Transcript 174-16-Winter_2_7-Ja.. - Department of Biology

1
Introduction to
Biology 174
2
"Ecological and Evolutionary Physiology"
(BIOL 174) Winter 2016
Professor:
Dr. Theodore Garland, Jr.
Department of Biology
Office:
2366 Spieth Hall
Phone 827-3524 - better for
long questions
[email protected]
Office Hours: Tuesday 8:30-9:30 and
Wednesday 10:30-11:30 A.M.
in 2366 Spieth, or by appt.
3
Lecture: Tuesday and Thursday
2:10 - 3:30 A.M. in 2200 Spieth Hall
Lectures will be posted on the
"Blackboard" website ilearn.ucr.edu
after the lecture is finished.
Discussion: All are on Wed.
12:10-1:00, 1:10-2:00, 4:10-5:00, 5:10-6:00 PM
Syllabus: Both Lecture and Discussion
are posted on the course website.
T.A. will go over with you.
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Teaching Assistant:
Mr. Jarren Kay
Ph.D. candidate
Department of Biology
[email protected]
Office Hours:
Monday 10:30-11:30 PM
Thursday 11-12 PM
in 2378 Spieth Hall, or by appointment
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"Ecological and Evolutionary Physiology"
(BIOL 174) Winter 2014
Catalog Description: Interactions between
organisms and their environments, emphasizing
coadaptation of physiological, morphological,
and behavioral phenotypes.
Topics include: allometry and scaling,
metabolism and locomotion, heat and water
exchange, evolution of endothermy, artificial
selection experiments, and phylogenetically
based statistical methods.
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Some other Relevant Courses at UCR:
"Animal Physiology"
(BIOL 175)
"Comparative Biomechanics"
(BIOL 176)
"Hormones and Behavior"
(BIOL 178)
"Animal Behavior"
(BIOL 160)
"Functional Anatomy of the Vertebrates"
(BIOL 161 A, B)
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Required Text: Readings posted on the
"Blackboard" website ilearn.ucr.edu
Don’t get behind on the reading!
Exams will take some material
directly from the reading, even if we
have not discussed it in class!
A copy of the first exam from a previous
year is posted on the Blackboard
website. Warning:
Material covered will not be identical !!!
Format may differ !!!
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Grading
Item
Points
% of Total
-------------------------------------------------------------------------------------------------Pre-Course Survey (5 Jan)
20
8.9
Midterm Exam 1 (28 Jan)
40
17.8
Midterm Exam 2 (25 Feb)
40
17.8
Final Exam 3 (14 Mar)
60
26.7
Attendance
10
4.4
Participation
10
4.4
3 Quizzes (6 Jan, 3 Feb, 2 Mar)
15 (5 pts each)
6.7
Paper Critique (20 Jan)
10
4.4
Heritability Exercise (9 Mar)
20
8.9
Discussion Section
-------------------------------------------------------------------------------------------------
Total Points
225
100
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How grades are determined (of total points):
> 90% = A
> 80% = B
> 70% = C
+ or - may also be used
> 60% = D
< 60% = F
Scale may be moved down ("curved"), depending
on distribution of total points at end of course.
I cannot tell you in advance if this will happen
or by how much.
10
Regrades: only within one week of when you
get it back. We will regrade the whole thing,
and points on ANY question may go up or
down.
Missed assignments: no make-ups are
allowed, except for ...
Valid excuses, absences: tell us when it
happens, or before. Do not wait until the end
of the quarter! For medical absences, we
need a note from your healthcare provider.
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Lecture 2:
Historical Development of Ecological
and Evolutionary
Physiology
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Some highlights,
not a thorough account ...
C. Ladd Prosser:
a founder of comparative physiology
Edited 1950 volume, in which
he outlined a broad
agenda for comparative physiology:
Prosser, C. L., ed. 1950. Comparative animal
physiology. W. B. Saunders Co.,
Philadelphia. ix + 888 pp.
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14
Five Big Goals:
1. Simply to describe how different kinds of
animals meet their needs.
= cataloging biological diversity
"Biodiversity" often = how many species
But perhaps equally important is how
variable are those species, morphologically,
physiologically, behaviorally? In other
words, functional diversity.
Recently, some have criticized this as "stamp
collecting" and said that we must now move
beyond that phase of simple description.
15
2. Use physiological information to reconstruct
phylogenetic relationships of organisms.
In principle, we could use physiological
information just like we use morphological
information or DNA sequences.
In practice, has rarely been done, for 4 reasons:
a. physiology doesn't leave many fossil cues
b. it can't be measured on museum specimens
c. it is difficult to measure as compared with
morphology or DNA sequences
d. more likely to be adaptive than DNA, so subject
to parallel and convergent evolution, which
confuses phylogenetic reconstruction.
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3. To elucidate how physiology mediates
interactions between organisms and their
environments.
= physiological ecology or
ecological physiology
17
4. To identify "model systems" for studying
particular physiological functions.
= comparative physiology
Examples:
a. squid giant axons for nerve transmission
b. rattlesnake tail shaker muscles because whole
animal can be put in an NMR to measure
in vivo changes in metabolites
Conley, K. E., and S. L. Lindstedt. 1996. Rattlesnake tail-shaking:
minimal cost per twitch in striated muscle. Nature 383:71-73.
c. ectothermic poikilotherms in general to study
effects of temperature on physiology
d. lizards to study effects of fever
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5. Vague ... but indicates that "kind of animal"
can be used as a sort of "experimental
variable."
Scientists routinely conduct experiments to test
hypotheses.
Nature conducts "natural experiments,"
e.g., putting animals in a desert,
and we can use the results of these past
experiments to understand how evolution occurs.
19
What's in a name?
Noun conveys the main focus of the subdiscipline,
adjective conveys the particular flavor.
Comparative physiology tends to focus on
physiology and how it varies among different
organisms.
Biomedical physiologists may see
"comparative" as anything other than
human beings or "the rat."
Physiological ecology focuses on ecology, and
how physiology affects interactions between
organisms and their environment.
20
Physiological ecology has always had an
evolutionary component.
Calow, P., ed. 1987. Evolutionary physiological ecology. Cambridge
University Press, Cambridge. 239 pp., back cover:
"Physiological ecology is concerned with the way that
physiological traits fit organisms for the ecological
circumstances in which they live, so there is always, by
definition, an implicit evolutionary component to it."
Bennett, A. F., and R. B. Huey. 1990. Studying the evolution of
physiological performance. Pages 251-284 in D. J. Futuyma and
J. Antonovics, eds. Oxford surveys in evolutionary biology. Vol. 7.
Oxford Univ. Press, Oxford., p. 251:
"The field of physiological ecology ... is ...
fundamentally evolutionary to the extent that it
considers how organisms came to be the way they are
and how they might change in the future."
21
Although Comparative Physiology and
Physiological Ecology have always had
evolutionary components, they were often an
afterthought.
Typical mode of operation: make whatever
physiological measurement they specialized in
on some new, exotic or unusual organism ...
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23
… then tack on a paragraph about the adaptive
(evolutionary) significance of whatever they
found.
24
For Example:
compare a temperate and an
arctic-inhabiting bird.
Any difference that was found would be attributed
to the past effects of natural selecting
(i.e., an evolutionary adaptation).
Possibilities of phylogenetic inheritance or
random genetic drift were not considered.
Often, a priori hypotheses were not tested.
Or, if they were tested, it was not with the rigor
that would be found in evolutionary biology
(e.g., only two species might be compared).
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These sorts of inferences have been
criticized as "just-so stories."
"Just So Stories"
by Rudyard Kipling
Originally published 1902
http://en.wikipedia.org/wiki/Just_So_Stories
First published in 1902,
these are origin stories,
fantastic accounts of how
various phenomena came
about.
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HOW THE ELEPHANT GOT ITS TRUNK
HOW THE WHALE GOT HIS THROAT
HOW THE CAMEL GOT HIS HUMP
HOW THE RHINOCEROS GOT HIS SKIN
HOW THE LEOPARD GOT HIS SPOTS
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So, the standards of evidence and interpretation
used by evolutionary biologists were not being
employed by most physiologists who wished to
say something about the evolution of their
favorite physiological system or organism.
In short, many physiologists were practicing
evolutionary biology without a license.
29
Evolutionary physiology is a new subdiscipline
that incorporates much of Prosser's (1950) five
objectives, but with more rigorous evolutionary
tools and definitions.
This course will emphasize the methods of
ecological and evolutionary physiology and
their conceptual background, rather than
providing lots of empirical facts concerning how
different kinds of organisms make their living or
have evolved physiologically.
Also, I will show lots of examples. Try to
remember the general point of these examples.
And we will need some definitions …
30
For example, the word "adaptation" has several
meanings, with two being common in biology:
1. the genetic, evolutionary process of traits that
change across generations because of
natural selection and consequent changes
in gene frequencies
(a property of populations);
Bennett, A. F. 1997. Adaptation and the evolution of physiological characters.
Pages 3-16 in W. H. Dantzler, ed. Handbook of physiology.
Section 13: comparative physiology. Vol. I. Oxford Univ. Press, New York.
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2. within-individual changes in response to
environmental perturbations
= phenotypic plasticity (these changes
are not passed on to offspring)
a. Acclimatization = in the field
b. Acclimation = in the lab
Often these changes are reversible (phenotypic
flexibility)
May occur at any point in the lifecycle, but those
occurring early, during "critical periods," may be
less reversible ...
Piersma, T., and J. A. van Gils. 2011. The flexible phenotype:
a body-centred integration of ecology, physiology, and behaviour.
Oxford Univ. Press, Oxford, U.K. ix + 238 pp.
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Example with Laboratory House Mice:
Mohammed A. Al-kahtani. 2003.
Ph.D. in Zoology at the Univ. of Wisconsin - Madison.
"Evolutionary and Phenotypic Plasticity of Mammalian
Kidney: Using the Laboratory House Mouse as a Model."
Currently faculty at
King Faisal University,
Saudi Arabia.
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Three Goals:
Determine how mice "adapt" ontogenetically to
reduced water availability.
Create a "model" for studying kidney function.
Create a "model" for studying desert rodents or
other desert mammals.
Eventually apply to "conservation physiology"
in the context of captive breeding progams for
endangered gazelle.
34
Two groups, starting at weaning (21 days of age)
FW-J = Free Water-Juveniles
WR-J = Water Restricted-Juveniles
35
Method for Restricting Water
Daily water consumption in both juvenile groups
Fig. 3-4
FW-J
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Values are means +
standard deviations
WR-J
10.0
9.5
9.0
8.5
8.0
7.5
Water cons. (ml/d)
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
20
25
30
35
40
45
50
55
Age (days)
60
65
70
75
80
85
90
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Food intake significantly decreased in water-restricted group.
WR-J
Fig. 3-5
FW-J
6.0
5.5
Food Consumption (g/d)
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
20
25
30
35
40
45
50
55
Age (days)
60
65
70
75
80
85
90
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Water restriction stunted the growth of water-restricted group.
WR-J
Fig. 3-2
FW-J
40
38
36
34
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Body Mass, (g)
30
28
26
24
22
20
18
16
14
12
10
20
25
30
35
40
45
50
55
Age (days)
60
65
70
75
80
85
90
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Are such changes reversible,
or do they carry over as the
animals continue to age?
40
Reversal
Experiment
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Control
Groups
"Water-Restricted, then Free Water" group drank copiously when reversed to free
water and remained significantly higher than Free Water group.
Water-Retsricted, then Free Water
Water-Restricted
Fig. 4-5
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Free Water, then Water-Restricted
Free Water
16
15
14
13
12
Water Cons. (ml/d)
11
10
9
8
7
6
5
4
3
2
1
0
20
30
40
50
60
70
80
90
Age (days)
100
110
120
130
140
150
160
Food intake is intimately linked with water consumption in house mice.
Water-Restricted, then Free Water
Water-Restricted
Fig. 4-7
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Free Water, then Water-Restricted
Free Water
5.5
5.0
Food Intake. (g/d)
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
20
30
40
50
60
70
80
90
Age (day)
100
110
120
130
140
150
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The effects of early-life water restriction are not completely reversible.
Water-Restricted, then Free Water
Water-Restricted
Fig. 4-2
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Free Water, then Water-Restricted
Free Water
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Body Mass, g
35
30
25
20
15
10
20
30
40
50
60
70
80
90
Age (days)
100
110
120
130
140
150
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The kidneys became larger (relative to body mass) in the
water-restricted juvenile group.
WR-J
Fig. 3-7
FW-J
-0.10
Log10 Paired Kidney Mass, g
-0.15
-0.20
-0.25
-0.30
-0.35
Note that if you did not account for the
difference in body mass, you would
conclude that the kidneys of the waterrestricted group became smaller!
-0.40
-0.45
-0.50
1.10
1.15
1.20
1.25
1.30
1.35
1.40
Log10 Body Mass, g
1.45
1.50
1.55
1.60
1.65
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The urine was much more concentrated in the
water-restricted juvenile group.
Fig. 3-19
WR-J
FW-J
5500
4500
-1
Urine Osmolality (Mosm . Kg )
5000
n = 10
4000
n = 11
n = 16
3500
3000
n = 12
2500
2000
n = 11
n = 15
n = 15
1500
n = 12
1000
500
20
25
30
35
40
45
50
55
Age (days)
60
65
70
75
80
85
90
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The heart became smaller (relative to body mass) in the
water-restricted juvenile group.
Fig. 3-11
WR-J
FW-J
-0.60
-0.65
-0.70
Log10 Heart Mass, g
-0.75
-0.80
-0.85
-0.90
-0.95
-1.00
-1.05
-1.10
1.10
1.15
1.20
1.25
1.30
1.35
1.40
Log10 Body Mass, g
1.45
1.50
1.55
1.60
1.65
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What about trans-generational
effects?
• This would be a good topic for future research
• Any evidence for epigenetic inheritance?
• Epigenetic processes:
– changes caused by modification of gene
expression rather than alteration of the genetic
code itself
– heritable changes in gene expression that do not
involve changes to the underlying DNA sequence
• e.g., by DNA methylation
Stopped here 6 Jan. 2015
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The origin of modern
"Evolutionary Physiology"
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Modern evolutionary physiology arose in the late
1970s and early 1980s.
Three main contributing factors:
1. Debates concerning the metabolic and
thermoregulatory status of dinosaurs and
mammal-like reptiles. Were dinosaurs warm
blooded?
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2. attempts to integrate quantitative genetic
perspectives into evolutionary biology
and behavioral ecology:
a. focus on individual variation as raw
material for natural selection,
not just "noise"
b. attempts to estimate heritability of traits
c. attempts to measure selection acting
in nature
Bumpus, H. C. 1899. The elimination
of the unfit as illustrated by the
introduced sparrow, Passer domesticus.
Mar. Biol. Lab., Biol. Lect. (Woods
Hole, 1898), pp. 209-226.
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3. attempts to integrate phylogenetic perspectives
into comparative biology:
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Stopped here 8 Jan. 2013 & 9 Jan. 2014
Close
Relatives
Tend to
Resemble
Each Other
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Evolution from a Physiological
Perspective and vice versa:
recurring themes in ecological
and evolutionary physiology
1. How do Different Kinds of Organisms Work?
a. Discover general principles of organismal
function, such as homeostasis or the scaling
of metabolic rate with body mass.
b. Find exceptions to the rules, species that are
"outliers" from the general trend.
c. Determine whether there exist multiple
solutions to a given adaptive problem.
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Because all organisms on this planet are
descended from common ancestors - and
probably from a single common ancestor general biological principles are likely to
occur in a strongly hierarchical
(phylogenetic) pattern.
Related organisms tend to resemble each
other in terms of how they are built and how
they do things;
for example, use of DNA as a genetic
material, structure of eukaryotic cell
membranes, responses to changes in
ambient temperature by mammals.
56
Evolution from a Physiological
Perspective and vice versa:
recurring themes in ecological
and evolutionary physiology
1. How do Different Kinds of Organisms Work?
a. Discover general principles of organismal
function, such as homeostasis or the scaling
of metabolic rate with body mass.
b. Find exceptions to the rules, species that are
"outliers" from the general trend.
c. Determine whether there exist multiple
solutions to a given adaptive problem.
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c. Determine whether there exist multiple
solutions to a given adaptive problem.
What are some of the "solutions" that animals use
to live in hot, dry deserts?
Are these evolved differences or phenotypic
plasticity?
What about plants?
58
2. Extremes of Adaptation, "Model" Species, and
The August Krogh Principle
a. Identification of similarities among species
allows the possibility that certain species may
be able to serve as "model systems" for
studying basic physiological processes.
b. August Krogh noted that
for any physiological
principle there exists an
organism especially well
suited for its study
(e.g, giant axons of squid).
59
Squid can contract the muscles of
the mantle simultaneously, thus
forcing sea water through the
mantle aperture and causing the
body to move forward.
An important part of this system is
a big ganglion from which departs a
giant axon.
The axon sends signals to all
muscles involved in the process,
and is much thicker than any axon
of other animals.
Accordingly, it has been used in
many studies of nerve signalling,
e.g.:
Hodgkin A.L. & Huxley A.F. 1952.
Propagation of electrical signals along
giant nerve fibers. Proc. R. Soc. Lond.,
B Biol. Sci. 140:177-183.
Giant squid (Architeuthis) are enormous
molluscs from the deep sea. The maximal
length (from the dorsal fin to the end of a
tentacle) is estimated to be 13 m in females
and 10 m in males. These animals have a
highly sophisticated nervous system, highly
developed brains and excellent eyes.
60
c. Similarly, organisms living in extreme environments are especially likely to exhibit clear
examples of evolutionary adaptation, because
of the presumably intense past selection.
They can also serve to illustrate the range of
evolutionary possibilities.
But we must remember that the organisms
alive today -- and hence available for
physiological study -- are but a small fraction
of what has existed.
We have no guarantee that we can observe
the range of possibilities even among the
most extreme of living species.
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Example:
Dinosaurs,
such as
Spinosaurus
http://www.biology.ucr.edu/people/faculty/Garland/Spinosaurus_30_Theo_29_Sep_2004.jpg
62
Example: the largest terrestrial mammal ever
(Indricotherium [formerly Baluchitherium]) was much larger
than living elephants, mammoths or mastodons.
An extinct hornless rhinoceros that lived in the Oligocene epoch (3020 million years ago). Fossilized remains found in central Asia show
that it was over 5 m high, with a heavy giraffe-like body.
63
Giant birds (both flying and flightless) once
existed, giant dragonflies.
And then there were plesiosaurs, ichthyosaurs,
etc.
Many transitional forms are now extinct.
Environmental conditions differed as well, e.g.,
temperature and atmospheric oxygen and carbon
dioxide.
Environmental conditions differed as well, e.g.,
atmospheric oxygen.
http://geology.com/usgs/amber/oxygen-level-chart.gif
64
Environmental conditions differed as well, e.g.,
temperature & atmospheric carbon dioxide.
http://deforestation.geologist-1011.net/PhanerozoicCO2-Temperatures.png
65
66
Opthalmosaur
Pterosaur
Some extinct forms are rather
different from living organisms, or
seem sort of like "hybrid" models.
67
A recently-extinct
species that
demonstrated
convergent
evolution with
placental wolves.
68
Plate 8.2 The last living
Plate 9.1 Rear view of the
Tasmanian tiger, Hobart Zoo, 1933. last living Tasmanian tiger,
Hobart Zoo, 1933.
Died night of 7
September 1936
Stopped here 7 Jan. 2016
69
3. Are Species Differences in Physiology
Adaptive?
The neo-Darwinian synthesis, with its emphasis
on natural selection as the major driving force in
evolution, led to the view that virtually all features
of organisms are adaptive.
Comparative physiologists have routinely viewed
any differences among species as adaptations to
their different life styles.
And, of course, many examples clearly do
represent strong evidence for adaptation.
70
Nonetheless, not all features of organisms
represent adaptations to current environmental
conditions.
Some represent simple inheritance from
ancestors.
"Four legs may be optimal, but [tetrapods]
have them by conservative inheritance, not
selected design." (S. J. Gould, 1980, p. 44)
A similar statement could be made about insects
(6 legs) or spiders (8 legs).
Genetic variation for leg number is virtually absent
in extant populations, so natural selection cannot
change it. A sort of "phylogenetic constraint."
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"Darwin pointed out in The Origin of Species that
the sutures in the skull of young mammals
'have been advanced as a beautiful adaptation for
aiding parturition, and no doubt they facilitate, or
may be indispensable for this act;
72
"Darwin pointed out in The Origin of Species that
the sutures in the skull of young mammals
'have been advanced as a beautiful adaptation for
aiding parturition, and no doubt they facilitate, or
may be indispensable for this act; but as sutures
occur in the skulls of young birds and reptiles,
which have only to escape from a broken egg, we
may infer that this structure has arisen from the
laws of growth, and has been taken advantage of
in the parturition of the higher animals.'
73
Gould and Vrba (1982) have offered the term
exaptation to describe features that now enhance
fitness, but were not built by natural selection for
their current role." (Futuyma, 1986, p. 257)
74
4. Are Organisms Optimally Designed?
In addition to presuming that most features of
organisms are adaptations, a common perspective
in comparative physiology is to view organisms as
optimally designed,
i.e., more-or-less perfectly adapted in some sense.
"We do not think a functional explanation
complete until we can show that a structure
or movement is optimal (by some plausible
criterion) for the proposed function."
(Alexander, 1988, p. 237)
"Evolution by natural selection is a process
of optimization." (Alexander, 1996, p. 2)
75
This is a controversial view (more later in course),
and many workers have a very different
expectation about "how good" organisms are,
e.g.,
"Natural selection increases fitness but it
produces systems that function no better than
they must. It yields adequacy of adaptation
rather than perfection."
(Bartholomew, 1987, p. 14)
Natural selection involves relative fitness, not
absolute fitness.
If a tiger is chasing you, you only have to be able
to run faster than the guy next to you …
76
5. What is the Origin of Allometric Relationships?
Allometry = how and why properties of organisms
change in regular ways in relation to body size.
Scaling = essentially a synonymous term in
biology, but used in other ways in engineering,
image processing, computer science.
Example: does "smartness" vary with body size
or among evolutionary lineages?
77
Slope = 1.00
log-log axes
Largeer
Slope = 0.67
animals
have
relatively
smaller
brains.
78
log-log axes
Vertical
deviations
from "line
of best fit"
(residuals)
indicate
deviation
from
general
effect of
body size.
79
Extra
Slides
Follow
Add something on:
learning outcomes
the scientific method
levels of analysis
MPBF
proximate vs. ultimate causation
4 ways to study evolution:
CM
Biology of Natural Populations
Selection Experiments
Theoretical Models
Plasticity? Epigenetics?
https://www.msu.edu/.../Methods&Levels.
ppt from ZOL 313 May 14, 2008
80
4 Ways to Study Physiological Evolution
1. Phylogenetic Comparisons of Species (or populations)
Shows what has happened in past evolution
2. Biology of Natural Populations:
extent of individual variation (repeatability)
heritability and genetic correlations
natural and sexual selection
field manipulations and introductions
Shows present evolution in action
3. Selection Experiments
Shows, experimentally, what might happen during future
evolution
4. Compare Real Organisms with Theoretical Models
Shows how close selection can get to producing optimal
solutions
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http://www.google.com/search?hl=en&lr=&oi=defmore&defl=en&q=define:allometry
17 Jan. 2006
Definitions of allometry on the Web:
Generally, the effect of size on shape. Specifically, any relationship of anatomical variables that fits the
equation Y = AX k (A is a constant, the exponent k the coefficient of allometry).
www.modernhumanorigins.com/a.html
Change in a measurable aspect of an organism (such as shape) with increase or decrease in size.
www.csupomona.edu/~jcclark/classes/bio406/glossary.html
A disproportionate relationship between size of a body part and size of the whole body.
www.intuitive.com/coolsites/examples/ch5-1.html
The relationships between various aspects of a tree's size and shape. See the allometry topic for more.
www.sortie-nd.org/help/manuals/help/more_info/glossary.html
The study of the change in proportion of various body parts as a consequence of their growth at different
rates.
highered.mcgraw-hill.com/sites/0767430220/student_view0/glossary.html
The study of the relative growth of a part of an organism in relation to the growth of the whole
wordnet.princeton.edu/perl/webwn
Allometry is the science studying the differential growth rates of the parts of a living organism's body part or
process.
en.wikipedia.org/wiki/Allometry
83
http://www.google.com/search?hl=en&lr=&oi=defmore&defl=en&q=define:scaling
17 Jan. 2006
Definitions of scaling on the Web:
The act of arranging in a graduated series act of measuring or arranging or adjusting according to a scale
ascent by or as if by a ladder
wordnet.princeton.edu/perl/webwn
In Euclidean geometry, scaling is an affine, linear transformation that can enlarge or diminish an object by
certain factors. See also homothety.
en.wikipedia.org/wiki/Scaling_(geometry)
In computer networking, scaling is the ability for a network to continue to function with limited or no
degredation in performance as the number of users on the network increases.
en.wikipedia.org/wiki/Scaling_(computer_network)
The measuring of lengths and diameters of logs and calculating deductions for defect to determine volume.
www.woodlot.bc.ca/swp/myw/html/21_Glossary.htm
A means of calculating the amount of enlargement or reduction necessary to accommodate a photograph
within the area of a design.
www.purdue.edu/printingservices/support/glossary/glossrtoz.htm
The enlargement or reduction of an image or copy to fit a specific area.
www.millerbrosengraving.com/resources/glossary.html
Determining the proper size of an image to be produced (or reduced/enlarged). It is important that both
directions be scaled in order to ensure proper fit in the final reproduction.
www.relyprint.com/help_dictionary.html
Reduction or enlargement of artwork, which can be proportional (most frequently used) or disproportional.
In desktop publishing, optimal scaling of bitmaps is reduction or enlargement that will avoid or reduce moiré
patterns.
www.printingyoucantrust.com/glossary.cfm
Determining the proper size of an image to be reduced or enlarged to fit an area.
www.careydigital.com/support/glossaryr-s.html
84
… then tack on a paragraph about the adaptive
(evolutionary) significance of whatever they
found.
For example, consider the last paragraph of a
study that compared goats with dogs:
"In conclusion, we show that highly aerobic mammals
like dogs possess an “aerobic albumin” with elevated
fatty acid binding capacity. This adaptation allows
them to support much higher rates of circulatory fatty
acid transport than sedentary goats, but further
research is needed to determine whether all
endurance-adapted species have evolved such
albumin."
85
… then tack on a paragraph about the adaptive
(evolutionary) significance of whatever they
found.
For example, consider the last paragraph of a
study that compared goats with dogs:
"In conclusion, we show that highly aerobic mammals
like dogs possess an “aerobic albumin” with elevated
fatty acid binding capacity. This adaptation allows
them to support much higher rates of circulatory fatty
acid transport than sedentary goats, but further
research is needed to determine whether all
endurance-adapted species have evolved such
albumin."
How do we know dogs are endurance adapted?
86
… then tack on a paragraph about the adaptive
(evolutionary) significance of whatever they
found.
For example, consider the last paragraph of a
study that compared goats with dogs:
"In conclusion, we show that highly aerobic mammals
like dogs possess an “aerobic albumin” with elevated
fatty acid binding capacity. This adaptation allows
them to support much higher rates of circulatory fatty
acid transport than sedentary goats, but further
research is needed to determine whether all
endurance-adapted species have evolved such
albumin."
But what else differs between dogs and goats?