water synthesized as a byproduct of cellular respiration.
ex. for animals living in the desert
an inescapable compromise between traits.
ex. as egg size increases, clutch size decreases = trade-off between egg size and egg number
a phenotypic change in an individual in response to short-term changes in the environment.
a group of similar cells that function as a unit.
cells that are loosely arranged in a liquid, jellylike, or solid extracellular matrix.
loose connective tissue
contains an array of fibrous proteins in a soft matrix and serves as apacking material between organs or padding under the skin
cartilage & bone (matrix)
have a firmer extracellular matrix.
they provide structural support for the vertebrate body
a connective tissue that has cells surrounded by a liquid extracellular matrix called plasma
consists of neurons and several types of supporting cells. they deliver electrochemical signals.
skeletal muscle tissue
consists of the long cells called muscle fibers which are packed with long protein filaments that move by sliding past each other.
cardiac muscle tissue
makes up the walls of the heart.
Each cardiac muscle cell branches and makes direct, end-to-end physical and electrical contact with other cardiac muscle cells.
smooth muscle tissue
cells are tapered at each end and form a muscle tissue that lines the walls of the digestive tract and walls of the blood vessels.
responsible for involuntary movements such as the passage of food
epithelial tissues (epithelia)
covers the outside of the body
lines the surfaces organs
epithelial tissue polarity or sidedness
apical side: faces away from other tissues and toward the environment
basolateral side: faces the interior of the animal and is connected to other tissues
ex. in your windpipe, the apical side secretes mucus and is covered with cilia. the basolateral side doesn't have either abilities or function
interior space of hollow organs
consists of groups of tissues and organs that work together to perform one of more functions
the overall rate of energy consumption by an individual.
measured in terms of oxygen consumption in units of mL of O2 consumed per hour.
basal metabolic rate (BMR)
the rate at which an animal consumes oxygen while at rest, with an empty stomach.
surface area/volume relationships
as an organism's size increases, its metabolic rate must decrease, of the surface area available for exchange of materials would fail to keep up with the metabolic demands generated by the enzymes in the organism.
small animals can "live fast" because they have enough surface area to support rapid metabolism
increasing surface area: gills
gills consist of sheetlike structures called lamellae. these sheets of epithelial cells provide this organ with an extremely high surface area relative to its volume.
increasing surface area: villi
villi are extensive folding that look like tubelike projections observed in portions of the digestive tract where nutrients diffuse into the body.
increasing surface area: capillaries
a highly branched network of small, thin-walled blood vessels.
the array of relatively stable chemical and physical conditions in an animal's cells, tissues, and organs.
in a fish whose body temperature is typically -1.9 degrees C. The fish isn't regulating its body temp. to match that of seawater.
instead, its body temperature remains constant simply because it conforms to the temp. of its surroundings.
based on mechanisms that adjust the internal state.
ex. panting or shivering
a normal or target value for the controlled variable
ex. animals have a set point for blood pH, blood oxygen concentration, nutrient availability
in mammals, the set point for body temp. is between 35 and 39 degrees C.
a structure that senses some aspect of the external or internal environment.
a component that evaluates the incoming sensory information and "decides" whether a response is necessary to achieve homeostasis.
any structure that helps restore the desired internal condition
effectors reduce or oppose the change in internal conditions
temp. regulation: conduction
the direct transfer of heat between 2 physical bodies that are in contact with each other.
temp. regulation: convection
heat exchange between a solid and a liquid or gas.
ex. the heat loss that occurs when wind blows on your skin
temp. regulation: radiation
the transfer of heat between 2 bodies that are not in direct physical contact
major source of radiant energy is the Sun
temp. regulation: evaporation
the phase change that occurs when liquid water becomes a gas.
leads only to heat loss
the control of body temperature
controls body temperature
signals from the posterior hypothalamus might induce shivering
an integrator in the anterior hypothalamus sends signals that initiate sweating or panting
endotherm (inner heat)
produces adequate heat to warm its own tissues
ectotherm (outer heat)
relies on heat gained from the environment
homeotherm (alike heat)
keep their body temperature constant
humans are endothermic homeotherms
heterotherms (different heat)
allow their body temperature to rise or fall depending on environmental conditions
Why are endotherms better at generating heat than ectotherms?
endotherms have high basal metabolic rates, and feathers or fur
also have adipose tissue - a connective tissue whose cells store fats. When the fat molecules are oxidized by the mitochondria, only heat and no ATP is produced.
common in animals
two adjacent fluids flow through adjacent pipes in opposite directions.
this arrangement makes it possible for a gradient to be maintained between the two pipes.