and mammals are amniotes
• Amniotic egg:– Enclosed in a waterproof shell and permitted
vertebrates to complete their life cycle– The shell retains water and can therefore be
laid in a dry place
Physiology• Body Cavity: coelom present
• Body Symmetry: bilateral
• Circulatory System:
– Ectotherms – absorb external heat rather than generating their own (“cold blooded”)
– Exchange of oxygenated and deoxygenated blood between the ventricles in all reptiles but the crocodile
• Digestive System: All reptiles except snakes have a cecum, at the beginning of the large intestine; gall bladder present; caudal abdomen stores fat.
• Gas Exchange: Reptiles have well-developed lungs enclosed within a protective rib cage.
• Locomotion/Musculature: Most reptiles have legs with usually five clawed fingers or toes
• Excretory System: – Crocodilians, snakes and some lizards
do not have a urinary bladder– those with a bladder, have it connected
to the cloaca by a short urethra.
• Skeletal Type:– Vestigial pelvic and limb bones in
primitive snakes are evidence that snakes evolved from reptiles with legs
– Scales contain the protein keratin which waterproof the skin
• Sensory Structure/ Features:
– Snakes have acute chemical sensors & are sensitive to ground vibrations
– Heat-detecting organs between the eyes and nostrics of pit vipers & rattlesnakes are sensitive to temperature changes
• Nervous System: well developed especially within the brain and with regard to optic nerves; visual sensory system
• Reproduction: Some species lay shelled amniotic eggs and fertilization is internal
Reptiles vs. Amphibians
• Amphibians have shell-less eggs, while reptiles have amniotic eggs that have a shell that retains water and can be laid in a dry place
• Reptiles have scales containing the protein keratin, which waterproof the skin to prevent dehydration in dry air
Quiz
Why do you think reptiles need fewer calories than mammals?
a. Ectothermic
b. Waterproof scales
c. Amniotic egg
d. More effecient respiratory system
A
What is true of amphibians?
a. Amphibian's blood is blue-colored
b. They have a 3-chambered heart
c. They only respirate through skin
d. Amphibians are green… always
A
What is not distinct about reptiles?a. reptiles have amniotic eggs that have a shell that retains water and can be laid in a dry placeb. Reptiles have scales containing the protein keratinc. They have waterproof skin to prevent dehydration in dry aird. They like cheetosE. All of the above are true about reptiles