what are adaptations?
heritable traits that allow individuals to survive and reproduce in a certain environment better than individuals that lack those traits.
When does natural selection occur?
whatever individuals with certain alleles leave more offspring than do individuals with different alleles. Because of this difference in reproductive success, the frequency of the selected alleles increases from one generation to the next
Besides natural selection, how else does evolution occur?
through random changes in allele frequencies called genetic drift, through gene flow and through constant introduction ofnew alleles by mutation
true or false, natural selection, mutation, genetic drift and gene flow increase the ability of organisms to survive and reproduce in a particular environment.
false, natural selection is the only mechanism that does so
how are adaptations limited?
by which alleles are present in a popuolation and by the nature of the traits that already exist-because all adaptations are derived from preexisting traits.
what is acclimatization or acclimation?
short-term, reversavle physiological and biochemical changes that are revfersible responses to environmental fluctuations
what is the difference between acclimatization and adaptation?
acclimatization is a phenotypic change in an individual in response to short-term changes in the environment whereas adaptation refers only to a genetic change in a population in response to natural selection exerted by the environment
true of false: structure-function correlations are limited to the molecular and cellular level
false, they also exist at the levels of tissues, organs and systems
define the term multicellularr
bodies contain distinct types of cells that are specialized for different functions
as an individual develops, the embryonic tissues give rise to 4 adult tissue types: what are they?
1) connective tissue 2) nervouse tissue 3) muscle tissue 4) epithelial tissue
what is connective tissue
consists of cells that are loosely arranged in a liquid, jellylike, or solid extracellular matrix, which is secreted by the connective tissue cells themselves.
true or false: all connective tissue secretes the same kind of extracellular matrix
false: each type of connective tissue secretes a distinct type of extracellular matrix
what is loose connective tissue
contains an array of fibrous proteins in a soft matrix and serves as a packiing material between organs or padding under the skin
what is cartilage and bone?
connective tissue types that provide structural support fo the vertebrate body or protective enclosures for the brain and other components of the nervous system
what is blood?
connective tissue that has cells surrounded by a liquid extracellular matrix called plasma; blood functions in the transport of materials throughout the body
what is nervous tissue?
consists of nerve cells a.k.a. neurons, and several types of supporting cells
what do a neuron's projections do?
deliver electrochemical signals, which are produced by changes in the permeability of the neuron's plasma membrane to ions
what do support cells do?
regulate ion concentrations in the space surrounding neurons, supply neurons with nutrients, or serve as scaffolding or support for neurons
each cardiac muscle cell branches and makes direct, end-to-end physical and electrical contact with other cardiac muscle cells. What do these connections help do?
transmit signals from one cardiac muscle cell to another during a heartbeat
what are smooth muscle cells?
cells that are tapered at each end and form a muscle tissue that lilnes the walls of the digestive tract and the walls of blood vessels
true or false: the same types of neurons that control the contraction of smoothe muscle cells also control the contraction of striated muscle cells
false: different types of neurons control the contraction of smooth muscle cells vs striated muscle cells
what type of muscle is responsible for involuntary movements such as the passage of food down the digestive tract or the dilation of arteries near the skin in hot weather?
where is epithelium found?
it covers the outside of the body, lines the surfaces of organs, and forms glands
how do epithelia act as gatekeepers?
regulate the transfer of heat between the interior and exterior of structures, as well as the transfer of water, nutrients and other substances
what is the structure of epithelial cells like?
typically forms layers of closely packed cells; in many cases adjacent epithelial cells are joined by structures that hold them tightly together, such as tight junctions and desmosomes
true or false: epithelial tissue has a polarity or sidedness in only some parts of the body
false: has polarity or sidedness no matter where it is found in the body
what is the apical side of epithelial tissue?
faces away from other tissues and toward the environment
what is the basolateral side of epithelial tissue?
faces the interior of the animal and is connected to other tissue
describe how epithelial tissue lining the a lumen such as your small intestine functions
the apical surface is folded into fingerlike projections that are studded with membrane proteins that take up glucose and other nutrients from the food you have digested. The basolateral membrane of these epithelial cells contain different proteins from those on the apical side. on the basolateral surface, glucose and other nutrients are then transported across the plasma membrane to nearby blood vells, which distribute them throughout the body
what is a 'system'?
consists of groups of tissues and organs that work together to perform one or more functions
true or false: the organism as a whole is greater than the sum of its parts. Why or why not?
true because the structure and function of each component of the body are integrated with other components and because each level of organization is integrated with other levels of organization
at what levels do biologists study animal anatomy and physiology?
molecullar, cellular, tissue, organ and system levels
true or false: many of the challenges posed by increasing size are based on the asymmetrical relationship between surface area and volume
true or false as a cell gents larger, its surface area increases much faster than its volume
false: as a cell gets larger, its volume increases much faster than its surface area does
how many dimensions does are have compared to volume
area has two dimensions whereas volume has three
how is metabolic rate oftem measured?
in terms of oxygen consumption, and is typically reported in units of mL of O2 consumed per hour
how do biologists report metabolic rate to furnish a more useful way to compare metabolic rates in different species?
divide metabolic rate by overall mass and report a mass-specific metabolic rte in unmits of mL O2/gram/hour.
what is basal metabolic rate (BMR)?
the rate at which an animal consumes oxygen while at rest, with an empty stomach, under normal temperature and moisture conditions. This is the accepted convention to report an indivudal metabolic rate since it varies dramatically with its activity
true or false: large animals have a higher BMR than smaller animals?
false: small animals have a much higher BMR than do large animals
why must the mass-specific metabolic rate decrease as an organism/s size increases?
if it didn't decrease, the surface area available for exchange of materials would fail to keep up with the metabolic demands generated by the enzymes in the organism
what are gills?
in aquatic animals, gills are organs that allow the exchange of gases and dissolved substances between the animal's blood and the surrounding water
what are the sheetlike structures that gills consist of?
lamellae-sheets of epithelial cells that provide the organ with an extremely high surface area relative to its volume allowing hases to diffuse across the gills rapidly enough to keep up with the growth in the volume of the developing fish.
how must a structure be shaped if the function of a cell or tissue depends on diffusion?
in a way that increases its surface area relative to its volume
what are effective ways for structures to have a high surface area/volume ratio?
flattening (eg. Laminae of fish gills), folding (eg. Villi in small intestine) and branching (eg. Capillaries)
what is homeostasis?
the array of relatively stable chemical and physical conditions in an animal's cells, tissues, and organs (all about constancy). Although internal conditions may vary as environment changes, chemical and physical states are kept within a tolerable range.
what is the difference between conformational homeostasis and regulatory homeostasis?
conformational homeostasis is when a property matches surrounding properties (eg. A fish that has the same internal temperature as the surrounding water) regulatory homeostasis is a mechanism that brings the property to a managable rate when external properties begin to exceed or fall below a tolerable state (eg. a dog pants when its hot to cool down and shivers when its cold to warm up)
what is a set point?
a normal or target value for a controlled variable (i.e. temperature, blood pressure, blood pH and blood glucose
what three general components are homeostatic systems based on?
a sensor, an integrator and an effector
what role does the sensor play in a homeostatic system?
is a structure that senses some aspect of the external or internal environment
what role does the integrator play in a homeostatic sensor?
the integrator is a component that evaluates the incoming sensory information and "decides" whether a response is necessary to achieve homeostasis
what role does the effector play in a homeostatic system?
an effector is any structure that helps restore the desired in condititernal
homeostatic systems are based on negative feedback. What happens when negative feedback occurs?
effectors reduce or oppose the change in internal conditions
in what four ways do animals exchange heat with the environment?
conduction, convection, radiation and evaporation
what is conduction?
the direct transfer of heat between two physical bodies that are in contact with each other.
what does the rate at which conduction occur depend on?
the surface area of transfer, the steepness of the temperature difference between the two bodies, and how well each body conducts heat
T of F: a person loses heat much faster when air is at a temperature of 15 degC than when that person is immersed in water at the same temperature
false, water conducts heat much faster than air does so body temperature drops much quicker in water at 15 degC than when air is the same temperature
what is convection?
a special kind of conduction, during convection, heat is exchange between a solid and a liquid or gas (rather than between two solids as it is in conduction)
what is the name of the receptors in your brain region responsible for responding to changes in blood temperature?
true or false all animals are always either ectothermic or endothermic?
false many animals are partially both
what are heterotherms
organisms that allow their body temperature to rise or fall depending on environmental conditions
which of the following describes humans the best?
A) ectothermic heterotherms
b) endothermic heterotherms
c) ectothermic homotherms
d) endothermic homotherms
e) partially ectothermic and endothermic homotherms
d) endothermic homeotherms - humans produce their own heat metabolically and maintain a constant body temperature
what is torpor?
a condition in which organisms reduce their metabolic rate and allow body temperature to drop
T of F: ectotherms only gain their heat directly by basking in the sumlight or lying on warm rocks or soil
false: ecotherms generate some heat as a by-product of metabolism
why is it meaningful that mitochondrial density and mitochondrial enzyme activity are 3-4 times higher in endotherms' cells than in cells of ectotherms of similar size?
endotherms have a higher basal metabolic rate which is demonstrated by this comparison because most reactions that generate ATP and heat occur in the mitochondria
what is brown adipose tissue?
a specialized type of adipose tissue that features a high density of mitochondria as well as stored fats. When fat molecules are oxidized by the mitochondria, no ATP is produced, all chemical energy stored in the fats is released as heat producing almost 10 times as much heat as other tissues
what are countercurrent exchangers?
an arrangement in which two adjacent fluids flow through adjacent pipes in opposite directions to conserve heat
why are their no endotherms smaller than a shrew or a hummingbird?
surface/area volume relationship: small organisms lose heat much faster than large objects do, so it is difficult for small endotherms to stay warm without expending prohibitive amounts of energy
what is the mathematical relationship between surface area (SA) and volume (V)?
A) SA = V^2
b) SA = V^3
c) SA = V^2/3
d) SA = 2V
c) SA = V^2/3
T/F the speed of diiffusing particles as they ove through the cell is slower in larger cells
false: its just that it takes much longer for the particles to diffuse throughout thegreater volume of the cell
which of the following are structures in the mammalian digestive tract that allow for efficient distribution of nutrients to the rest of the body?
which of the following statements about diffusion across a cell membrane is true?
A) the surface area of the membrane determines how many molecules can enter a cell at once
b) it take longer for particles to diffuse throughout large cells in comparison to small cells because of the larger surface area of the cell membrane
c) small cells and large cells have similar abilities to balance the rate of oxygen uptake with the rate of oxygen consumption
d) the speed of diffusing particles is slower in large cells than in small cells
what relationship between surface area an volume must organisms achieve to ensure efficient delivery of nutrients?
A) maximize surface area and minimize volume
b) keep surface area and volume equal
c) minimize surface area and maximize volume
d) none of these is correct
a) maximize surface area and minimize volume
which term describes a mechanism by which the internal conditions of an organism are kept at set values without regard to external conditions?
A) conformational homeostasis
c) negative feedback
d) regulatory homeostasis
d) regulatory homeostasis
which of the following actions is not a function of epithelium?
A) allows the internal environment to alter its conditions to match those of the external environment
b) regulates the excretion of waste
c) controls the exchange of nutrients between the internal and external environments
d) creates an internal environment that is different from the external environment
a) allows the internal environment to alter its conditions to match those of the external environment
T/F organisms must maintain homeostasis because optimal enzyme activity is achieved within a very narrow range of conditions
how do biologists measure an animal's metabolic rate?
A) by taking its temperature
b) by measuring how rapidly it uses oxygen
c) by measuring how rapidly it uses glucose
d) by measuring how rapidly it produces wastes
how is the structure of a connective tissue most closely correlated with its function?
A) the density of cells in the tissue correlates with the tissue's function
b) the surface area of the tissue correlates with the tissue's function
c) the origin of the tissue (from endoderm, mesoderm or ectoderm) correlates with the tissue's function
d) the nature of the extracellular matrix correlates with the tissue's function.
as an animal gets larger, which of the following occurs?
A) its surface area grows more rapidly than its volume
b) its volume grows more rapidly than its surface area
c) its volume and surface area increase in perfect proportion to each other
d) its volume increases but its total surface area decreases
which of the following best describes the set point in a homeostatic system?
A) the cells that collect and transmit information about the state of the system
b) the cells that receive information about the state of the system and that direct changes to the system
c) the various componnets that produce appropriate changes in the system
d) the target or "normal" value of the parameter in questions
what does it mean to say that an animal is a heterothermic endotherm?
A) its body temperature can vary, but it produces heat from its own tissues
b) its body temperature varies because it gains most of its heat from sources outside its body
c) its body temperature does not vary because it produces heat from its own tissues
d) its body temperature does not vary, even though it gains most of its heat from sources outside its body.
which of the following is an advantage that ectotherms have over endotherms of the same size?
A) they require much less food
b) they can save energy in cold weather by hibernating (entering torpor for long periods)
c) they can remain active in cold wesather or at nighttime-when temperatures cool
d) they have higher metabolic rates and grow much more quickoly
When do biologists typically use the phrase form and function?
as a framework for understanding how physiological processes critically depend on structure, from cells to tissues to organs to the whole body.
Chum salmon (Oncorhynchus keta) are born in freshwater environments and then migrate to the sea. Near the end of their lives, they return to the freshwater stream where they were born to spawn. In freshwater, water constantly diffuses into the body and ions are lost from the body. In salt water, body water diffuses out of the body and excess ions are gained from the water. A salmon's gills have special cells to pump salt in or out of the body to maintain homeostasis. In response to the salmon's moves between freshwater and salt water, some cells in the gills are produced and others are destroyed. These changes made in the cells of the gills during the lifetime of an individual salmon are an example of which of the following?
Your professor announces he has discovered a new species of bird that feeds mostly on worms and soft-bodied insects picked up from the ground and off of leaves. Based on this information, what shape of beak would you predict for this bird?
A) wide and curved like a scoop
b) long and narrow like tweezer
c) short and pointy like a needle
d) broad and flat like a shovel
b) long and narrow like tweezers
If you are looking through a microscope at a slide of animal tissue and see a single layer of closely packed cells, you are likely looking at a sample taken from which of the following?
A) the cardiac muscle of the heart
b) a long bone
c) a tendon
d) the inside of the cheek
e) a biceps during contraction
d) the inside of the cheek
Which of the following structural features of epithelial tissues are related to the function of these cells?
A) they have polarity
b) they have a long life span
c) low rates of mitosis and cytokinesis
d) the cells are loosely packed
a) they have polarity
Which of the following is a true statement about body size and physiology?
A) the amount of food and oxygen an animal requires and the amount of heat and waste it produces is inversely porportional to its mass
b) small and large animals face different physiological challenges because an animal's body mass increases cubically while its surface area increases as a squared function
c) the rate at which an animal uses nutrients and produces waste products is independent of its volume
d) the wastes produced by an animal double as its volume doubles and tripe as its surface area triple.
A researcher is setting up an experiment to measure basal metabolic rate in prairie voles (Microtus ochrogaster - a small rodent). Which of the following would be the best set of conditions for the voles immediately before and during the measurement?
A) House the animals in a cage with plenty of food and water to avoid stress; conduct measurements in a warmer room than the room where housed.
b) House the animals in a cage with no food for a few hours before measurement; conduct measurements in a room the same temperature as the room where housed.
c) House the animals in a cage with no food for a few hours before measurement; conduct measurements in a colder room than the room where housed, and exercise the voles.
d) House the animals in a cage with plenty of food and water to avoid stress; conduct measurements in a room the same temperature as the room where housed.
If an organism was discovered that had no epithelial tissues, it would require adaptations to maintain homeostasis in which of the following areas?
A) the organism would require adaptations that would prevent water loss from the body in a terrestrial environment
b) the organism would require adaptation in its circulatory system for transport of blood
c) the organism would rquire adaptaqtions in its nervous system for sensing external stimuli
d) the organism would rquire adaptations in its skeleton for structure
e) the organism would require adaptations in its muscular system for movement
You discover a new species of bacteria that grows in aquatic environments with high salt levels. While studying these bacteria, you note that their internal environment is similar to the salt concentrations in their surroundings. You also discover that the internal salt concentrations of the bacteria change as the salt concentration in their environment changes. The new species can tolerate small changes in this way, but dies from large changes because it has no mechanism for altering its own internal salt levels. What type of homeostatic mechanism is this species using to regulate its internal salt levels?
e) all of the above
A woman standing and watching the stars on a cool, calm night will lose most of her body heat by which mechanism?
e) radiation and convection only
There are advantages and disadvantages to adaptations. Animals that are endothermic are likely to be at a disadvantage in which of the following environments?
A) very cold environments
b) very hot environemtns
c) environments with a constant food source
d) environments with variable and limited food sources