Natural Science Exam Essay Minimum 2500 Words

Notes: Although there is a minimum word count of 2500 words for the entire exam , you will find that it is likely going to require more than the minimum to fully answer the questions. You may not copy or quote from any source. All information must be re-written in your own words

Question 1: Osmoregulation and Excretion

Describe the principles of diffusion and osmosis across cell membranes and how organisms maintain an optimal internal fluid environment. Include in your answer:

a. the mechanisms by which freshwater paramecia rid their bodies of excess water

b. how invertebrates maintain osmotic balance and waste removal using flatworms, annelid worms, insects, and hemichordates as examples

c. the general mechanisms of salt balance and metabolic waste removal in the kidney of a terrestrial vertebrate

d. a description of the special functions of the “multiplier effect” of mammalian kidneys and of the hormone ADH in regulating salt and water balance

Question 2: DNA Structure and Function

Describe the evidence for the fact that DNA is the genetic material and the sequence of events leading from the sequence of nucleotides of DNA to the sequence of amino acids in proteins and their secretion. Include in your answer:

a. the early evidence for the location of genes on chromosomes, the first evidence that DNA was the genetic material, and that genes determined the structure of proteins

b. a description of the mechanisms of transcription and translation

c. a description of the cellular structures involved protein synthesis and secretion

Question 3: Structural Materials and Terrestrial Locomotion

Describe the fundamental characteristics of structural materials produced by animals and how these materials meet their functional requirements for tetrapod locomotion on land. Include in your answer:

a. the definitions of (1) stress, (2) strain, (3) stiffness, (4) plastic, (5) elastic and (6) strength while comparing spider silk protein and synthetically produced nylon and rayon,

b. physical principles of terrestrial locomotion,

c. the advantages conferred by various adaptations of legs and arrangements of tendon and muscle, and

d. the differences in locomotory patterns of the cat, horse, giraffe, and human and how architecture contributes to the “spring in your step”.

Question 4: Tides and Intertidal Animals

Describe the cause of tides and the adaptations of animals that live in the intertidal zones. Include in your answer:

a. a description of the causes of tides and the zonation that results

b. the adaptations of animals that allow them to survive in each of the tidal zones

C. the mechanisms employed by animals that capture and feed on “small food”

Question 5: Fossil Evidence for “Warm-bloodedness”

Compare and contrast the fossil evidence that leads paleontologists to believe that dinosaurs and the early ancestors of mammals were “warm-blooded”. Include in your answer:

a. the definitions of homeotherm, poikilotherm, exotherm, and endotherm and how these terms are applied to a variety of animals

b. a description of the nature of fossil evidence that is presumed to indicate “warm-bloodedness” in dinosaurs and mammals and describe why paleontologists associate that evidence and the functions of fossilized structures with “warm-bloodedness”.

References Immediately following the essay, two lines below the last line of your last answer (do not skip to a following page), list all sources used in writing your essay to answer the question. Do not use in-text citations and do not use footnotes. Simply list your sources in this “References” section. You must have a References section with at least five references which you have used in preparing your answers