What Animals Are Included In The Class Reptilia
Review padlets (pass: bio)
Biology 2-1 review question padlet
Biology 1-1 review question padlet
- Reptiles were the outset animals adjusted to life entirely on land .
- Reptiles evolved from amphibians ~ 320 million years ago and displaced amphibians in many environments.
- Reptiles are ectotherms ("cold-blooded")
Major Evolutionary Advancement – Amniotic Egg
- Developed from internal fertilization and provides the embryo with atmospheric oxygen, nutrient, and water.
- Egg covered in a mineralized shell – reptiles take leathery eggs
- Removes nitrogenous wastes and protects the embryo from drying out.
- This marks the kickoff of the amniotes ( animals with amniotic eggs)
- Amniotes include : Class Reptilia, Form Aves, and Class Mammalia.
The amniotic egg is dissimilar because they have four extra membranes:
a. Amnion – thin membrane enclosing the fluid in which the embryo floats/prevents drying out.
b. Allantois – stores wastes produced by the embryo.
c. Yolk Sac – Surrounds the yolk (nutrients for embryo)
d. Chorion – Outermost membrane of the egg – protects embryo and allows gas substitution
General Anatomy
- Have claws to protect and help them obtain food
- ninety degree leg position Provides greater body back up compared to amphibians.
Integument: Tough, dry scaly skin that offers protection against desiccation (drying out) and physical injury.
- Pare can also have chromatophores for colouration.
- All reptiles shed their skin, still snakes shed the entirety of their skin in one session. This replaces old worn out skin and removes parasites.
Physiology
- Ectothermy – "Cold blooded"
- Reptiles are ectotherms, meaning they rely on environmental (or outside) heat sources
- Since they do non produce much internal sources of oestrus/regulation, ectotherms are able to use much less energy and have lower metabolic.
- The term "cold-blooded" is technically non correct since claret temperature changes with environmental temp.
- Merely, What most fish and amphibians?
- Fish and amphibians are all ectothermic likewise!
- Question: Reptiles and all previous vertebrate classes are ectothermic – tin can you make a prediction equally what major evolutionary advancement will occur in terms of thermoregulation?
Physiology – Senses
Jacobson'due south Organ
- The olfactory areas in the nose are not well developed in reptiles.
- Using their tongues, many reptiles, amphibians, and mammals can can notice chemicals (odour/gustation) in the air via the Jacobson's organ.
Heat -sensitive organs (or pits)
- In some snakes
- Detect the heat from casualty, and nerves transmit this info to the same area in the brain that receives optic nerve impulses (sees a "heat image" of prey – just like an infrared camera!)
Physiology – Digestive System
- Digestive tract is similar to amphibians, however is longer, with a larger J shaped s
Effigy six: Comparing vertebrate digestive systems (commencement five classes) tomach (similar to higher vertebrates such every bit mammals)
- It includes the rima oris and its salivary glands, the esophagus, the stomach, and the intestine and ends in a cloaca .
- One pair of salivary glands evolved to go venom glands in many reptiles. (yes, snake venom is modified saliva!)
Fun fact : Evolution of Snake Venom
- In snakes, venom has evolved to kill or subdue prey and due to its effectiveness, snakes diversified relatively apace.
- Interestingly, the venom organization has also subsequently atrophied, or has been completely lost in many species after its evolution.
- For example, many American Rat Snakes lost their venom following the evolution of constriction as a means of prey capture. (notwithstanding they still possess remnants of the organisation)
- BC has its own venomous rattlesnake – The Northern Pacific Rattlesnake (Crotalus oreganus oreganus)
Physiology – Reproduction
- Oviparous with internal fertilization (lays amniotic eggs)
- Most male reptiles have two sexual activity organs called hemipenes . They are housed internally in males only at the base of the tail, and are everted when needed.
- In many snakes, the hemipenes possesses spines or hooks, in order to ballast the male within the female.
- Unlike many other reptiles, alligators/crocodiles use a penis that is ever erect and "pops" out of their bodies to mate
Effigy 9: A graph plotting proportion of female turtles built-in vs. incubation temperature - In some reptiles, nest temperature determines sex of the hatchlings. This is called temperature-dependent sexual activity determination.For instance, In turtles, low temperatures during incubation produce males and high temperatures produce females.
Parthenogenesis – reproduction
- Parthenogenesis = reproduction from an ovum without fertilization
- The only vertebrates that show true parthenogenesis are the squamates, with most l cadger species and one ophidian beingness obligate parthenotes.
- These are unisexual species, all individuals being females that reproduce asexually without the intervention of whatsoever male person.
- Ex. Tropical Nighttime Lizards
Physiology – Circulatory system
-
Figure 10: Comparing vertebrate hearts Nigh reptiles accept a iii -chambered heart and double loop claret circulation (similar to amphibians)
- Withal, reptiles have an incomplete septum, or wall dividing the ventricle into two.
- More efficient than amphibians, but still not the most complex!
Crocodiles – a big difference!
Society Crocodilia (Alligators and crocodiles) have developed four chambered hearts and are closely related to birds – What heart structure would you await in Class Aves?
Physiology – Respiration
- Reptiles are more than active than amphibians, and so they need more oxygen.
- Reptiles cannot skin breathe; their dry scaly skin is "watertight" to avoid h2o loss.
- The lungs of reptiles contain a larger surface expanse
Groups of Reptiles
Order Testudines ("Turtles, tortoises, terrapins")
In North America:
Turtles…
- Are usually water -dwelling and have streamlined, disk -shaped shells and webbed feet or flippers to apace motion in h2o.
- They swim, but they also climb out onto banks, logs, or rocks to bask in the sun.
Tortoises…
- Are state -dwelling and tend to have dome -shaped shell to retract their head & limbs.
- They have thick sturdy legs and anxiety for moving on land and eats low-growing shrubs, grasses, and fifty-fifty cactus.
- Tortoises that live in hot, dry habitats use their potent forelimbs to dig burrows .
Terrapins…
- Spend their time both on land and in water, and alive along rivers, ponds, and lakes. Terrapins are ofttimes found in brackish , swampy areas.
Lodge Squamata ("Lizards and Snakes")
- Snakes and lizards have a kinetic skull , which means it is modified to take movable joints, specialized for eating large prey.
- In snakes, the two halves of the lower jaw (mandibles) are joined merely by muscles and skin, assuasive them to spread widely apart.
- Since a snake must go along animate during the deadening process of swallowing, its tracheal opening (glottis) is thrust forward between the two mandibles.
- Swallowing may accept several hours but saliva begins digestion during swallowing.
- Snakes take no external ears or tympanic membrane, simply are quite sensitive to vibrations carried in the ground – their jaw carries the vibrations into the ear to the cochlear os
Order Crocodilia ("Crocodiles and alligators"
- Crocodilians are large, aquatic reptiles; of the living reptiles, they are the most closely related to dinosaurs .
- Alive in tropical and subtropical regions around world and tin ordinarily exist distinguished based on head morphology:
Crocodiles – Long triangle -shaped heads; when oral fissure is airtight you tin meet the upper and lower teeth showing; teeth vary in size.
Alligators – Wide apartment heads with round noses; When oral fissure is closed only the upper teeth are showing; Teeth vary in size.
- All are aggressive carnivores
Guild Sphenodontia ("Tuataras")
- Tuataras are nocturnal, lizard-similar reptiles that live in burrows oftentimes shared with petrels. They usually hide in burrows during the day and feed on insects, worms, and other pocket-size animals at nighttime
- Only ii living species; both inhabit but a few pocket-size islands of New Zealand.
- They were once widespread throughout the ii main islands of New Zealand. Humans introduced not-native animals, including rats, cats, dogs, and goats, which prey upon tuataras and their eggs.
Figure 18: Tuatara
Source: https://blogs.ubc.ca/mrpletsch/2017/03/03/class-reptilia/
Posted by: scottovion1999.blogspot.com
0 Response to "What Animals Are Included In The Class Reptilia"
Post a Comment