Animal Structure and Function

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Animal Structure and Function
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Keywords importance of size, scaling, collagen,
ascorbate, hydroxyproline

• Reading Ch. 40 in Campbell 6th edition

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Why study biology?

• Some thoughts

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• Macintosh 1984
• 2599
• 128 kb RAM

• 2.5GHz Intel Core 2 Duo
• 2GB memory
• 250GB hard drive1
• Double-layer SuperDrive
• NVIDIA GeForce 8600M GT with 512MB

2,499.00
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Manual DNA sequencing

• Automated DNA sequencing

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The Challenger Expedition 1872-1876
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(No Transcript)
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Farralon islands 27 miles west of SF golden gate
bridge
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The Devils Teeth by Susan Casey
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How long do they live? Unknown. (But probably at
least thirty years, considering that white sharks
dont mature until theyre over ten years
old) Where do they mate, or when, or how often,
or even how? There are clues to the sex lives of
great white sharks, but no facts.The females
return only every other year, often with fresh,
deep bites around their heads. Are these wounds
related to mating? Do the females spend their off
years giving birth in warmer waters? For that
matter, how many great whites are there in the
oceans? All of this is a complete mystery.
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Objectives of the second half of the course

• Learn how animals, plants, and bacteria work.
• Understanding of relationship between organism
  function and physical principles
• Linkages between biochemistry/cell biology and
  whole organism function/ecology

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In the second half will discuss the basic
functional needs of organisms

• What is an animal animal diversity
• circulation and gas exchange
• nutrition
• control of internal environment
• chemical signaling
• reproduction
• nervous systems
• sensory and motor mechanisms

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This section introduces overall themes we will
come back to

• 1) Organisms have similar functional needs
• 2) Organisms must obey physical laws
• 3) Understanding how an organism works involves
  consideration of biochemistry, cell biology,
  physiology, ecology and evolution

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1. Organisms have similar functional needs
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bacterium
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Sea anemone
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(No Transcript)
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Example Size Does Matter (scaling effects)
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What is it like for a mayfly to hatch out of a
stream?
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E. coli swimming in water -- is like a human
swimming in hot asphalt
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How do insects cling to vertical surfaces?
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Example scaling of skeletons

• Is it possible to have 12 foot tall humans?
• Have to consider scaling effects

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What happens if you double thelinear dimension
of an animal?
tissue
skeleton
Cross sectional area pr2 Mass increases to the
third power of the linear dimension
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To avoid weaker skeletons on large animals, the
skeleton size increases disproportionately
Not This
This
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The relationship between skeleton size and body
mass for a variety of mammals
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The relationship between skeleton size and body
mass for a variety of mammals
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A mouse-sized elephant would have a skeleton
around 5 times heavier than a mouse
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3) To understand how the functional needs of
organisms are met, we need to integrate
information about

• Biochemistry
• Cell biology
• Physiology
• Evolution and Ecology

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Collagen

• most abundant protein of mammals
• skin, bone, tendon, cartilage, and teeth
• Great tensile strength
• 3 helical polypeptides nearly 1000 residues long
• repeated (...glycine-x-x-glycine-x-x) amino acid
  sequence
• Often Glycine-proline-hydroxyproline

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Structure of collagen
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What happens when there is faulty collagen Scurvy

• Jacques Cartier 1536 exploration of the Saint
  Lawrence River
• Some did lose all their strength, and could not
  stand on their feet.. Others also had all their
  skins spotted with spots of blood of a purple
  colour then did it ascend up to their ankles,
  knees, thighs, shoulders, arms, and necks. Their
  mouths became stinking, their gums so rotten,
  that all the flesh did fall off, even to the
  roots of the teeth, which did also almost all
  fall out.

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Why did this happen?

• Primates and guinea pigs cannot synthesize
  ascorbate (Vitamin C)
• Ascorbate is vital for the enzymatic conversion
  of proline (pro) to hydroxyproline (hyp)
• In scurvy patients, collagen has an amino acid
  sequence of gly-X-pro rather than gly-X-hyp

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Why does the improper amino acid sequence have
deleterious effects?

• Collagen of scurvy patients has a low melting
  temperature
• Melting temp 24 C for gly-X-pro in scurvy
  patients compared with 58 C for gly-X-hyp in
  normal people

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The pompeii worm Alvinella pompejana
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What about animals living at high temperatures?

• The pompeii worm lives on undersea volcanoes at
  temperatures reported to be as high as 80C
  making it the hottest living metazoan
  (multicellular animal) known.
• This is well above the melting temperature for
  normal collagen -- efforts are underway to
  determine the biochemical basis for high
  temperature collagen in these worms.

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Summary

• 1) Organisms have similar functional needs, but
  have developed diverse ways of meeting them
• 2) Organisms must obey physical laws
• 3) Understanding how an organism works involves
  consideration of biochemistry, cell biology,
  physiology, ecology and evolution