Scientific Illustration

greynotgrey:

She blinded me with science

A. Fore-limb of Monkey B. Fore-limb of Whale

WHAT IS MEANT BY HOMOLOGY? ESSENTIAL SIMILARITY OF ARCHITECTURE, THOUGH THE APPEARANCES MAY BE VERY DIFFERENT

This is seen in comparing these two fore-limbs, A, of Monkey, B, of Whale. They are as different as possible, yet they show the same bones, e.g. SC, the scapula or shoulder-blade; H, the humerus or upper arm; R and U, the radius and ulna of the fore-arm; CA, the wrist; MC, the palm; and then the fingers.

from The Outline of Science by J. Arthur Thomson; section THE GEOLOGICAL MIDDLE AGES

The Cambrian Explosion: The Construction of Animal Biodiversity

By Erwin, Douglas Valentine, James

See also: The Weird Youth of the Animal Kingdom by Carl Zimmer

“The cetacean section of the composite phylogenetic hypothesis for Artiodactyla. Thickened colored bars above branches (D–Z and a–j) mark optimizations of various evolutionary changes within Cetacea (see Table 1). The three S = F symbols (blue and brown) are positioned on branches where parallel moves from saltwater to freshwater environments are inferred in the river dolphins – Inia, Lipotes, and Platanista. Thick branches connect extant taxa in the tree, and thin branches represent extinct lineages. The small, inset tree delimits (in gray) the section of the overall composite topology (Fig. 7) that is shown here at a larger scale. Approximate evolutionary time-scale, in millions of years, is at the base of the figure. For the mysticete section of the tree, one of the six minimum length trees derived from the Mysticeti supermatrix is shown. Relationships derived from the Artiodactyla supermatrix (stem Cetacea) and from the crown Cetacea supermatrix (Odontoceti) are based on strict consensus trees. Artwork is by Carl Buell. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)”

A phylogenetic blueprint for a modern whale. Gatesy J, Geisler JH, Chang J, Buell C, Berta A, Meredith RW, Springer MS, McGowen MR. Mol Phylogenet Evol. 2012 Oct 26. pii: S1055-7903(12)00418-6. doi: 10.1016/j.ympev.2012.10.012. (pdf)

“The non-cetacean section of the composite phylogenetic hypothesis for Artiodactyla. Thickened colored bars above branches (A–C) mark optimizations of various evolutionary changes on the lineage that leads to Cetacea (see Table 1). Gray bars above branches (1–3) indicate character state changes that are interpreted as convergences between early stem whales (see Fig. 9) and mesonychians. Thick branches connect extant taxa in the tree, and thin branches represent extinct lineages. The small, inset tree delimits (in gray) the section of the overall composite topology (Fig. 7) that is shown here at a larger scale. Approximate evolutionary time-scale, in millions of years, is at the base of the figure. Relationships derived from the Artiodactyla supermatrix are based on a strict consensus of trees. Artwork is by Carl Buell.”

A phylogenetic blueprint for a modern whale. Gatesy J, Geisler JH, Chang J, Buell C, Berta A, Meredith RW, Springer MS, McGowen MR. Mol Phylogenet Evol. 2012 Oct 26. pii: S1055-7903(12)00418-6. doi: 10.1016/j.ympev.2012.10.012. (pdf)

elegantbuffalo:

Parallel Evolution: when similar characterisitcs arise in closely related organisms

Most people who have studied even a little evolutionary biology are aware of the marvelous diversity of the Lake Victoria cichlids. These fish have radiated to fill nearly all available niches in the lake. Over only a few million years, 300 species were developed from one ancestral populations.

What you may not know is that there are cichlids in Lake Malawi and Lake Tanganyika, too, and all originated from similar ancestral populations. What’s more, the cichlids in each of the three lakes have evolved to fill nearly the exact same niches. The correspondence in ecology and morphology between the fish of the three lakes is the most spectacular example of parallel evolution that I’ve seen. Take a look at this figure, where the fish on the left come from Lake Tanganyika and the ones on the right are from Lake Malawi.

kewl.

marywilliams:

Whale Phylogeny work in progress. Once this is completed it’ll be going with a handful of sketches to an editor for a book proposal.

Colored Pencil and Digital. 11”x14”

rhamphotheca:

Walking With Sea Cows, Closing the Gap

by Brian Switek

Sea cows once walked on land. Pezosiren leaves no doubt of that.

This roughly 48 million year old mammal once trod over prehistoric Jamaica, and looked akin to a hippo with the skull of a manatee. Much like Pakicetus in the history of early whales, Pezosiren embodies a critical transitional period in the evolution of manatees and dugongs, yet the place where this amphibious sea cow was found did not match what paleontologists expected.

In the big picture of mammalian evolution, sea cows are paenungulates – members of a group that also encompasses hyraxes, elephants, and extinct branches such as the double-horned Arsinoitherium and the aquatic desmostylians.

The earliest members of these lineages first appear in Africa shortly after the end-Cretaceous extinction of 66 million years ago, with the perplexing exception of the sea cows. The earliest, most archaic progenitors of today’s manatees and dugongs, such as Pezosiren, have been found in Jamaica. Anatomical and genetic evidence is clear that sea cows must have shared an African origin with the other paenungulates, but, until now, no one has picked up the fossil trail of the earliest sirenians.

Today, in PLoS One, paleontologist Julien Benoit and colleagues describe a bone from the Eocene of Tunisia that closes the geographical gap in the sea cow backstory…

(read more: National Geo)

(images: T -uncredited; BL -by TheSuperMat | Wikipedia ; BR - Benoit et al., PLoS ONE)

“Phylogenetic relationships of extant Mysticeti (baleen whales) based on combined parsimony analysis of 23 datasets. Filter-feeding mode of each mysticete family is shown (A–C)”

A phylogenetic blueprint for a modern whale. Gatesy J, Geisler JH, Chang J, Buell C, Berta A, Meredith RW, Springer MS, McGowen MR. Mol Phylogenet Evol. 2012 Oct 26. pii: S1055-7903(12)00418-6. doi: 10.1016/j.ympev.2012.10.012. (pdf)

The “Atlas of Creation” is a book by Turkish creationist Harun Yahya (the pen name of Adnan Oktar) it purports to show that fossils are identical to living creatures and so evolution hasn’t happened or something. This book is riddled with bizarre errors for example in the image above, a Fossil crinoid, is shown with recent sabellid fan worms that are presented as being identical even though they don’t even belong to the same phylum (Echinodermata & Annelida respectively).

This image comes from an excellent paper outlining some of Harun Yahya’s errors:

Taxonomy alive and kicking: or how taxonomy can help debunking creationist thinking. Thierry Backeljau, Kurt Jordaens, Antonio M. de Frias Martins. AÇOREANA, 2011, Suplemento 7: 241-291 (Pdf)

If anyone is feeling industrious translating this papers into Turkish would a good thing to do!

See also:

The evolution of Harun Yahya’s “Atlas of Creation”

The Skulls That Make Harun Yahya Look Like a Bonehead 

rhamphotheca:

Penguin Evolution

Penguins are unusual birds in that they cannot fly and are instead proficient swimmers and divers. Evolutionary biologists have long wondered how penguins evolved their peculiar traits and how some of their kind conquered the bitterly cold Antarctic. Recent fossil discoveries have enabled researchers to piece together the penguins’ evolutionary past, revealing that some of the traits that fortify them against the cold evolved under warm conditions. Although penguins have triumphed over 60 million years of climate change, current warming conditions may outpace their ability to adapt…

CLICK HERE TO SEE IMAGE IN LARGER FORMAT

(Art by Stephanie Abramowicz, Maps by XNR Productions)

(source: 10.1038/scientificamerican1112-56)

(via: Nova Taxa)

(via prehistoric-birds)