CH. 7 Animal Adaptations Flashcards
_____ imposes a fundamental constraint on the evolution of animals.
size
All animals have two fundamental limitations:
- operating within gravitational limitations
2. getting enough fuel (oxygen) for their size
All aerobic animals must maintain ____ concentrations in their tissues high enough to fuel their metabolism. If this cannot be accomplished, death is inevitable.
oxygen
Surface area to volume
volume increases faster than surface area
Respiratory organs are measured with a _____ function.
squared
Larger animals have disproportionately _____ respiration abilities.
smaller
Metabolism SHOULD scale with body mass^___
2/3
Metabolism is utlimately powered by
respiratory organs (length^2)
Kleibers Law states that
metabolism scales with body mass^3/4
Metabolic scaling
the scaling of metabolic rate may have more to do with the interaction of shape and size than just size alone.
Fractal pattern
an object that maintains similar patterns at increasingly small scales.
The scaling of metabolism is not easily predicted but is likely a function of
size and shape
LSD and the Elephant
- Can LSD induce “musth?”
- gave LSD to Tusko the elephant
- after 5 mins, the elephant trumpeted, fell over, defecated, and died
- dose was DRASTICALLY miscalculated
- was 1000x too high
What was the problem with the LSD and the elephant experiment?
the dose was 1,000x too high; the scaling of metabolism with size was not considered prior to dosage calculation
The newest predictions of how metabolism scales with body size includes a
curvilinear fit
If the curvilinear fit is true, metabolic scaling may directly determine:
maximum animal size
If an animal has a metabolism any more than where the slope >1 it means they are using _____ energy just to be that large.
excess
Changes in size are produced throughout
development
embryogenesis
differentiation before hatching/birth
growth
increase in size
development
transformation of structure
Ontogeny
the growth and development of an organism (throughout an organism’s entire life cycle)
Scaling
the changes in size and shape across ontogeny
______ is the origination and development of an organism
ontogeny
Isometric scaling
when one variable (body measurement) increases in equal proportions with another measure of body size
Allometry
when one body measure does not increase at the same rate as another measure of body size
When a feature scales differently than a 1:1 ratio, we call it
allometric
Morphogenesis
the unfolding of form and structure
Heterochrony
change in the timing of development and growth of traits
Paedomorphism
the retention of juvenile traits by adults
Two major outcomes of heterochrony:
- paedomorphism
- paramorphosis
Paedomorphism results from
- derived trait has reduced growth rate compared to ancestral trait
- development ends earlier in derived trait compared to the ancestral trait
- development starts later in derived trait compared to the ancestral trait
Paramorphosis
the development of entirely new shapes, beyond typical adult form
Some species can be _____ or _____.
paedomorphic; metamorphose
Facultative paedomorphs
being able to retain larval morphology while being sexually mature
Obligate paedomorphs
don’t have the ability to get rid of their juvenile traits
Timing of metamorphosis is affected by
physiological and environmental factors
Physiological and environmental factors that affect timing of metamorphis include:
- pond or stream drying
- population density
- food availability
- predator abundance
- increasing temperature
- hormones
- tissues sensitivity to hormones
When an animal is confronted with an environmental shift it has two options:
-conform or regulate
conformers
unable to maintain consistent internal conditions
regulators
use a variety of biochemical, physiological, morphological, and behavioral mechanisms to regulate their internal environment
Conformers have internal body solute concentrations based on the ____ _____ that they reside in.
environmental conditions
For conformers to be successful:
internal processes must be capable of functioning across a wide array of environmental conditions; if systems cannot function at a particular level, the animal may shut down activity until conditions become suitable
In contrast to conformers, regulators often spend ____ _____ to maintain a narrow range of internal conditions.
considerable energy
Critical minimum temperature
a minimum temperature for a given species in which unorganized locomotion is observed, suggesting imminent death
CTmax
a maximum temperature for a given species in which unorganized locomotion is observed, suggesting imminent death
Thermal tolerance range
the range of temperatures in which an animal typically operates
Topt
the body temperature that produces maximum performance
In all muscles: rate of force generation is ______ related to muscle temperature
directly
Homeostasis
our body maintains a constant internal environment even when in varying environmental conditions
Homeostasis is controlled by _____ _____ mechanisms.
negative feedback
Negative feedback
occurs when a specific condition changes beyond the normal range and changes are initiated in order to return the system to the normal range
Set point
mean body temperature under ideal conditions
Three components for a set point to function
- receptor
- integrator
- effector
receptor
measures the internal environment, transfers information to the integrator
integrator
receives information and compares it to the set point
effector
causes a change in the internal environment
Temperature
single most important factor limiting the distribution of ectothermic animals
Temperature profoundly affects animal
structure and function
It is important to regulate
body temperature
Rates of water loss (increase/decrease) with temperature
increase
cellular environment
viscosity of cytoplasm, permeability of membranes, muscle contraction speed, etc.
biochemical reaction rates
gas exchange, metabolism, digestion, etc.
Whole-animal function
growth, alertness, speed, escape
Activity temperature range
normal range of temperatures in which activity occurs
mean activity temperature
the mean of all temperatures of active animals
Preferred temperature
the temperature selected by individuals in a thermal gradient when all external influences have been removed
operative temperature
equilibrium temperature for an animal in a particular environment
voluntary minimum
the lowest temperature tolerated voluntarily in the lab
voluntary maximum
the highest temperature tolerated voluntarily in the lab
critical thermal minimum
the low temperature that produces cold narcosis thus preventing locomotion and escape
critical thermal maximum
the high temperature at which locomotion becomes uncoordinated and the animal loses its ability to escape conditions that will lead to its death
Poikilothermy
wide variation in Tb in response to environmental temperature
Homeothermy
constant Tb even with greater environmental temperature fluctuations
Ectothermy
condition in which the external environment is the source of heat
Endothermy
condition in which heat is produced metabolically (internal)
Heliothermy
gaining heat by basking in sun
thigmothermy
gaining heat by conduction (ex. lying on warm rock not exposed to sun)
Acclimation
functional compensation to experimentally induced environmental change
Thermoregulation
maintenance of a relatively constant Tb even though environmental temperatures vary; heat exchange with the environment
Thermal conformity
Tb varies directly with environmental temperature; there is no attempt to thermoregulate
Poikilotherms
animals that exhibit a wide range of body temperatures
homeotherms
body temperature is constant or nearly constant
Ectothermy
the process of maintaining body temperatures through external sources
Endothermy
the process of maintaining body temperatures through internal sources
Most ectotherms control body temperature over _____ ____
narrow ranges
Behavioral thermoregulation is im portant for
ectotherms
Physiological control of body temperature
- muscular shivering
- cardiovascular control
Aestivation
occurs in some species in dry seasons
Hibernation
occurs in cold seasons; usually due to cold temps more than food limitations
_______ take on characteristics of ectotherms and endotherms
heterotherms
Example of heterotherms
butterflies: butterfly wings are used for fflight, but the large size is due to their use as thermoregulatory panels
Torpor
dropping of body temperature to ambient temperature to ambient temperature levels
Hibernation
long-term, seasonal torpor
Some animals use ______ means for thermal balance
physiological
ex. camels are weird
Freeze resistance=
supercooling
supercooling
animals don’t freeze event when Tb is at freezing temperature; ice crystals are prevented from forming in cells
Freeze tolerance
ability to survive freezing; animals freeze and thaw without ill effect
_______ prevent ice crystals form forming inside the cell.
ccryoprotectants
Poikilotherms regulate their body temperature primarily through
behavioral mechanisms
Bergmann’s rule
tendency for an increasing body size with increasing latitude (decreasing environmental temperature)
What groups follow the inverse of bergmann’s rule?
snakes and lizards
Energy Balance Equation describes
all the ways that an animal may gain thermal energy
The energy balance equation: Heat energy gained=
Qabs + M +/- R +/- C +/- LE +/- G
Qabs
solar radiation
Qabs=?
S x A x Vf(s) x a
S=
intensity of solar radiation
A=
surface area of animal
Vf(s)=
view factor=proportion of surface receiving radiation
a=
absorptivity to solar radiation
M=?
metabolic heat
R=?
radiative heat exchange
C=?
convective heat exchange (occurs between animal and fluid (air/water) around it
LE
evaporative cooling
G=?
conduction
Both ____ and ____ factors affect thermal balance and thermoregulation
physiological and biotic
Thermoneutral zone
range of environmental temperatures within which metabolic rates are minimal
Endothermy and Ectothermy involve
trade-offs
Endothermy advantage
can remain a given body temperature regardless of environmental temperature
endothermy disadvantage
require much higher energy input just to minimally survive
Ectothermy advantage
can sustain life with minimal energy needs
Ectothermy disadvantage
body temperature is dependent upon available heat sources outside the animal’s control
Heterotherm
a species that can function both as a homeotherm and poikilotherm depending on environment and need
gills
fan-like organs with high surface area to volume; where gas exchange occurs
amphibians do not have ____ or a ____
ribs; diaphragm
Without a diaphragm, _____ and ______ must be used to ventilate the lungs in reptiles.
ribs; muscles
Animals maintain a balance between water uptake and _____
loss
water balance
the loss of water for life processes coupled with the need for constant water uptake
Animals that inhabit arid regions avoid water loss by:
reducing their activity
