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- Depositor
- Karen Dykes
- Date Uploaded
- 2021-12-08
- Date Modified
- 2021-12-08
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- passed on August 08, 2024 at 14:06
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| Transcript |
- Met one of our former students -
a faculty possibility
Dr H.L. Saunders Ph.D. Yale
now at Woods Hole
main field Benthic communities
but has studied plankton.
In Brit [British] Museum saw the following
Mollusc types
Dentalium semipolatuum [2 illegible words]
" [Dentalium] pretiosum Savady[?]
Yoldia vancouverensis Smith
" [Yoldia] ensifera
Astarte esquimalti Baird
Psephidia lordi Baird
Types supposedly there but not found
are Astocina exinus [?]
Colus spitbergensis
Tryphon tenuisculptus.
Yoldia limatula Say.
July 17. London
This morning went first to the sessions
on the origin + stabilization of species
+ heard a paper by J.M. Thaday[?] of
Sheffield on the effect of disruptive selection
on the characteristics of a pop [population] of Drosophila
I have a copy of his paper. He has
selected from both extremes of a Drosophila
pop. [population] for bristle number. The results
are significant + show importance of
disruptive selection as against stabilizing
selection in maintaining variation + in
changing the genotype + phenotype.
G.Y. Bey-Bienker of Leningrad then gave a
paper on the Principle of Change in
stations + the problem of initial divergence of
species. Using birds + insects be showed
in a broad N [north] - S [south] range there is often a
shifting of habitat by the species. His graph
[Drawing of graph]
Xenophyl. Mesophyl. Hygrophy.
Forest
Forest Steppe
Steppe
Semidesert
The shift in habitat takes place in the
direction of the arrows. Thus forms
hygrophyllic in the north cannot spread into
the s.[southern] drier zones, while xerophyles of the
north can enter the southern drier areas
by taking to wetter habitats. Thus change of
heat budget can be compensated for in
past by altering the habitat.
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