question

What replaces the notochord in adult stages of gnathostomes?

answer

intervertebral disks

question

what is one advantage of the evolution of jaws among vertebrates?

answer

The evolution of jaws among vertebrates allowed gnathostomes to become large and voracious predators. (Jaws allow the animal to break large prey items into smaller pieces and process the food for easier consumption.)

question

Which extant animal is the closest living relative (sister taxon) of vertebrates?

answer

Urochordates

question

What are the original and later functions of pharyngeal slits or clefts in chordates? (Include non-vertebrate chordates, "fishes", and terrestrial vertebrates such as mammals.)

answer

The original function of the pharyngeal slits, observed in non-vertebrate chordates (cephalochordates and urochordates) is for filter feeding. In later diverging vertebrates, the pharyngeal slits become the gill slits and supports used in respiration (gas exchange). The pharyngeal slits or clefts in terrestrial vertebrates, such as mammals, contribute tissues to the ear and neck.

question

What is the difference between bone and cartilage?

answer

Bone and cartilage are connective tissues that contribute to the vertebrate skeleton. Cartilage is flexible with an abundance of collagen fibers embedded in chondroitin sulfate, whereas bone is a rigid mineralized matrix of collagen fibers embedded in calcium salts.

question

Provide an example of a countercurrent exchange system in the respiratory system of vertebrates and explain how it works.

answer

One example of a countercurrent exchange system is found in the gill apparatus of fish. Blood within capillaries of the gills flows in an opposite direction than (countercurrent to) water passing over the surface of the gills. The countercurrent allows oxygen from the oxygen-rich water to be transferred to the oxygen-poor blood in an efficient manner. (Other countercurrent exchange systems occur in the limbs of some vertebrates for temperature regulation and in the kidney for water retention and ion concentration.)

question

List four derived characters (synapomorphies) that unite all vertebrates.

answer

(1) myoglobin (oxygen-carrying pigment in muscle), (2) pineal organ (region of brain that is sensitive to light), (3) vertebrae (skeletal elements that surround the spinal cord), and (4) bones & cartilage (connective tissue that supports and protects the body).

question

what are myomeres?

answer

Myomeres are segmented muscle blocks seen in early chordates

question

what are claspers?

answer

Claspers are paired appendages associated with internal fertilization (first observed in placoderms).

question

what is myoglobin?

answer

Myoglobin is an oxygen-storing, pigmented protein in muscle (synapomorphy for Vertebrata).

question

What is paedomorphosis?

answer

Paedomorphosis is the retention of juvenile characteristics in adult organisms (e.g., some adult tunicates remain mobile like the larvae of other tunicate species).

question

What are neural crest cells?

answer

Neural crest cells are cells along the sides of the developing neural tube that migrate to various regions of the organism to form parts of the skull, teeth, adrenal glands, and peripheral nervous system (found in all vertebrates).

question

what is a notochord?

answer

A notochord is a flexible rod that extends along the dorsal edge of the chordate body for support (synapomorphy for all chordates).

question

What is meant by sessile?

answer

Sessile is a mode of life in which the organism is stationary and does not move (observed in most adult tunicates).

question

What is meant by mobile?

answer

Mobile is a mode of life in which the animal moves and does not remain in a single location (observed in most juvenile tunicates and most vertebrates).

question

What is a pineal organ?

answer

The pineal organ or gland is a small gland or region of the brain that is sensitive to light and secretes melatonin (synapomorphy for Vertebrata).

question

What is a neuromast organ?

answer

Neuromast organs are specialized mechanosensory structures that contribute to the lateral line system and detect vibrations in water (first observed in chondrichthyans).

question

What is an operculum?

answer

An operculum is a bony covering that protects the gills (synapomorphy for Actinopterygii).

question

The group to which salmon and trout belong is__________?

answer

Actinopterygii

question

What is the structure(s) used by adult tunicates to capture food?

answer

pharyngeal slits

question

A specialized structure seen in some vertebrates for detecting vibrations in water is called_______?

answer

lateral line system, which includes neuromast cells

question

What are the pros and cons of external and internal fertilization?

answer

external Pros: energetic efficiency and a potential for lots of offspring cons: unprotected offspring (fertilized eggs) and environmental constraints (e.g. frogs need water to lay eggs) internal pros: protection of developing offspring, parental care of young and fewer obstacles between sperm and eggs (easier for gametes to come into contact) cons: energetically expensive (for female at very least) and typically results in fewer offspring

question

List four synapomorphies for chordates.

answer

(1) a notochord (flexible rod that extends along the dorsal side of the animal and provides support), (2) a dorsal, hollow nerve chord (contributes the central nervous system), (3) pharyngeal slits or clefts (function in filter feeding in non-vertebrate chordates, gills for respiration in fish, and contribute tissues to the ear and neck in terrestrial vertebrates), and (4) muscular, post-anal tail.

question

Name the two major monophyletic groups of bony fishes.

answer

Actinopterygii (ray-finned fishes) and Sarcopterygii (lobe-finned fishes

question

Briefly explain the origin of jaws and evidence to support this.

answer

The prevailing hypothesis is that jaws develop from the skeletal support for the pharyngeal slits, and in particular the anterior gill or branchial arch.

question

Describe the circulation of blood in ray-finned fishes.

answer

single circulation; deoxygenated blood from the heart will travel through the gills to accept oxygen and then to the capillaries of the body (where the blood becomes deoxygenated) before returning to the heart

question

How many chambers did the ancestral bony fish heart have?

answer

two chambers - one atrium and one ventricle

question

Are hagfish scavengers or parasites? What about lampreys?

answer

hagfish are scavengers and lampreys are parasites

question

What are conodonts and what is their significance?

answer

Conodonts are the mineralized mouthparts of extinct jawless vertebrates, and they likely represent precursors to teeth.

question

Which came first, lungs or swim bladders?

answer

Lungs were developed before swim bladders in Osteichthyes (bony fish). In fact, swim bladders are modified lungs!

question

Define the term exaptation.

answer

An exaptation is a pre-existing feature that is co-opted for another function

question

Give an example of an exaptation in the context of the water-to-land transition during tetrapod evolution.

answer

An example of an exaptation in the context of the water-to-land transition during tetrapod evolution is the forelimb. The limb was an adaptation for swimming in sarcopterygians (lobe-finned fishes) that later was co-opted for walking on land.

question

What is the difference between the traditional and current concepts of the relationship between birds and reptiles?

answer

Under the current concept, Reptilia (including birds) is monophyletic. Under the traditional concept, Reptilia (excluding birds) is paraphyletic. Traditionally, birds are classified separately from reptiles, such as turtles, lizards, and crocodiles, based on anatomy. Birds have feathers, warm blood, and they fly, whereas the other animals have scales, cold blood, and are confined to the Earth's surface. The current concept of those relationships is based on common ancestry. Birds are descendants of the most recent common ancestor of turtles, lizards, and crocodiles; therefore, birds are reptiles.

question

Discuss blood-circulation and the anatomy of the heart in fish, amphibians, and non-avian reptiles.

answer

Fish have hearts with two chambers (one atrium and one ventricle) and single circulation of blood through the body. After the blood is oxygenated by the gills, the blood flows through the rest of the body before returning to the heart. In amphibians, the heart has two chambers (two atria and one ventricle) and double circulation. After receiving oxygen from the lungs, the blood returns to the heart, which pumps it through the body before returning to the heart. In some reptiles, the ventricle is either partially or fully divided creating four chambers in the heart. Along with double circulation, oxygenated and deoxygenated blood is kept separate.

question

Review three problems and solutions that vertebrates encountered moving from the water to the land.

answer

Respiration - terrestrial vertebrates must receive oxygen from the air rather than water; this problem is overcome through the evolution of lungs (specialized air sacs), choanae (internal nostrils), and cutaneous respiration (breathing through skin). Support and Movement - gravity has a greater effect on the body and locomotion on land than it does in water; this problem is overcome by strengthening of the pectoral and pelvic girdles and limbs, including presence of fingers and toes. Senses - the special senses, such as hearing, function differently in air than in water; in the case of the ear, this was overcome by the origin of the tympanic membrane (ear drum) and columella (stapes). Water Retention - terrestrial animals are at risk from dehydration; water is retained in kidneys and intestines, and waste products are concentrated as urea (mammals, most amphibians) and uric acid (reptiles) to aid in elimination. Reproduction - occurs in the water for most species, especially the laying of eggs; most terrestrial vertebrates employ internal fertilization, amphibians develop through metamorphosis during which juveniles are aquatic and adults are terrestrially adapted, and amniotes have developed the amniotic egg that can be laid away from the water.

question

Discuss two hypotheses that have been proposed to explain why vertebrates moved onto the land.

answer

Hypotheses that have been proposed to explain why vertebrate may have moved to aquatic habitats include avoidance of competition, exploitation of new food sources, access to atmospheric oxygen, and perhaps escape from predators.

question

Name and list the function of each of the membranes of the amniotic egg and discuss its significance to amniotes.

answer

Amnion - fluid filled sac that cushions the embryo Allantois - waste disposal system for the embryo, and it participates in gas exchange Chorion - main site of gas exchange between the air and the embryo Yolk sac - contains the yolk (food supply) and is covered with blood vessels from the transport of nutrients Albumen - "egg white" that protects the yolk and provides additional nutrients Shell - leathery or calcified layer that gives protection and allows gas exchange

question

Why might tuataras deserve a higher conservation priority than snakes?

answer

Tuataras are the last living members of an ancient lineage. Thus, if they were to go extinct, there are no close relatives and a unique branch of biodiversity will disappear forever.

question

Give a vertebrate example of a non-monophyletic group. What's wrong with recognizing non-monophyletic groups?

answer

The traditional classification of birds (Aves) as separate from reptiles (Reptilia) is a classic example of non-monophyly (or paraphyly) given that birds are descended from the most recent common ancestor of all other living reptiles. Not recognizing monophyletic groups potentially misrepresents evolutionary history - a central foundation of the biology of organisms.

question

What major transition did amphibians never make that was made by amniotes?

answer

Amphibians never completely cut their ties with aquatic habitats. Amphibians must have water to breed and lay their eggs. However, with the evolution of the amniotic egg, amniotes were able to move away from the water and exploit new habitats.

question

What was Tiktaalik and what was its significance?

answer

Tiktaalik was a transitional sarcopterygian "fish" that possessed features that were both fish-like (scales, fins, gills, and lungs) and tetrapod-like (neck, ribs, bones in the fin, flat skull, eyes on top of head).

question

What was Ichtyostega and what was its significance?

answer

Icthyostega was one of the first true amphibians with a fully developed tetrapod limb and seven toes (although reduced to five in more derived taxa).

question

What is the evidence to support the claim that dinosaurs were warmblooded? What about coldblooded?

answer

Evidence for coldbloodedness (or ectothermy) in dinosaurs is in part phylogenetic given that most other archosaurs (e.g., crocodilians) are ectothermic, and dinosaurs lack respiratory turbinates that reclaim moisture in warmblooded animals. Evidence for warmbloodedness (or endothermy) in dinosaurs includes the observation that extant descendants (birds) are endothermic, fossils discovered in polar regions (e.g.,g Australia and Antarctica), limbs are positioned under body indicating vigorous locomotion, and bird-like respiration.

question

Discuss what is meant by oviparous and viviparous.

answer

Oviparous vertebrates lay eggs, whereas viviparous vertebrates give live birth.

question

Discuss how a buccal pump works and what it is used for.

answer

The "buccal pump" is a behavior in anuran amphibians (frogs) that is used in respiration and vocalization. The floor of the mouth is depressed when the mouth is closed, which causes air to be drawn into the nostrils. The nostrils are closed as the floor of the mouth is elevated, thereby forcing the air into the lungs. The oral (mouth) cavity is ventilated by opening the nostrils, and the lungs are emptied through contractions of the abdominal wall and recoil of the lungs.

question

Differentiate between temperature regulators and conformers.

answer

Temperature regulators possess internal mechanisms to control body temperature (e.g., metabolism), whereas temperature conformers utilize external factors to control body temperature (e.g., ambient temperature).

question

What are the costs and benefits for internal temperature regulation?

answer

The costs of temperature regulation include increased energy expense and a high food requirement for active metabolism. However, the benefits include an ability to perform vigorous activities for long periods of time (e.g., running, swimming, and flying), as well as the ability to function in fluctuating environments and temperatures.

question

Describe the anatomical difference between anapsid, diapsid, and synapsid amniotes.

answer

Amniotes possess a variety of fenestrations (windows) in the temple regions of the skull. In the anapsid condition, which is observed in turtles, there are no windows or fenestrae in the temple. In the diapsid condition, which is observed in lizards, there are two fenestrae in the temple. In the synapsid condition, which is observed in mammals, there is only a single fenestra.

question

Identify the members and discuss the anatomy and lifestyles of the major clades of Reptilia.

answer

Temperature sex determination means that the temperatures at which eggs incubate determine the genders of the developing embryo. This phenomenon is observed in some turtles, lizards, and crocodilians.

question

Discuss three different hypotheses for the relationships of turtles to other reptiles and the type of evidence that supports each.

answer

Fossil evidence suggests that turtles are the living descendants of early anapsid reptiles. However, some anatomical evidence from the skull suggests that turtles are the sister taxon of archosaurs, whereas most DNA evidence suggests that turtles are most closely related to lepidosaurs (lizards, snakes, and tuataras).

question

isometric growth

answer

Isometric growth is growth in which scaling is proportional (juveniles individuals look like miniature versions of adults).

question

allometric growth

answer

Allometric growth is growth that is not proportional (different body parts grow at different rates).

question

homeotic genes

answer

Homeotic genes are master regulatory genes that control placement and spatial organization of body parts.

question

macroevolution

answer

Macroevolution is evolution above the species level.

question

actin

answer

Actin is thin protein filaments that interact with myosin within the sarcomeres of skeletal muscle.

question

myosin

answer

thick protein filaments that interact with actin within the sarcomeres of skeletal muscle.

question

gray crescent

answer

The gray crescent is the region of the fertilized egg that forms opposite the point of entry of the sperm and ultimately becomes the dorsal surface of the embryo.

question

blastopore/ primitive streak

answer

The blastopore (in the frog) and the primitive streak (in the chick) are sites of invagination in the gray crescent that initiates gastrulation.

question

neurulation

answer

organogenesis of brain and spinal cord. the formation of the notochord by cells of mesoderm

question

somites

answer

Somites are regions of the developing embryo that form lateral to the notochord and play an important role in organizing the segmented structure of the body in vertebrates.

question

cursorial

answer

running

question

graviportal

answer

heavy bodied stance to move large mass

question

fossorial

answer

digging

question

saltation

answer

hopping

question

brachiation

answer

arm swinging

question

scansorial/arboreal

answer

climbing

question

volant

answer

active flight

question

gliding

answer

passive flight

question

furcula

answer

The furcula is the fused clavicles present in theropod dinosaurs, including living birds; probably an exaptation for flight.

question

pygostyle

answer

The pygostyle is the bone at the tip of the tail in birds that helps to anchor tail feathers; probably and adaptation for flight.

question

Define heterochrony and provide an example of how it can cause the evolution of different body forms.

answer

Heterochrony refers to differential timing in development. Heterochronic changes can lead to adaptations for novel habitats. (E.g., paedomorphosis in salamanders allows adults to live a fully aquatic life; prolonged development of the digits in some salamanders allows a more terrestrial lifestyle.)

question

Provide an example of how a change in the spatial pattern of body parts lead to substantial evolutionary changes.

answer

Alterations of genes controlling the positions of body parts can lead to substantial evolutionary changes, such as evolution of paired limbs in gnathostomes or the numbers of digits in tetrapod limbs. (E.g., the chicken wing has only four digits.)

question

How might gene duplications lead to substantial evolutionary changes in vertebrate evolution?

answer

Gene duplications allow mutations in a duplicated sequence that may lead to new developmental genes, without affecting the function of the original sequence.

question

How does a change in gene regulation differ from a change in gene sequence?

answer

a change in gene regulation are changes in how genes are expressed, but not the gene sequences themselves.

question

How does gastrulation differ between frogs and chickens?

answer

In the frog, the blastula is several cells thick and the blastopore originates at the gray crescent. Gastrulation begins as cells invagniate (fold in) at the blastopore. The blastula of the chicken, which sits upon a large yolk cell, is only two layers thick (epiblast and hypoblast). During gastrulation, the epiblast moves towards the midline and invaginates, forming the "primitive streak" (equivalent to the blastopore in frogs).

question

What is the difference between cellular determination and differentiation?

answer

Cell determination is a process when the fate of a cell is determined. Cell differentiation results in specialization

question

From which of the three germ layers does the notochord develop? How about the neural plate (which becomes the dorsal hollow nerve cord)?

answer

notochord develops from the mesoderm. neural plate forms from the ectoderm. the notochord becomes the dorsal hollow nerve cord

question

Which region of the developing embryo is considered the "organizer" of the embryo's body plan?

answer

The "organizer" of the embyro's body plan is the dorsal lip of the blastopore (discovered by Hilde Mangold and Hans Spemann through developmental experiments on the blastopores of newts).

question

Explain how developmental biologists determine the eventual fates of cells within a developing blastula. (I.e., how do we know which cells will eventually contribute to the tail of a salamander?)

answer

Fate mapping: general territorial diagram of embryonic development. They also fat map by dyeing different cells in blastula reveals different fates (??)

question

Explain how a third class lever system works and provide an example of one in your body. (Note: you may need to know how the other levers work for the upcoming quiz and final exam.)

answer

In a third class lever, the in-force is located between the out-force and the fulcrum of the joint. The third class levers is the most common type of lever in the vertebrate body. One example is the elbow.

question

Explain the "Sliding Filament Model" of muscle contraction, and identify which of the following structures (more than one) is shortened during the process: thick filaments (myosin), thin filaments (actin), sarcomere, myofibril, muscle fiber (cell).

answer

The "sliding filament model" explains the contraction of the muscle. During contraction, parts of the thick filament (myosin) pulls on the thin filament (actin) thereby shortening the sarcomere. The thick and thin filaments remain the same length during contraction, but the sarcomeres are shortened, which in turn shortens the myofibril, which in turn shortens the muscle fiber (cell), which in turn shortens the muscle.

question

What is the relationship between force and velocity, and how can a limb be modified to increase each one?

answer

Force is the effort applied or exerted, and velocity is the speed and direction of the applied/ exerted force. If the muscle is moved away from the joint (fulcrum), then the in-force is increased thereby increasing the out-force. Out-force is increased if the out-lever is shortened as well. If the muscle is moved closer to the joint, the velocity of the in-force is increased, thereby increasing the out-velocity. Out-velocity is increased if the out-lever is lengthened as well.

question

Describe the adaptations of plantigrade, digitigrade, and unguligrade limbs in cursorial vertebrates.

answer

elements in touch with ground are reduced in number Plantigrade: soles (ex: squirrel) Digitigrade: toes and fingers (ex: dog) Unguligrade: tips of toes (ex: deer)

question

Between volancy, cursoriality, and natation, which type of locomotion is most energetically efficient? Which is most energetically expensive?

answer

At any given body mass, natation (swimming) is the most efficient and cursoriality (running) is the least efficient.

question

From which specific reptilian lineage did modern birds descend? (Be as specific as possible).

answer

Modern birds (Aves) and members of Theropoda, which is a member of Saurischia, which is a member of Dinosauria, which is a member of Archosauria.

question

How does respiration in a bird differ from that of a mammal?

answer

Respiration in birds invlolves a unidirectional flow of air through the lungs. The unidirectional flow is facilitated by air sacs, many of which intrude into their hollow bones. In contrast, air flows in two directions in mammals (in and out through the same passages).

question

How is flight in bats similar to flight in birds, and how are they different?

answer

Both bats and birds employ powered, active flight (volancy). However, birds use the entire forelimb to generate the force and feathers to generate lift. In contrast, bats use elongated digits on their hands (fingers) to generate force and wing membranes to generate lift.

question

Are the furcula (wishbone), hollow bones, and feathers adaptations or exaptations for flight? How do you know?

answer

The furcular (wishbone), hollow bones, and feathers are exaptations for flight. That is, they evolved before active flight evolved in birds and their closest ancestors. We know that those features are exaptations for flight (and not adaptations) because they were present in non-avian theropods that clearly were incapable of flight (passive or active).

question

Discuss the two hypotheses regarding how powered flight evolved in birds. What evidence supports each hypothesis?

answer

In the "trees-down" hypothesis, the immediate ancestors of birds lived in trees. Wings and feathers would give the animals balance, and moving from tree to tree would be energetically efficient. Some of the closest ancestors of modern birds had long digits and sharp claws that appear to be adapted to life in the trees. In the "ground-up" hypothesis, hind limbs develop for speed and the forelimbs are lengthened for grasping prey (similar to a flight stroke). Feathers that were already present on limbs would provide a little lift and facilitate chasing prey. Evidence for this hypothesis is that the long limbs and feathers are already present in non-volant theropods.

question

diphyodont

answer

only two sets of teeth that characterizes most mammals

question

monophyodont

answer

only one set of teeth that characterizes a few mammals

question

altruism

answer

behavior that benefits other individuals at the expense of the individual displaying the behavior

question

heterodont

answer

different types of teeth in the same set of jaws that serve different functions

question

ethology

answer

study of behavior

question

homeothermic

answer

a constant body temperature is maintained (found in mammals and birds)

question

trophoblast

answer

outer layer of the blastocyst in mammals that forms an active barrier between the embryo and mother, and stops immunological rejection by producing hormones to prolong gestation

question

sign stimulus

answer

external trigger for a behavior

question

indirect fitness

answer

the ability for an individual's relative to survive and reproduce (direct fitness is the ability for an individual to survive and reproduce)

question

tidal volume

answer

volume of air brought in and out of the lungs during normal respiration

question

eusociality

answer

non-reproducing individuals rear the offspring (e.g., bees, naked mole rats, etc.)

question

vibrissae

answer

tactile sensory hairs of mammals, commonly known as "whiskers"

question

Explain the optimal foraging model.

answer

The optimal foraging model refers to maximizing benefits of obtaining food at the lowest cost. For example, birds that drop mollusk shells in order to break them will drop the shells from the lowest elevation needed. (It would cost more energy than is needed to drop the shells from a higher elevation.)

question

Give specific examples of innate versus learned behavior.

answer

Innate behaviors do not need to be learned or practiced, but rather have a genetic basis. Examples include reflexes, such as a fixed action pattern (unlearned response to a stimulus), or instincts, such as migration. A learned behavior has been modified based on specific experiences, such as spatial and associative learning.

question

Why is egg laying in monotremes not considered an apomorphy (derived characteristic) for the group?

answer

Egg laying (ovipary) is not an apomorphy, or derived characteristic, for monotremes because it was a physiology that was inherited from a distant ancestor (shared with reptiles). In order for it to be an apomorphy it would have to be derived.

question

What is altruistic behavior and how might it be related to kin selection?

answer

An altruistic behavior benefits other individuals at the expense of the individual displaying the behavior. Altruistic behaviors may increase an individual's indirect fitness, or the fitness of a relative (given that related individuals share genes). Kin selection is selection that favors the spread of genes through indirect fitness (survival and reproduction of a relative); thus altruistic behaviors may factor into kin selection.

question

What is meant by the ultimate cause of behavior? Give an example.

answer

The ultimate causation of a behavior is "why" a behavior occurs, such as an influence on survival and reproduction. Examples include the optimal foraging model and mating systems.

question

What is the hypothesis for the original function in hair of mammals?

answer

The original function of hair likely was for tactile sensations (i.e., vibrissae or whiskers) and later exapted for thermal regulation (insulation).

question

What is meant by the proximate cause of behavior? Give and example.

answer

The proximate causation of a behavior is "how" a behavior occurs, such as the stimulus and physiological response. Examples include fixed action patterns, environmental stimuli (such as circadian rhythms), communication, and learning.

question

Describe and distinguish the patterns of reproduction in monotreme, marsupial, and placental mammals.

answer

Monotreme mammals lay amniotic eggs (oviparous), but they are held inside the mother for a longer period of time than reptiles for a nutrient exchange. Marsupial mammals give live birth (viviparous) and develop a "chorivitelline" placenta between the chorion and yolk sac. Gestation is shorter than in placental mammals, and the young are born altricially and most finish development in a pouch. Placental mammals give live birth (viviparous) and develop a "chorioallantoic" placenta between the chorion and allantois. Gestation is longer than in marupial mammals, and the young are born precocially and complete development within the uterus.

question

What are the evolutionary and developmental origins of the three mammal middle ear bones (ossicles)?

answer

Evolutionarily, the three middle ear bones in mammals are derived from bones in the lower jaw of other vertebrates. During mammal development, the bones that eventually become the middle ear bones are attached to the lower jaw and migrate to the middle ear in adults.

question

Describe three major anatomical or physiological changes in deep diving mammals.

answer

Lungs collapse and alveoli are emptied; high concentration of oxygen in muscle (high myoglobin content); higher blood volume (increased blood oxygen) redistributed among tissues; heart rate slowed

question

What type of amniotes are mammals based on the temporal fenestration pattern of their skulls?

answer

Mammals are considered to be synapsid amniotes (Synapsids).

question

explain the three processes that occur in the mammal kidney.

answer

Filtration - blood pressure forces fluid into Bowman's capsule of the nephron (functional unit of the kidney) Reabsorption - minerals and ions actively and passively transported back into the blood Secretion - hydrogen and potassium transported back into the tubules of the nephron

question

Why is the mammal kidney referred to as a countercurrent exchange multiplier?

answer

The kidney is a countercurrent exchange system in that fluid with different concentrations of NaCl (salt) flow concurrently past one another. The kidney is a countercurrent exchange multiplier in that NaCl is actively transported into the blood to regulate osmolarity differences within the kidney.

question

How are precocial young different from altricial young?

answer

Precocial young (characterizes placental mammals) are born at a later stage of development and altricial young (characterizes marsupial mammals) are born at an earlier stage of development.

question

the differences between the choriovitelline and chorioallantoic placentas and identify which major clade of mammals possesses each type.

answer

The choriovitelline placenta, which is developed in marsupial mammals, is formed between the chorion and yolk sac, and it offers the embryo limited services for a short period of time. The chorioallantoic placental, which is developed in placental mammals, is formed between the chorion and the allantois, and it offers all necessary services for a long period of time.

question

What does it mean that "mammals are homeothermic endotherms that maintain a relatively high body temperature"?

answer

Homeothermic refers to the ability to maintain a constant body temperature (as opposed to poikilothermy, which is changing body temperatures). Endothermy is the internal regulation of body temperature (as opposed to ectothermy, which is temperature conforming). The typical mammal maintains a body temperature higher than other non-mammalian vertebrates. Thus, mammals regulate and maintain a high body temperature.

question

sustainable development

answer

Sustainable development is development that meets the needs of people today without limiting the ability of future generations to meet their needs.

question

Hominins

answer

Hominins contribute the branch of the primate tree (phylogeny) that includes modern humans and extinct primates that are more closely related to modern humans than to chimpanzees.

question

Bipedalism

answer

Bipedalism is locomotion on two legs (as opposed to quadrupedalism that is the ancestral style for tetrapods).

question

Biological Magnification

answer

Biological magnification is retained substances become more concentrated at each higher trophic level in a food chain.

question

What does the following commentary by a noted biologist refer to: "mankind stood up first and got smarter later"?

answer

The statement refers to evidence from the fossil record of human ancestors that bipedalism ("mankind stood up") evolved before an increase in brain size ("mankind got smarter").

question

Do humans share a more recent ancestry with Old World monkeys or New World monkeys?

answer

Humans share a more recent common ancestry with Old World monkeys than New World monkeys.

question

What is meant by the latitudinal diversity gradient and where does the greatest diversity occur?

answer

The latitudinal diversity gradient refers to the increase in species moving from high latitudes (the poles) towards lower latitudes (the equator). The greatest diversity occurs in tropical regions.

question

What is the greenhouse effect, and what can we do about it?

answer

Most solar radiation is reflected off the Earth's surface and directed into space. However, increased carbon dioxide (CO2) and other gases in the atmosphere trap the solar radiation in the Earth's atmosphere and leads to increases in temperature. Global warming can lead to disappearance of polar icecaps and continental glaciers, and bleaching of coral.

question

What are three ways humans are negatively impacting the environment and what are solutions to each of these challenges?

answer

Humans are causing an increase in atmospheric carbon dioxide (CO2). This can be overcome by reducing our carbon emissions (e.g., increase fuel economy). Humans introduce pesticides into the environment. The toxins accumulate in tissues and are compounded across trophic levels (biological magnification). This problem can be overcome by utilizing natural pesticides. Habitat destruction negatively affects species. Protection of habitats is more efficient than protecting species, and adoption of sustainable development can protect biodiversity.

question

Does available evidence indicate that Homo florisiensis is a new dwarf human or an abnormal (diseased) modern human species (Homo sapiens)?

answer

Evidence from the wrist and ankle bones suggests that Homo florisiensis was a separate species from Homo sapiens and not a deformed population of modern humans.

question

Why is it inappropriate to think of early hominins as chimpanzees or as having evolved from chimpanzees?

answer

Chimpanzees and hominins (including modern humans) are descended from a common ancestor, and both fall along separately evolving lineages. Both chimpanzees and hominins have independently acquired derived features after diverging from their common ancestor.

question

What is the current world population?

answer

Current world population is over 7.2 billion people!

question

Which lineage of the great apes is most closely related to humans?

answer

Chimpanzees are the closest living relatives of humans.

question

What is the geologic age of the oldest hominin fossil? What is the geologic age of the oldest Homo sapiens (modern human species) fossil?

answer

The oldest hominin fossil is ~6.5 million years old. The oldest Homo sapiens fossil is ~195,000 years old.

question

What is the evolutionary relationship between Neanderthals and Homo sapiens (modern human species)?

answer

Genetic evidence suggests that Neanderthals and Homo sapiens are descended from a common ancestor and modern humans did not evolve from Neanderthals. However, a small amount of gene flow did occur between the species.

question

Chordate pharyngeal slits appear to have functioned first as:

answer

suspension-feeding devices

question

Arrange these taxonomic terms from the most inclusive (most general; largest group) to the least inclusive (most specific; smallest group): 1. Sarcopterygii 2. Actinistia 3. Gnathostomata 4. Osteichthyes 5. Chordata

answer

5,3,4,1,2

question

A trend first observed in the evolution of the earliest tetrapods was

answer

feet with digits (toes)

question

You believe that you have found a fossil representing the most recent common ancestor of chondrichthyans and osteichthyans because it possesses:

answer

lateral line system, paired appendages, gills

question

Which of the following correctly describes the circulatory system of the indicated vertebrate?

answer

the fish heart possesses two chambers (one atrium and one ventricle) and a single circulation of blood through the body

question

Mineralized tissues in vertebrates appear to have functioned first as:

answer

mouthparts for scavenging or predation

question

You have discovered a new species of vertebrate while swimming at La Jolla Cove! Your species has the following characteristics: well-developed jaws with mineralized mouthparts, bony vertebrae, and paired appendages, but it lacks any evidence of a choana. Which of the following features would absolutely not be present in your new vertebrate?

answer

fingers and toes at the end of the limbs

question

Which of the following is not an osteichthyan? lungfish tiger ray-finned fish great white shark lobe-finned fish

answer

great white shark

question

Gas exchange efficiency between blood and water is increased by the gills of fish through:

answer

a counter-current flow of blood and water

question

Members of which of the following groups have both lungs and gills during their adult lives?

answer

lungfish

question

Arrange the following developmental events in the proper order from earliest to latest: 1. cleavage 2. fertilization 3. gastrulation 4. organogenesis

answer

2, 1, 3, 4

question

When skeletal muscle contracts, the actin and myosin filaments:

answer

slide past one another

question

The closest living relatives to endothermic birds are:

answer

ectothermic crocodylians

question

Manakins are small perching birds from South and Central America, and they exhibit sexual dimorphism in plumage color like many other birds. That is, the males tend to be more brightly colored than the females, and this contributes an important component to their mating system. In one particular species, the long-tailed manakin (Chiroxiphia linearis), males retain their juvenile plumage into adulthood, but will eventually lose the juvenile coloration at a greater stage of maturity than is observed in other manakin species. This phenomenon is known as:

answer

paedomorphosis

question

Which of the following is a reptile with an anatomically four-chambered heart (fully divided atria and ventricles)?

answer

crocodile

question

Birds have higher caloric needs than do non-avian reptiles of comparable body size because they:

answer

are endotherms

question

Cichlids are a group of teleost fish that have received a great deal of attention from evolutionary biologists, in part because of a rapid adaptive radiation that has led to an extreme diversity in the fishes' habitats and diets. Genetic studies have identified that South American species have 48 chromosomes, but African species only possess 44 chromosomes. Mutations within the duplicated chromosomes of the South American species may have led to the success and diversification of those species. Such a scenario can describe macroevolution in cichlids (in part) through:

answer

gene duplication

question

Which of the following features distinguishes turtles from all other non-avian reptiles?

answer

plastron

question

In a chicken embryo, gastrulation:

answer

occurs as cells along the primitive streak invaginate towards the yolk

question

What is the proper positional relationship among the in-force, the out-force, and the fulcrum in a first class lever?

answer

the fulcrum is positioned between the in-force and the out-force

Bio 204 Vertebrates HW – Flashcards

Unlock all answers in this set

Haven't found what you were looking for?

Search for samples, answers to your questions and flashcards