Vertebrate Zoology Second Exam Guide for March 2021
Chapter 10—Origin and Radiation of Tetrapods
In which geological period do the tetrapods originate? Figure 10-1 on page 162. Where geographically? Greenland.
The first tetrapods appear in the Devonian. Cladogram is on page 163. The first tetrapods were Acanthostega and Icthyostega The Devonian tetrapods such as Acanthostega and Icthyostega appear to be residents of the aquatic land/water interface. Body size was large (3-6 feet in length). They had 8 toes which is the primitive condition. Why come to land???? Food, Predation, Competition.
The most successful group of Paleozoic tetrapods were the Temnospondlyls which appeared in the Carboniferous and disappeared in the Cretaceous. They come in many body forms and sizes.
The Temnospondlys gave rise to the Lissamphibians in the Triassic. The lissamphibians have survived to the present.
The temnospondyls lepospondyls, anthracosaurs and the osteolepiform fishes appear to be paraphyletic. There are not enough specimens to determine clear monophyletic relationships.
What does the amniotic egg have that does not appear in the anamniotic egg? Structures? Can you identify the structures in an amniotic egg?
What is the evolutionary advantage of being amniotic?
There is a fascinating figure 10.14-13 on page 176. It shows the ancestral anapsid leading to synapsids and sauropods. Why is skull fenestration important?
Chapter 11—Salamanders, Anurans and Caecilians
Class Amphibia, Subclass Lissamphibia (smooth skins), Order Gymnophonia=Apoda (Caecilians), Order Urodela-=Caudata—Salamanders and Order Anura for Frogs.
What are the primary characteristics of the lissamphibia?
Shared derived characters. Table 11.1 Page 182—6 of them 1. Structure of the skin, 2 a papilla amphibiorum, 3 operculum-columella complex, 4 green rods, 5 pedicellate teeth, 6 structure of the levator bulbi muscle.
What are the three major groups of lissamphibia? Anura, Urodeles, Caecilians
Which family of salamanders is the most diverse? Plethodontidae, Salamandridae Hynobiidae. Least Diverse? Cryptobranchidae, Sirenidae, Amphiumidae, Proteidae/
What are unique characteristics of these families? No lungs in the Plethodontidae. Some totally terrestrial, some both terrestrial and aquatic. anatomy, physiology, toxicity……
What are the major types of reproduction in amphibians? Internal vs external fertilization. All salamanders and caecilians are internal fertilizers. These animals produce sperm packets known as spermatophores. Anuran are external fertilizers with the exception of the tailed frog Ascaphus. Who does what and why? What are the consequences (advantages vs disadvantages) of internal fertilization and external fertilization?
Locomotion in salamanders is the primitive style with 4 limbs and crawling. Anurans have a fused spine creating a pelvis with a urostyle. This urostyle is very strong anatomically and permits hopping, jumping, crawling and makes the anurans so successful with over 6700 species of frogs and toads. The vertebral column is short with only 5-9 presacral vertebrae and the zygapophyses are strong. What are zygapophyses?
The most diverse groups of anurans are: True Toads=Bufonidae, True Frogs=Ranidae, Tree Frogs=Hylidae, Microhylidae are diverse families. The tailed frogs Ascaphidae/Leiopelmidae have 3 species total.
How do anurans reduce water loss? Get out of the dry area by burrowing or never leave the water.
How do anuran amphibians breathe? Lungs and skin in anurans.
How do anurans make sound? Males only and mating calls. What kinds make sounds? Why do they make sounds? Reproduction. Do urodeles make sounds? No. How about caecilians? No.
Parthenogenesis, gynogenesis, hybridogenesis—What is the difference? In which groups do these processes occur? Ambystoma (mole salamanders)
What kinds of secondary sexual characteristics occur in amphibians? Typically cornified epithelium for mating (calloused thumbs) and hardened tubercles(spade foots) for digging in the soil. Salamander and newt males have enlarged tails for swimming speed to capture females.
Metamorphosis in amphibians is by what chemical? Iodine is required for the hormone thyroxine. What happens if a larva becomes sexually mature? Paedogenesis or Neoteny occurs in the Axoltyl salamanders in Mexixo.
What types of toxins occur in amphibians? Poison Arrow frogs and other species have neurotoxins on the skin or in glands. Why? Toads have large paratoid glands on the head that produce emetic and toxic responses when a predator tries to eat the toad.
What is aposematic coloration? Bright warning color in poison area frogs.
Several species of salamanders and frogs have direct development in which the tadpole stage occurs 100% in the developing egg. Others lay eggs in the water and have aquatic tadpoles. Caecilians have both direct development and aquatic phases.
What are the reasons for declining amphibians? Climate change, disease, ultraviolet light, habitat destruction, acid precipitation causing low pH in ponds.
Living amphibians occur on all continents except Antartica.
Chapter 12—Living on Land
In adapting to land there were greater forces operating on the vertebral column. In the amniotes evolution of body support included the development of concentric layers around blood vessels known as Haversian Systems.
Axial skeletons in land vertebrates have support structures called zygopophyses. Aquatic tetrapods that reinvaded the ocean have lost these support structures.
How does the vertebral column differ in fishes and amniotes?
Vertebrae in amniotes are specialized into cervical, thoracic, lumbar,sacral and caudal vertebrae.
Fish turn the body when looking around whereas Fishapods like Titktaalik had a “neck”. (see Figure 12.4 for picture)
What is the tetrapod limb derived from?
Figure 12.3 (page 214) is a comparative drawing of the morphological and physiological characteristics of lobe finned fish, a non amniotic tetrapod and a early amniotic tetrapod. You may see an image of these critters and have to identify the structure. Just saying.
Are five toes primitive or advanced? How do you know?
How do lobe-finned fishes and tetrapods vary in terms of blood circulation? Figures 12.10 and 12.11 on Page 222-223.
What are the major reasons for fishes to colonize land?
What is allometry? Why do comparative anatomists talk about “scale” in vertebrate structure?
What major branchiomeric muscles are retained in tetrapods from fishes?
Which group of primitive amphibians gave rise to the lissamphibia? Temnospondyls.
What is the difference between an amniotic and a non amniotic egg?
Vertebrates have developed the senses. Vision-Vertebrates have eyes with lenses. Most have a fixed lens but many fishes have a lens that is movable, Smell is enhanced in mammals by the turbinates in the nose. Also Flehmen behavior in ungulates allows for enhanced sensitivity. Echolocation occurs in bats of the group microchiroptera. Ultrasonic sounds emitted by the bat are in the FM range and permit the bat to image the prey. Porpoises emit high energy clicks that are focused by the melon and the returning sound is received by the lower jaw. How do each of these sensory mechanisms work?
Ectothermy is the dominant mode of for all of the vertebrates except birds and mammals who are endothermic. Think poikilothermy=ectothermy and endothermy=homeothermy. Ectothermy is much more efficient in energy use but it limits the time and temperature in northern climates.
Chapter 13: Geography and Ecology of the Mesozoic (triassic, jurassic, cretaceous)
Early Mesozoic the single continent Pangaea (Figure 13.1 page 234) but by the beginning of the Cretaceous the continental breakup was in full swing with the Atlantic ocean coming into being. By the middle of the Mesozoic the land masses were separated enough to show distinct floras and faunas.
The Angiosperms (flowering seed plants) appeared in the Cretaceous.
Jurassic dinosaurs reached large size and evolved into specialized large herbivores in the Cretaceous.
Mammals, birds and modern amphibians and reptiles also appeared in the Mesozoic.
All the dinosaurs were gone by the end of the Cretaceous in what is known at the K/T boundary. However many groups did make it through this extinction event. This includes the snakes, lizards, crocs, birds and mammals. The extinction event may have been caused by a giant comet, asteroid or just plain volcanism. Spock came to earth from the planet Vulcan and killed off the dinos so people could evolve, then he came back later to work on the Enterprise with Capt. Kirk!!
Chapter 14—Synapsids and Sauropsids
Synapsid and Sauropods had diversified by the mid Carboniferous and began evolving derived charcters of terrestrial life. Both lineages developed systems independently such as respiratory sysstesm, excretory systems, endothermy in birds and mammals, feathers and fur and parental care.
What is the gastralia and what does it do? The ventral ribs and pelvic movements in sauropods was sufficient for lung ventilation. Which living organisms have one? Reptiles and birds. What kind of fossil tetrapods have gastralia? Dinosaurs and other reptiles.
There are two types of lungs in amniotes. Alveolar and Faveolar. Why the difference and how do they work? Which lung is more efficient? Faveolar
Who is a living synapsid? (mammals) Who is a living sauropod? (turtles, lepidosaurs, crocs, and birds) Why the difference?
Heart: Ancestral amniotic heart lacked a ventricle septum. Turtles, Lizards and Snakes have a 3 chambered heart. Crocs have a 4 chambered (divided ventricle) heart along with birds and mammals.
What are the waste products produced by the body in amphibians, reptiles, birds and mammals? Table 14.1 and 14.3.
Why are there different types of waste products? Ammonia, Urea, Uric Acid.s Which are most toxic. What is metabolic water?
How does the structure of the kidney vary between different groups? Only mammals have a Loop of Henle to produce a urine that is more concentrated than the blood plasma U/P ratio greater than 1. Table 14.2 page 258
How do these animals get rid of excess salt? Glands in the skin, nose, tears and anal.
Table 14.4 page 262
Which groups of organisms produce a urine that is more concentrated than the blood plasma. Table 14.2 page 258
Which groups of vertebrates have salt glands to eliminate excess salt?
Figure 14.15 shows that larger body mass is strongly correlate with brain mass. Mammals are big brained compared to reptiles and birds.
Chapter 15: Ectothermy: A low cost approach to life
What are the waste products produced by the body in amphibians, reptiles, birds and mammals? Ammonia, Urea and Uric Acid.
What is the advantage of using ammonia. The disadvantage? You can do this for all the vertebrate groups.
How does the structure of the kidney vary between different vertebrate groups? Think Loop Henle in Mammals. Reptiles cannot produce a urine that is more concentrated than the blood plasma. Reptiles remove excess salt through nasal secretions. Text information on kidney function is in Chapter 14 and discussed in Chapter 15 in relation to living species.
How do amphibians survive being frozen? The formation of extracellular cellular fluids (glycerol)outside the cell results in freezing without cellular damage. If the inside of the cell freezes the animal does not survive. Amphibians dehydrate in the fall of the year as cold weather is approaching. Page 276. Does this happen in any other Reptile (yes in turtle eggs), Bird or Mammal (no)?
Why is ectothermy so successful? Think energy efficiency, metabolic rate, activity.
What is the downside of being ectothermic? Energy budgets for lizards and turtles in desert environments indicate that these species utilize behavior and physiology to accommodate seasonal environmental changes.
Chapter 16—Turtles
The first turtles appeared in the Triassic Period of the Mesozoic around 220 million years ago. The closest relatives may be the parareptiles.
Where did turtles come from? Look at the cladogram. Figure 10.1page 162
Name the bottom (plastron) and top (carapace) shell of the turtle?
How many total species of turtles are living? 346 or more.
What divides the turtles into two major groups? Necks-pleurodira and cryptodira. List the characteristics of each group. Which group is the most successful (cryptodira) These animals are known as anapsids. Why?
What is the turtles shell made of?
Gas exchange occurs in what portions of the anatomy of a turtle? What is the significance of gas exchange other than the lungs?
Are there any turtles that can maintain body temperature above the environment without using the sun? YES—Large sea turtles (Leatherback) maintains warm body temperature in cold water by heat from swimming muscles.
What kind of sexual dimorphism occurs in turtles?
Explain sex determination in turtles. TSD and GSD/
How does turtle conservation relate to sex determination?
Which turtle swims to Ascension Island for egg laying? How does this turtle find the island?
What types of diseases do turtles have?
Chapter 17–The Lepidosaurs
What are the characteristics of living reptiles?
What is unusual about the tuatara? Third eye! Where does it live? New Zealand. This organism occupies the Order Rhynchocephalia by itself. The fossil record is rich and reaches back into the Triassic.
Lizards and Snakes are known as squamates or scaled reptiles. This is the Order for snakes and lizards.
Lizard Dentition occurs as acrodont and pleurodont? How are these defined? The dentition type separates two major families. Iguanid lizards (new world) are pleurodont and Agamid lizards (old world) are acrodont. These organisms are similar in morphology and behavior.
How can you tell the difference between a lizard and a snake? Lizards have eyelids and auditory openings and snakes do not.
What separates primitive and advanced snakes? Primitive snakes have large scutes (scales on the ventral side of the animals) and some (Boas) have pelvic remnants as spurs. Advanced snakes have small scutes.
What are amphisbaenians? A group of legless lizards with no scutes. However 3 species in the genus Bipes have front limbs. These lizards are excellent burrowers.
What are the major groups of lizards (above the level of order—e.g. iguania, gekkota, scincomorpha etc)?
Which adaptations are really unusual in lizards? Feet (zygodactylous) and eyes (independent) of chameleons. Amphisbaenids burrowing, glass lizards (limb loss)
Complicated breeding behavior occurs in many lizards. Head bobbing, territorial display and mate attraction.
The really Big lizards are—Varanidae—Komodo Dragon and Monitors
Poisonous lizards—Gila Monster and Beaded Lizard—Helodermatidae are the only poisonous lizards (neurotoxins) in the world. Many snakes on the other hand are poisonous. (Elapids (cobra) , Viperids (rattlesnakes), some Colubrids (like rat snakes but rear fanged and not in the USA)
Geckos—Can walk or crawl anywhere. How? Specialized toe pads.
How do snakes swallow large items? The jaw muscles and ligaments are flexible. Mammals are swallowed head first. The best food for a snake is another snake and the group of snakes that do this feeding are called King Snakes.
List the families of poisonous lizards and snakes. Helodermatidae (Gila Monster), Viperidae (vipers and rattlesnakes), Elapidae (cobra) and weakly toxic the common Colubridae snakes.
What are the major groups of living snakes? Scolecophidia (worm snakes—545 species) alethinophidia (boas, pythons, vipers—442 species ), cobras Elapidae and sea snakes —359 species) , Colubridae (common snakes—have the greatest number of species—1866 species) Some species have rear fangs)
What is the “pit” in pit viper? Function?
Toxins in snakes and lizards have what type of biochemical action? See page 317 for proteinases, hyaluronidase, etc. Vipers/Rattlesnakes use proteinases and cardiac blockers to poison prey while cobras and sea snakes use basic polypeptieds to damage the nervous system. The neurotoxins are the most poisonous in the world.
List the different types of snake fangs. Aglyphous (no fangs),Ophistoglyphous (rear fangs—some colubrids). Solenoglyphous (fangs on a rotating maxilla—Rattlensnakes/Vipers) and proteroglyphous (front fangs—cobra and sea snake) How do they work?).Figure 17.12 page 314
Reproduction: Oviparity—egg layers—many species—no parental care
Viviparity is live birth
Which group of reptiles has the most complicated breeding behaviors? Hint (lizards)
Which groups of reptiles show parthenogenesis? Teids (whiptails), Geckos and some Agamads (old world type iguanids) from Africa. How do they reproduce without a male? No male required so the organisms are clones.
Sex determination. Some species have temperature sex determination (TSD) that we see in Turtles. However TSD (tuatara have tsd) is not nearly as common as what we see in turtles. Some species have sex chromosomes (GSD both ZW and XY) and other are truly parthenogenic or or gynogenetic. It is a big wide world out there in reptile sex determination.
Snakes and lizards have internal fertilization and males have a penis or two as happens in the snakes.
Some lizards show elevated body temperature over ambient conditions. How do they do this? Why do they have elevated body temperature? What is the reason? It is all about higher metabolic rate! And gaining access to food through predation or being a vegetarian like the iguanas in Florida.
Finally many closely related species in the same genus for some lizards show strong niche separation in nature. The anole lizards show strong territorial behavior and niche separation.
Which groups are the most diverse in Lizards? Snakes? The least diverse?
Eyes, ears, tongues, sounds.
Lizards have external auditory openings. Snakes do not. Eyes/eyelids—no snakes have eyelids. The burrowing snakes have very reduced eyes very much like the amphibian caecilians. They have a hard clear spectacle that is shed as the species grows. Many lizards have eyelids but several have a hard spectacle like snakes. All snakes have a forked tongue with a specialized organ in the roof of the mouth for sensing odors. Some lizards have a forked tongue but not all. And finally there are no sounds made by any of the squamates to my knowledge. Tuataras make sounds as do some turtles.
Habitats: Only one species of lizard lives in the ocean, the Galapagos Iguana. It is a vegetarian and has salt glands to control water balance. The cobras of the water, the poisonous sea snakes are the only other snakes in the ocean. Any snake “naturally” in the ocean is poisonous. They all have live birth.
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