Lecture 6 Flashcards
how have animal structures evolved? what is an example?
-as a result of functional outcomes
-ex: beavers flat and wide tail (used for locomotion, communication, body temp regulation)
what is anatomy?
-the biological form of an animal
-features that have evolved to enable survival in an animal’s environment
what is physiology?
-the biological functions an organism performs
what does the comparative study of animals reveal?
-that form and function are closely correlated
what is the basic principle?
-there is adaptation through natural selection
-variation meets environment
what does the size and shape of an animals forms affect?
-the way an animal interacts with its environment
-how it exchanges energy + materials with its surroundings (larger SA = higher exchange)
what does the genome determine?
-an animals body plan
what ability depends on an animals shape, size, and environment?
-ability to perform certain actions
what does evolutionary convergence reflect?
-different species adaptations to a similar environmental challenge
what happens when body dimensions increase?
-when body dimensions increase, stronger skeletons are needed to provide support
-muscles also must increase for locomotion purposes
what is an example of how physical laws impose constraints on animal size + shape
-waters dense property will limit the shape of fast swimmers
-tapered on both ends and body will be sleek to overcome drag during swimming
how does exchange occur within an animals cells?
-substances that have dissolved in an aqueous medium will diffuse and be transported across the membrane
what substances are typically exchanged?
-nutrients
-wastes
-gases
what correlates with the rate of exchange?
-membrane surface area
what correlates with the amount of material exchanged?
-cell volume
what allows multicellular organization to work?
-every cell having access to a suitable aqueous environment (inside + outside the body)
-body plans must meet this requirement
what are ideal body plans for multicellular organization?
-sac body plan
-body walls are only 2 cells thick to facilitate diffusion
-flat body plan
-most cells are exposed to intestinal fluid
how do highly complex organisms with high cell numbers increase their outer SA to volume ratio?
-branching + foldings
in vertebrates, what is between cells? what does this allow for?
-interstitial fluid
-allows for movement of material in and out of cells
-exchange with the circulatory fluid
what is biggest challenge for physiological systems?
-being able to survive in a variable environment
what helps animals survive in a variable environment?
-a complex body plan
-helps to keep the internal environment of the animal stable
for what type of animals specifically does a complex body plan help? why?
-land animals
-environments typically are more variable
what are most animals composed of?
-specialized cells organized into groups called tissues that deliver different functions
what do different tissue types create? what together will these create?
-create organs
-organs will together create organ systems
what do organ systems entail?
-higher level of organization and coordination
what differs between different tissue types?
-their structures
-structures are suited to their desired function
what two structures/organs are lined with similar tissue types?
-lungs
-blood vessels
what are the four main tissue catergories?
-epithelial
-connective
-muscle
-nervous
what is the purpose of epithelial tissue?
-covers the outside of the body and lines organs and cavities within the body
-functions as a barrier
how are cells jointed within epithelial tissue?
-closely
what is the purpose of connective tissue?
-mainly binds and supports other tissues
what does connective tissue contain?
-sparsely packed cells scattered throughout an extracellular matrix
-fibroblasts
-macrophages
what do fibroblasts secrete?
-fibre proteins
what do macrophages do?
-engulf foreign particles and cell debris through phagocytosis
what does the extracellular matrix contain?
-fibres in a liquid jelly like or solid foundation/base
what are the types of muscle tissue?
-cardiac muscle
-skeletal muscle/striated muscle
-smooth muscle
what is the purpose of cardiac muscle?
-contraction of the heart
what is the purpose of skeletal muscle?
-attached to bones and is responsible for voluntary movement
what is the purpose of smooth muscle?
-lines internal organs and is responsible for involuntary movement
what is the purpose of nervous tissue?
-senses stimuli and transmits signals throughout the body
what does nervous tissue contain?
-neurons/nerve cells
-glial cells/glia
what is the function of neurons/nerve cells?
-transmit impulses
what is the function of glial cells/glia
-nourish, insulate, and replenish neurons
what systems do control and coordination within the body depend on?
-endocrine system
-nervous system
what does the endocrine system do?
-transmits chemical signals called hormones to receptive/target cells throughout the body via the blood
how many regions of the body can a hormone affect?
-one or more
what is an example of a fast acting hormone?
-epinephrine (adrenaline)
what is an example of a slow acting hormone?
-thyroid stimulating hormone
can slow acting hormones have long lasting effects?
-YES
what does the nervous system do?
-transmits information between specific locations
what does the information conveyed within the nervous system depend on?
-the signals pathway
what does the information conveyed within the nervous system not depend on?
-the type of signal
is nerve signal (electrochemical) transmission fast or slow?
-very fast
what types of cells can nerve impulses be received by?
-neurons
-muscle cells
-endocrine cells
how do animals manage their internal environment?
-by regulating or conforming to the external environment?
how does a regulator deal with external environment changes?
-use internal control mechanisms to keep internal conditions stable despite environmental changes
how does a conformer deal with external environment changes?
-allows its internal condition to vary relatively equally with the environmental changes
-may also seek other environments
is it more energetically expensive to be a regulator or a conformer?
-regulator
is it possible for animals to be both a regulator and a conformer depending on the nature of the conditon?
-YES
-no animal is truly one or the other, they just tend to be more of one than the other
what is an example of an animal that is a regulator for one condition and a conformer for another condition?
-largemouth bass
-thermoconformer
-ionregulator
what is homeostatis?
-maintenance of internal balance (keeping a constant internal environment)
in humans what conditions are maintained at a constant level by homeostatsis?
-body temp
-blood pH
-glucose []
what serves as the stimulus for homeostatsis?
-flucutuations above or below the internal set point
what detects stimuli? what does this trigger?
-sensor or receptor in the body
-triggers a response to bring the condition back to the set point
how does negative feedback act? what stops the system?
-acts to reverse/return a condition to its normal range/set point
-a buildup of the end product will shut the system off
how do most homeostatic control systems function?
-by negative feedback
how does positive feedback act? what is an example of where positive feedback acts?
-acts to drive certain processes (not usually contributing to homeostasis)
-escalate a trend
-ex: childbirth
what are some important aspects of set points and normal ranges?
-may change with age
-can show cyclic patterns (circadian rhythm)
what is often confused with adaptation?
-acclimation
-acclimization
what is acclimation?
-remodeling in response to a single environmental factor
-simple
what is acclimization?
-the process of the adjustment of homeostasis to complex changes in the external environment
-complex
what is thermoregulation?
-the process by which animals maintain an internal temperature within a normal range
what are many processes dependant on?
-temperature
-higher temp may increase efficiency or vice versa
what are endothermic animals? what are examples?
-animals that generate heat by metabolism (internal body processes)
-can withstand large fluctuations in their external environment
-ex: birds + mammals
what are ectothermic animals? what are examples?
-animals that gain heat from external sources
-may produce some heat in metabolism but not an influential amount
-ex: most invertebrates, fishes, amphibians, and reptiles
generally which type of animals will need to consume less food? why?
-ectotherms
-don’t need to fuel metabolic process as much as endotherms
-endothermy is more energetically expensive (need a higher consumption)
what is the key difference between endotherms and ectotherms?
-endotherms are active at a greater range of external temperatures
-ectotherms can tolerate greater variation in internal temperatures
how is the body temperature of a pokilotherm?
-varies with its environment
how is the body temperature of a homeotherm?
-relatively constant
-not perfectly correlated with endothermy and ectothermy
how is the body temperature of a heterotherm?
-maintains different temperatures within different regions of its body
-ex: shark
how do organisms exchange heat?
-through 4 processes
-conduction
-convection
-radiation
-evaporation
what does heat regulation in mammals typically involve?
-the integumentary system (skin, hair, nails)
what is radiation?
-emission of electromagnetic waves (sunlight)
what is conduction?
-direct transfer of heat through contact
what is convection?
-transfer of heat through movement of air or liquid
what is evaporation?
-removal of heat by evaporation
what are the 5 adaptations that help animals thermoregulate?
-insulation
-circulatory adaptations
-cooling by evaporative heat loss
-behavioural responses
-adjusting metabolic heat production
what are examples of things that insulate animals? what do they do exactly?
-skin, feathers, fur, and blubber
-reduce heat flow between an animal and its environment
what are animals changing with circulatory adaptations?
-how much blood flow is near the bodies surface
what are the 3 methods of circulatory adaptations?
-vasodilation
-vasoconstriction
-countercurrent exchange
what is vasodilation?
-blood flow near the surface increases, facilitating heat loss to the environment (endotherm common)
-superficial blood vessels widen
what is vasoconstriction?
-blood flow near the surface decreases, lowering the amount of heat loss to the environment
-superficial blood vessels shrink
what is countercurrent exchange?
-heat is transferred between fluids flowing in opposite directions (veins + arteries)
-artery temp is warmer than vein temp
-important mechanism for reducing heat loss
-can be temporarily shut down
what allows for an animal to perform countercurrent exchange? what types of animals perform this?
-the arrangement of their blood vessels
-ex: marine mammals and birds
what is evaporative cooling? what increases the cooling affect?
-heat loss through the evaporation of water in sweat
-sweating cools an animal down
-panting can increase this effect
what are behavioural responses to control body temp?
-seeking areas of ideal temperature
-terrestrial invertebrates have postures that minimize or maximize the absorption of solar heat (sun)
how is metabolic heat production increased typically?
-muscle activity (moving or shivering)
what do some mammals poses that help produce heat?
-brown adipose tissue (specialized to produce heat)
-produce heat by cells through proteins called thermogenin
how do the thermogenin proteins produce heat?
-cause mitochondria to produce heat rather than ATP
what is the process of heat production called?
-thermogenesis
what region of the brain controls thermoregulation?
-hypothalamus
-triggers heat loss or heat generating mechanisms
-sensor/receptor
what type of environment do physiological systems operate in? what must be maintained here?
-fluid environment
-water and solute concentrations must be maintained within fairly narrow limits (maintaining osmolarity)
what is osmoregulation?
-regulates solute concentrations and balances the loss and gain of water
what are the common solutes that must be maintained within the body?
-sodium
-calcium
what adaptations do freshwater animals have to help with osmoregulation?
-adaptations that reduce water uptake and conserve solutes
what kind of environments do desert and marine animals live in? how do they adapt?
-desiccating environments that can deplete body water
-conserve water in fish
-eliminate excess salt in marine birds + fish
what does excretion get rid of?
-nitrogenous metabolites
-waste products
what is osmoregulation largely based on?
-controlled movement of solutes between internal fluids and the external environment
what do cells require in terms of osmoregulation?
-a balance between osmotic gain and the loss of water in order to regulate chemical composition of body fluids
what is osmolarity? what does it determine? what are its units?
-the solute concentration of a solution
-determines the movement of water across a selectively permeable membrane
-units are osmoles of solute per litre of solution (Osm/L)
what does it mean for 2 solutions to be isosmotic?
-the movement of water is equal in both directions
-no net movement of water
what is a hypoosmotic solution?
-more dilute solution
what is a hyperosmotic solution?
-less dilute solution
what will happen if 2 solutions differ in osmolarity?
-the net flow of water will be from the hypoosmotic solution to the hyperosmotic solution
what are osmoconformers? what animals are they?
-isosmotic with their surroundings and do not regulate their osmolarity
-ex: only some marine animals (most marine invertebrates)
what are osmoregulators? what animals are they?
-expend energy to control water uptake in a hypoosmotic environment and water loss in a hyperosmotic environment
-minimizes the change in internal osmolarity
-ex: freshwater and some marine animals (marine vertebrates and some invertebrates)
what determines solute concentrations?
-the activity of protein transporters that move ions and solutes in and out of the cell
what type of animals differ in their ability to tolerate changes in external environments?
-aquatic animals
what does it mean for an animal to be stenohaline?
-cannot tolerate substantial changes in external osmolarity
-makes up most animals
what does it mean for an animal to be euryhaline?
-can survive large fluctuations in external osmolarity
does an animals osmotic strategy relate to their osmotic tolerance? what is an example?
-they do not relate
-ex: sockeye salmon is a euryhaline osmoregulator
how do terrestrial animals regulate water movement?
-through diet and excretion
what is known of the physiological mechanisms for water and ion balance in terms of their evolutionary history?
-they have been evolutionarily conserved
-meaning they are present in a majority of species (origin to present)
how do marine bony fishes perform osmoregulation?
-hypoosmotic to seawater (lose water by osmosis, gain salt by diffusion and from food)
-balance water loss by drinking seawater and excreting salts (through kidney and gills)
how do the gills of marine bony fishes excrete salts?
-actively transport Cl- out and passively allow Na+ to follow
how does the kidney of marine bony fishes excrete salts?
-excess calcium, magnesium, and sulfate excreted in small amounts of water
how do freshwater animals perform osmoregulation?
-take in water constantly by osmosis (hypoosmotic environment)
-lose salt by diffusion
-maintain water balance by excreting large amounts of dilute urine
-salt loss is replaced by food intake + gill uptake
what is a diadromous fish? what are some examples?
-live part in salt and part in freshwater
-ex: salmon + eels
what is required for a fish to be diadromous? what is this process called?
-reorganization of osmoregulatory systems
-smoltification (complex series of changes)
what is smoltification and when does it occur?
-complex series of physiological changes
-prepares fish to enter seawater after the final step of acclimization
how are desert animals able to save so much water?
-simple anatomical features (body coverings)
-behaviours (nocturnal lifestyle)
how are land animals able to lose and gain water?
-lose water through urine, feces, skin, etc
-gain water through drinking, eating moist foods, and metabolic water
what is transport epithelia?
-specialized epithelial cells that regulate solute movement
-essential component of osmotic regulation and metabolic waste disposal
how is transport epithelia arranged?
-complex tubular networks (increase SA)
what is an example of transport epithelia?
-the salt glands of marine birds
-remove excess sodium chloride from the blood
