Exam 1 Flashcards
integrated study of how biological systems work
- integrates knowledge from all levels of biological organization
animal physiology
what are the 2 main questions physiologists seek out about how an animal works?
- What is the mechanism by which a function is accomplished?
- What is the origin of that function?
components of living organisms that enable animals to perform
mechanism
the evolutionary processes that conspired to produce a mechanism.
- the evolutionary significance of mechanisms
origin
_______ ______ is a key process of evolutionary origin
natural selection
increases in frequency of genes that produce phenotypes that raise the likelihood that animals will survive and reproduce
- occurs within populations. it is not an individual level phenomenon. Individuals don’t evolve, populations do
natural selection
traits (or physiological mechanisms) that are products of evolution by natural selection
adaptation
What are the modes of natural selection?
- directional selection
- stabilizing selection
- disruptive selection
most cells of an organism are exposed to the _______ environment not the _______ environment
- internal
- external
the _____ environment may be permitted to change when the _____ environment changes, or it may be kept constant
- internal
- external
what are the levels of biological organization?
- atom
- molecule
- organelles
- cells
- tissues
- organ
- organ system
- organism
how an animal moves in that environment
biomechanics
______ also depends on how they move and the different capabilities they have
morphology
what are 2 parameters associated with a bell curve?
- mean
- standard deviation (SD)
what mode of natural selection is: certain groups of phenotypes that are favored by natural selection OR a group of phenotypes that are disfavored by natural selection.
- shift in mean phenotype
- thought to be quite common
mean: change variance: no change
directional selection
which mode of selection is: stabilizing the phenotype around the current mean
- mean is maintained, variance decreased
- is fairly common
stabilizing selection
which mode of natural selection is: variance is often increased, and the mean may or may not change
- is rare
disruptive selection
who was the first to recognize the stability of conditions humans maintain in their blood.
Claude Bernard
What was Claude Bernard’s principal area of study?
blood glucose levels
introduced an important term referring to “internal constancy”
Walter Cannon
homeostasis
- internal stability
- the existence of regulatory mechanisms to make adjustments to maintain stability
- internal body temperature of 26-28ºC
What were Walter Cannon’s 3 postulates?
- Nervous system preserves the normal conditioning of the body.
- The tonic activity if a system can be modulated up & down.
- There are factors that have opposing effects=antagonist controls
What area of the brain is there a thermostat that activates cooling/warming mechanisms
Hypothalamus
Negative Feedback
Positive Feedback
snowball effect. Not bringing anything back to homeostasis at all. (Ex. oxytocin signaling during mammalian birth of offspring)
Physiological timescales
timeframes in which physiology changes
- Acute (immediate)
- Chronic (long-term, after a few days or weeks of exposure)
changes in individuals
Evolutionary
changes in populations
Phenotypic plasticity
the ability of an individual animal to express two or more genetically controlled phenotypes
isometric growth
-proportions remain constant
- each dimension is scaled up or down by same amount
allometric growth
-changes in body proportions with changes in body size
- different rates of growth of different parts
- the proportions vary depending on the rates at which SA, volume, & other physical parameters change with size
Scaling
the structural & functional consequences of changes in size of otherwise similar organisms
For geometrically similar objects:
- SA is proportional to LENGTH^2
- V is proportional to LENGTH^3
- SA is proportional to V^2/3
SA:V ratio
Smaller objects have larger SA relative to their volume than larger objects of the same shape (i.e. they have larger SA:V ratios)
- benefit & curse-larger surface area relative to volume means quicker diffusion
- good for something like O2 absorption, bad for water loss
How does the endocrine system communicate?
By endocrine cells into the bloodstream
- much slower but response is prolonged more
Neuron
basic unit (specialized cells) of the nervous system
Nervous system
neurons & their support cells (glial cells)
Sensory (afferent) neurons
conduct signals from receptors to the CNS
Interneurons (associations neurons)
are confined to the CNS