animal form and function pt 2 Flashcards
what are regulators?
uses mechanisms of homeostasis to moderate internal change in the face of external fluctuations ex. endotherms thermoregulate
what are conformers?
allows some conditions within its body to vary with cetiain external changes ex. spider crabs osmoconform
What is osmoregulation?
management of the bodies water content and solute composition
What is osmosis
diffusion of water across a selectively permeable membrane
what is molarity?
moles of solute/ volume of water
what is osmolarity?
osmoles of solute particcles/ volume
what is osmolality?
osmoles of solute/ KG
what is isosmotic with medium?
body fluids = same osmotic pressure as medium
most marine invertebrates
what is hyperosmotic?
osmotic concentration higher than medium
freshwater organisms
what is hypoosmotic?
osmotic concentration lower than medium
marine bony fish
What is an osmoconformer?
animal that does not actively adjust its internal osmolarity because is it isoosmotic with its environment
Osmoregulator is what?
animal whose body fluid has a different osmolarity than that of the environment
anima
Osmoregulator
animals that live in a hypoosmotic environment must do what?
discharge exces water
Osmoregulator
animals that live in a hyperosmotic environment must do what?
take in water
Osmoregulator
how do Osmoregulator
control internal osmolarity?
expenditure of energy
Fresh water animals:
what are they?
osmoregulators
Fresh water animals:
how do they gain and lose water?
how do they regain
what do they excrete?
gain: osmosis and food
lose: salts by diffusion and in urin
regain: salts in food and by active uptake from surroundings
excrete large amounts of dilute urine
Water balance in the ocean:
most marine invertebrates are what?
osmoconformers
cnform to osmolarity of ocean but regulate internal ionic composition
Water balance in the ocean:
most marine vertebrates are what?
osmoregulator
lose water by osmosis
gain water and salt in food and drinking seawater
dispose of salt by active transport out of gills and in urine
produce small amounts of urine
Animals that move between fresh and salt water:
what are stenohaline?
what are euryhaline?
stenohaline: organisms that cannot tolerate substantial changes in external osmolarity
euryhaline: organisms that CAN tolerate substantial changes in external osmolarity
water balance and waste disposal depends on what?
epithelia
animals regulate solute content of body fluid that bathes their cells
water balance and waste disposal:
transport epithelium is what?
layers of specialized cells that regulate solute movements
most important feature: ability to move specific solutes in controlled amounts in particular directions
cells joined by tight junctions
in most animals they are arranged into tubular networks with extensive surface area
what is an example of transport epithelia in osmoregulators?
nasal glands of marine birds remove excess sodium chloride from blood
What is anhydrobiosis?
“life without water” ability to survive in a dormant state when an organism’s habitat dries up
ex. tardigrade
what three elements make up the homeostatic system?
sensor- perceives change
integrator- control center
effector- brings about response
what are two types of control circits?
negative feedback- change counteracted (most common)
positive feedback- change augmented
Alterations in homeostasis:
regulated change is what?
in internal environment essential to normal body functions (ex. hormone shift in puberty)
Alterations in homeostasis:
circadian rhythm is what?
physiological cycle of 24 hr in animals and plants
persists even in absense of external cues
Alterations in homeostasis:
acclimation
physiological adjustment to a change in a single environmental factor
protein change in response to temp
Alterations in homeostasis:
acclimatization
physiological adjustment to change in complex environmental factors
ex. change in altitude and O2 level
Thermoregulation is what? what are the four physical processes that account for heat loss or gain?
regulation of body temp
1 conduction
2 convection
3 radiation
4 evaporation
What is evaporative cooling?
the property of a liquid whereby the surface becomes cooler during evaporation, owing to a loss of highly kinetic molecules to the gaseous state
Thermal stratagies:
what are the two main ones?
tolerance : body temp is allowed to vary with ambient temperature
regulation: body temp does not vary with ambient temp
based on the source of thermal energy what are the two classes?
Ectotherm - environment determines body temp
Endotherm - animal generates internal heat to maintain body temp
Based on stability of body temp there are two classes what are they?
poikilotherm- variable body temp
Homeotherm- stable body temp
What is the cost of ectothermy?
inability to physiologically regulate body temo
restricted in geographical regions with appropriare ambient temp
very limited time of high activity/energy bursts
not as good at avoiding predators thought “flight”
What are the benifits of Ectothermy?
lower metabolic rates
slower, low energy appoach to life
require less food and water
can function with much smaller body masses than endotherms
What are the costs to endothermy?
considerable metabolic cost; high rate
requires consumption of large quantities of food and water
very susceptible to dehydration in hot/dry climates
only small amount of energy budgeted for growth and reproduction
small body size is rare due to surface area constraints on heat loss
benefits of endothermy?
can sustain long period of intense activity
enzymes function optimally in narrow range of body temps
can be active at times of day or year that are too cold for ectotherms
not limited to geographic areas
more likely to survive weather fluctuations
Circulatory adaptations
vasodilation is what? results in what? triggered by what?
increase in diameter of superficial blood vessels
results in elevated blood flow in the skin
triggered by nerve signals that relax the muscles of the vessel wall
in endotherms, usually wams skin increasing the transfer of body heat to cool environment
Circulatory adaptations
vasoconstriction is what?
decrease in the diameter of superficial vessels
reduces blood flow and heat transfer
what are countercurrent heat exchangers?
special arrangement of blood vessels
they facilitate heat transfer from arteries to veins
help trap heat in the body core
important in reducing heat loss in many endotherms
Examples of cooling by evaporation heat loss?
behavioural responses?
sweating, panting, mucus secretion
change in posture, or moving about environment
how do animals balance heat loss and gain?
insulation
adaptation to circulatory system (vaso dilation/constriction)
countercurrent heat exchange
evaporative cooling
behaviour
how to animals balance heat gain and loss?
adjust metabolic heat production
producing heat
high basal metabolic rate
-production of large amounts of metabolic heat that replaces the flow of heat to the environment
shivering thermogenesis
- increase muscle activity–> increase heat production
nonshivering thermogenesis
- increase metabolic rate due to hormones
- increase mitochondrial activity –> produce heat instead of ATP
- brown fat specialized for rapid heat production
temporary/ seasonal endothermy
body size- large helps retain metabolic heat
What is the feedback mechanism in thermoregulation in mammals
hypothalamus functions as thermostat
sensory cells signal to it when temp changes
it will activate or inhibit different mechanisms
Bioenergetics of animals:
animals are heterotrophs that harvest chemical energy from food
ingested energy will be used for what?
work
stored
excreted
released as heat
Bioenergetics of animals:
heat production in animals is what?
usless for doing work
useful for maintaining body temp
What is the metabolic rate?
amount of energy an animal uses in a unit time; sum of all the energy requiring biochemical reactions occuring over a given time interval
How can metabolic rate be mesured?
by monitoring an animals rate of heat loss
O2 consumption
CO2 production
What is Basal Metabolic Rate (BMR)
stable rate of energy metabolism measured in mammals and birds under conditions of minimum environmental and physiological stress
What is standard metabolic rate (SMB)
a measure that is similar to BMR but used for an animal with varying body temp that is maintained at a selected body temp
in other words:
an animals resting and fasting metabolism at a given body temp
Adjustment to changing temp and seasonal changes: acclimation and acclimatization?
production of stress induced proteins ex. heat shock proteins
Adjustment to changing temp and seasonal changes: acclimation and acclimatization
in birds?
adjusting the amount of insulation
varying the capacity for metabolic heat production
Adjustment to changing temp and seasonal changes: acclimation and acclimatization
in ectotherms
adjustment at the cellular level
production of cryoprotectants
What is Torpor?
physiological state in which activity is low and metabolism decreases
What is hibernation?
long-term torpor evolved as an adaptation to wonter cold and food scarcity
ex. bears squirrels
What is estivation?
summer torpor also characterized by slow metabolism and inactivity
ex. amphibians, fish interrbrates
who does daily torpor?
hummingbirds
