The Geospizinae beaks were adapted to the different environments they lived in.
The size and shape of the beak were seen as distinguishing features. It was Darwin’s collections of Geospizinae, known as Darwin’s finches, which were the most influential.
#DARWIN BIRD SKETCH PLUS#
The crew of the HMS Beagle captured 48 tortoises plus two small tortoises that were eaten on the journey home. Darwin was always keen to try new food and was quite taken with the taste of tortoise. Much to Darwin’s amusement he frequently got on the tortoises back and “then giving a few raps on the hinder part they would rise and walk away”, but he said it was difficult to keep balance. However tortoises did not receive the same criticism and the crew were rather taken with these giant animals. The iguanas were described as “most disgusting reptiles”. 12 Such latent tendency w d be shown by their producing the red feathers when old or diseased in their ovaria.Darwin noted that there was little flora and said he “did not see one beautiful flower”. It is not enough that females sh d be produced from the males with red feathers, which should be destitute of red feathers but these females must have a latent tendency to produce such feathers, otherwise they would cause deterioration in the red head feathers of their male offspring. I fear this letter will trouble you to read it.- A very short answer about your belief in regard to the ♀ finches & gallinaceæ would suffice.-īelieve me | My dear Wallace | Yours very sincerely | Ch Darwin I value the cases of bright-coloured, incubating male fishes 10-& brilliant female butterflies, solely as showing that one sex may be made brilliant without any necessary transference of beauty to the other sex for in these cases I cannot suppose that beauty in the other sex was checked by selection.- 11 I fear we shall never quite understand each other. I grieve to differ from you, & it actually terrifies me & makes me constantly distrust myself. 5 I am quite willing to admit that the female may have been modified, either at the same time or subsequently, for protection by the accumulation of variations limited in their transmission to the female sex.- I owe to your writings the consideration of this latter point.- 6 But I cannot yet persuade myself that females alone have often been modified for protection.- Should you grudge the trouble briefly to tell me, whether you believe that the plainer head & less bright colours of ♀ chaffinch,-the less red on the head & less clean colours of ♀ gold-finch-the much less red on breast of ♀ Bull-finch-the paler crest of Golden-crest Wren-&c-have been acquired by them for protection.- 7 I cannot think so anymore than I can that the considerable differences between ♀ & ♂ House Sparrow-or much greater brightness of ♂ Parus cæruleus (both of which build under cover) than of ♀ Parus, are related to protection.- 8 I even misdoubt much whether less blackness of ♀ Blackbird is for protection.-Īgain can you give me reason for believing that the modest differences between female Pheasants, the female Gallus bankiva, female of Black-Grouse-the PeaHen-female Partridge, have all special reference to protection under slightly different conditions.- 9 I of course admit that they are all protected by dull colours, derived, as I think, from some dull-ground progenitor & I account partly for their difference by partial transference of colour from the male & by other means too long to specify but I earnestly wish to see reason to believe that each is specially adapted for concealment to its environment. I find it most difficult but not, I think, impossible to see how, for instance, a few red feathers appearing on the head of a male bird, & which are at first transmitted to both sexes, could come to be transmitted to males alone 4 XXX but I have no difficulty in making the whole head red if the few red feathers in the males from the first tended to be sexually transmitted. I think we start with different fundamental notions on inheritance. 3 We differ, I think, chiefly from fixing our minds perhaps too closely on different points, on which we agree: I lay great stress on what I know takes place under domestication. 2 To answer it would require at least 200 folio pages! If you could see how often I have rewritten some pages, you would know how anxious I am to arrive as near as I can to the truth. I am very much obliged for all your trouble in writing me your long letter, which I will keep by me & ponder over.
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