sure, it would be great to make BOTH big eggs

1
sure, it would be great to make BOTH big eggs
AND lots of them, but there's only so much yolk
to go around...so....
critters trade off egg size and egg number
...as well as a whole lot of other "life
history" parameters, such as growth versus
reproduction survival versus age at first
reproduction degree of parental care versus
number of offspring ...and so on
2
such trade-offs are excellent examples of
constraints, in this case perhaps physiological
in nature remember the horned beetles and
their trade-offs?
3
constraints can also be phylogenetic (also called
historical), developmental or genetic
what are some possible examples of these three
types of constraints, and what do they suggest
about evolution??
are constraints a hindrance to evolution?
4
Question 1. Subject Constraints  Do taxa with
richer and lengthier histories necessarily evolve
less than younger taxa that are less
"constrained?"  Does a group become
more historically constrained as it progresses
and evolves or doesn't evolve through time for
the simple fact that anything that did or didn't
happen  before it directly impact what it is
presently.  On a bigger scale, shall we expect to
see less evolution in all taxa as time progresses
as they all get temporally further from the
earliest unicellular common ancestors? Response
to Question 1.  I fear that we might be dealing
with taxonomic artifact.  It is true that some
ancient lineages (e.g., lungfish) persist but do
not speciate, whereas other lineages that are far
more recent (e.g., fishes of the family Cichlidae
or Percidae) have speciated greatly.  There are
some basal actinopterygian fishes (the larger
clade to which teleost fishes such as cichlids
and percids belong) that also are very poor in
numbers of species (for example, the families to
which the bowfin, Amia, belongs), but what you
see is that we just split off the ancient groups
to one side and keep progressing upwards toward
the large "progressive" groups.  If you carry
this far enough, in a cladistic diagram you would
have  a basal Amia as a sister group of all
teleosts, and a basal lungfish as a sister group
of all terrestrial vertebrates.  We are just
lucky to have a few of these basal groups still
hanging on!  Perhaps another way of looking at it
is to ask if we have ever had any basal lineages
that have just hung on for millions and millions
of years and then started speciating.  I cannot
think of any examples, but there may be some.
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Question 3. Topic          Evolutionary
Constraints Our question is whether constraints
result in directionality of evolution? For
example, Archaeopteryx had developed feathers
primarily for insulation then, feathers were
exapted for flight.  In present time, the most
abundant bird species are birds of flight.  Is it
possible that the development of  feathers
resulted in a constraint, thus keeping birds of
flight, as well as  flightless birds, from better
adapting to their environment through means 
other than flight?  Had there not been any
feathers, would flight have  been an
option?  Response to Question 3.         
Several authors have observed that what start out
in evolution as novelties sometimes turn into
constraints.  It is a little hard for me to think
of feathers as being constraining, though.  There
are lots of birds that have lost flight -- for
example, rails on oceanic islands.  There are
also birds that have become aquatic  or
semiaquatic (penguins, auks) and use feathers
only as insulation.  It is unlikely that birds
will ever become burrowing and wormlike, but that
is probably related to things in addition to
morphological features related to flight. 
Sometimes constraints at one level become
opportunities at another.  I have written about
one of these, the loss of lungs in salamanders. 
Most salamanders that lose lungs (and it has
happened in parallel in at least five separate
clades) live in and around rapidly flowing
streams (lungs seem to be of negative value in
such conditions they act like water wings and
bouy the animals up, causing them to lose their
grip on the substrate and be swept downstream. 
These animals have excellent cutaneous
circulation and exchange gases through the skin,
so the lungs are not missed as far as can be
determined).  Most of these lineages include
extreme stream-adapted specialists that have not
done much.  But in one group the loss of the
lungs seems to have freed up the lung-filling
mechanism and it has been coopted to become a
superb  tongue-projection mechanism.  This group
subsequently underwent a relatively enormous
amount of speciation, though cause and effect is
very difficult to sort out.
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Question 8. Question Is it possible that
developmental and structural options increase?
How much do constraints put on design novelty?
and Do complex cells increase in
complexity? Response to question 8. I am
not sure I understand the question. First, I do
like to think about constraints, but more as a
crutch than anything else. I see a bias in the
production of variation. Some workers find it
convenient to think that just the right kind of
variation and selection have not yet coincided.
I think in general that historical (i.e.,
phylogenetic and developmental) and formal (i.e.,
physical and architectural) constraints do limit
what can happen and bias what does along certain
lines. Constraints are not absolute in their
effects. For example, insects seem constrained
to produce bodies enclosed in chitin and composed
of three main kinds of segments, but they do not
seem to suffer for it! They are most unlikely to
produce bone, and even less likely to produce
bony internal skeleton for appendages. As to
the cell question -- I do not know. I am
uncomfortable with the classification system that
we use for cells, and we might be seeing a kind
of "taxonomic" artifact. Do complex cells give
rise to even more complex cells? It is a kind of
developmental question, since cells, like
organisms, are not "born " in one cell division,
but arise through a series of ontogenetic
tranformations. I suppose that complex cells
might undergo one more cell division to become
even more complex, or simpler, but I just do not
have the empirical background to say.