Lecture outline for the zoology unit
Introduction to animal form & function and regulation of TB (ch. 40 & Concept 42.4)
This first reading assignment reviews 5 major principles re living organisms:
Physical laws & the environment constrain the size & shape of organisms.
Form & function are correlated at all levels of organization.
Chemical energy in food is used to sustain form & function.
Many animals (& other organisms) regulate their internal environments within relatively narrow limits.
Regulation of TB (thermoregulation) contributes to homeostasis & involves anatomy, physiology, & behavior. ………………………………………………………………………………………………………
zoology: the branch of biology dealing with the study of animals
word of the day: Homeotic gene: a gene that controls the development of particular segments or regions of the body; it defines a region or position.
Concept 40.1: Organization of animal bodies
see homework assignment
Tissues form organs.
1. Please learn the organ systems found in animals & their major functions, as shown on Table 40.1 (I will not lecture about these).
2. How are organs formed, & what determines their location & function?
b. Hox genes: clusters of homeotic genes that occur in animals, but not in plants.
B. The bodies of animals contain lots of water! Body fluids are separated into compartments, as shown on fig. 40.7. (I will not lecture about these) (you are not responsible for the Fick equation)
intracellular fluid = where most of the water is
extracellular fluid = plasma + interstitial fluid
fluids & solutes move among compartments via osmosis, pressure gradients, passive diffusion, & active transport
40.2: Form & function are correlated at all levels.
The relationship between surface area & volume (the SA/V ratio): volume increases much faster than SA.
Fig. 3.1: A pair of cubes. Each edge of the cube on the right is three times as long as an edge of the one on the left. The cube on the right has nine times the surface and no less than twenty-seven times the volume of the one on the left.
(Vogel S. 1988. Life’s devices: the physical world of animals and plants. Princeton: Princeton University Press)
1. Does this relationship explain why most cells are small?
Volume increases much quicker then surface area… Cells are limited to 50 and 100 micrometers in size.. Reflects the rate of diffusion.
1um - .05 sec
100 um – 5.0 sec
1 cm – 14 hours
Extensive surface area is important for functions such as absorption, gas exchange, & communication. How do cells with these functions increase surface area without increasing size? (hint: see fig. 40.10) But by developing extension--- Increase surface area without increasing volume
Why do complex animals require organ systems?
40.3: homeostasis is essential for survival!
homeostasis can be controlled in 2 ways: regulating or conforming (note: some organisms have mixed strategies: they might regulate certain variables & allow others to conform to the environment). Conforming can result in energy savings.
Homeostasis… Living is work – Regulators – Conformers Conformers are able to save energy by allowing (body temp , PH) To fluctuate.
Feedback is essential to maintaining homeostasis.
negative and positive feedback loops (fig. 40.12, 40.13, 40.14) are both important, but most homeostatic mechanisms rely on negative feedback. Negative feedback loop - Examination of a furnace in a house. Control center – Maintains a constant temprature by counteracting the current situation.
High temp: damages plasma membranes, and proteins.,
The key components of feedback loops are
sensor (or receptor)
How do negative and...
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