Date: Life Sciences and Biological Considerations

Posted: November 30th, 2013




Life Sciences and Biological Considerations

1. Evolution provides the basis of innovation in vertebrate body design for their survival on earth. The innovation has mainly manifested itself on existing structures by giving them new functions, and this has been the most notable feature of evolution in vertebrates. One major innovation includes change of front fins to limbs. This is explained through the theory of a fish referred to as lobefins that crawled to land. Evolution dictated that the fins of this fish had to change into limbs for their survival (Johnson, David, and William Brett, 52). The other major innovation lies behind the evolution of the vertebrate brain. This evolution ensured that the brain assumed control over the entire nervous system. Consequently, natural selection facilitated the development of key sense organs in the brain.

2. a). Primarily, Myxinoidea and Petromyzontida have the common name hagfish and lamprey respectively.

b). Their feed source includes polychaete worms and dead or dying fish.

c). The feeding mechanism of Myxinoidea involves attaching themselves to dead or dying fish using their suction cup like, barbell adorned mouth to drill a hole into their host and such up fluids and tissue. Petromyzontida feed in a similar way.

d).In terms of development characteristics, both Myxinoidea and Petromyzontida, share the same classification characteristic of jawless fish. Their other development characteristic involves their feeding mechanism where they attach themselves to their hosts and feed on fluids and tissue.

e). Similarly, both Myxinoidea and Petromyzontida have a characteristic eel-shaped body with unpaired fins. They attain balance through their fins and a lateral line that constitutes open pores capable of detecting disturbances in the water to achieve balance.

f.) For Myxinoidea, the notochord includes rods of living cells that lie ventral to the CNS (Central nervous system) and dorsal to the alimentary canal. The notochord in Petromyzontida acts as the main axial skeleton and bears an early stage cartilaginous vestige. This characteristic makes Petromyzontida the most primitive of all vertebrates.

3a. Stingray

b. Shark

c. Seahorse

d. Juvenile rhizodont

4. Class amphibian is divided into three main orders. These include Salientia (anura), Urodela (caudate), and Gymnophiona (Apoda) (Johnson, David, and William Brett, 65). Anura includes toads and frogs; caudate includes newts, salamanders, mudpuppies, amphiuma and sirens. These three types of amphibians fall under one class but possess several distinguishing characteristics. Salientia do not have skin but rather have scales. Members of class Salientia are capable of breathing through their skin as well as their lungs. The form of fertilization in this class involves external form. This implies that fusion of male and female reproduction cells occur outside the female’s body. Members of this class possess four limbs. The front limbs are short with the hind limbs long and webbed. They are used for climbing, leaping, and swimming. Two examples of vertebrates in this group include toads and frogs.

Members of the Urodela class are characterized with smooth glandular skin covering. Similar to members of the Salientia class, Rodela group members breathe through the skin as well as their lungs. Fertilization in this class occurs internally; fusion of the male and female gametes occurs inside the body of the female. Members of this class possess front and hind limbs. The limbs exhibit approximate similarity in terms of size and shape. Two examples of members from this class include salamanders and newts.

The final group of the amphibian class is order Gymnophiona (Apoda). Members of this group possess scale body covering. This makes them the only amphibian group of the three to have such body covering. Respiration occurs through the skin as well as lungs. Fertilization in members of this group occurs internally; fusion of the male and female gametes occurs inside the body of the female. Fertilized eggs are deposited in areas of aquatic nature. Their eggs dry up rapidly therefore, the need of a moist environment. Members of this group have elongated bodies and do not possess any limbs. They are adapted to burrowing and thus spend large parts of their life cycle underground.

5. The student was able to observe a number the common terms of the Pleurodita and Cryptodira reptilians he saw. One common term is that, they are both monophyletic. Secondly, they exhibit the same quality of having scale skin and an external shell. They possess limbs with approximate, similar size and shape. Reproduction occurs internally, and they lay eggs where the offspring hatch. Respiration in both occurs in lungs located inside the ribcage.

6. The first anatomical relationship between birds and dinosaurs rests with the consideration that birds are feathered reptiles. Similar to dinosaurs, birds have scales since feathers are made up of the same matter than makes up scales. Similar to dinosaurs, birds reproduce by laying eggs. There is fair similarity that lies with the soft anatomy of the heart, brain, and other organs between birds and dinosaurs. Evolution also suggests that birds are related to dinosaurs. Pala ontological evidence found dinosaur remains that exhibited birdlike qualities.

7a. Placental mammals are characterized embryo development that occurs in the uterus. The second characteristic maintains that the embryo is nourished through the placenta until birth.

b. The remaining examples of monotremes are only found in New Guinea and Australia. Fetal development occurs in eggs. Examples include duck billed platypus and spiny anteater. Marsupials are predominantly located in the Southern Hemisphere of the globe mainly Australia. Examples include kangaroo and koala bear. The primary location of fetal development occurs externally in the pouch situated at the abdomen. This group is not restricted and occupies numerous types of habitats in all world parts. The primary location of fetal development occurs in the uterus. Examples include cow and dog.

8. Order Cetacea has the scientific name cetus. Example includes whale, dolphin, and porpoise.

Order Artiodactyla has the scientific name Antilocapra Americana. Examples include goat, cow, and sheep. Third order is referred to as Carnivora with the scientific name Carnivora Canidae. Examples include lion, dog, and cat. The fourth order is referred to as Rodentia with the scientific name Hydrochaeris hydrochaeris (Johnson, David, and William Brett, 57). Examples include rat, mouse, and possum. The fifth order is referred to as Primates with the scientific name Catrol Vancliechin. Examples include man, monkey, and gorilla.

9a. The rat, of the four, would have the most predators. This is because its lifestyle and small size leave it exposed and defenseless thus leaving it vulnerable.

b. The rat would also have the easiest time surviving the drought. It is well adapted to these conditions and can live off small amounts grains. It is also capable of metabolizing moisture from those grains.

c. The Kudu is most affected by gravity since it is heaviest in the group.

d. The kudu would lose heat the slowest due to its low surface are to volume ratio.

10a. These forces include lift, drag, weight, and thrust.

bi. Lift and drug forces would increase. This is because a tornado exhibits an increase in velocity.

ii. The force of weight would increase due to the rise in body mass.

iii. The force of drug and thrust would be affected due to the change in streamline shape and reduction in air displaced by wing flaps.

iv. The force of drag and weight will be affected. The added weight adds to viscous drag as well as mass.

11a. The vestibular tissues of the monkey would be affected due to the altered endocrine and metabolic changes subjected by the weightlessness that occurs in space. This implies that the monkey may undergo disorientation and having difficulty sensing organs such as legs or arms.

b. Muscle tissue will respond from the mechanical stress of constant digging. Their reaction will signal imminent stop of the activity due to fatigue.

12. The rib and clavicle would be in a better position to withstand compressive force compared to the femur and radius respectively. This comes from their curved nature that would allow further bending.

13. The sinking problem of the shark can be traced to an injury or disease affecting its swim bladder. The swim bladder is an organ assuming the shape of a two-lobbed balloon (Johnson, David, and William Brett, 82). This organ is responsible for allowing the shark to control its buoyancy or position in the water.


Works Cited

Johnson, David, and William Brett. ” Life Sciences: Biological Considerations.” Bioscene: Journal of College Biology Teaching. 31.2 (2005): 14-134. Print.


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