biomedicalephemera: Latimeria chalumnae - Coelacanth The coelacanth was assumed extinct until 1938, since fossils of it had been found long before, yet hadn’t ever been caught by anyone who recognized it (it was known as the “gombessa” by the Comoro Islands fishermen, and was considered a worthless fish to be disgarded, as it tasted awful). It’s thought to have evolved over 400 million years ago, and were originally assumed to have gone extinct in the Late Cretaceous period. The Search Beneath the Sea: The Story of the Coelacanth. J.L.B. Smith, 1956.
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biomedicalephemera:

Latimeria chalumnae - Coelacanth

The coelacanth was assumed extinct until 1938, since fossils of it had been found long before, yet hadn’t ever been caught by anyone who recognized it (it was known as the “gombessa” by the Comoro Islands fishermen, and was considered a worthless fish to be disgarded, as it tasted awful). It’s thought to have evolved over 400 million years ago, and were originally assumed to have gone extinct in the Late Cretaceous period.

The Search Beneath the Sea: The Story of the Coelacanth. J.L.B. Smith, 1956.

(via biomedicalephemera)

skeptv:

How life came to land - Tierney Thys

View full lesson: http://ed.ted.com/lessons/how-life-came-to-land-tierney-thys

Spiders and crustaceans, also known as arthropods, led the charge from water to land—now outnumbering all terrestrial animals. But what about arthropods makes them so adaptable to life on land? Marine biologist Tierney Thys, and Noé Sardet and Sharif Mirshak of the Plankton Chronicles Project, shows us a world of fascinating animals and their habitats.

Lesson by Tierney Thys, visualization by Noé Sardet and Sharif Mirshak (Plankton Chronicles Project, Parafilms).

by TED Education.


rhamphotheca: _____________________________________________________ Early humans linked to large-carnivore extinctions Hominins could have triggered broad changes to the numbers and diversity of meat-eaters in Africa, researcher says. by Jeff Tollefson  (26 April 2012) Animal lovers around the world know modern otters as cute, playful and unthreatening. But the mustelid’s giant cousins in ancient Africa may have engaged in a life-and-death competition with humanity’s ancestors — and come out on the losing end. The demise of the gigantic ‘bear otter’ (Enhydriodon dikikae) was part of a broader decline in large-carnivore diversity in Africa, which accelerated around 2 million years ago — roughly the time that the first representatives of the genus Homo appeared on the scene. Lars Werdelin, a curator at the Swedish Museum of Natural History in Stockholm has been building a case that our forebears had something to do with the change. Although direct evidence of any causal connection is sorely lacking, Werdelin says, the transition in the carnivore fossil record coincides nicely with advances in tool-making and dietary shifts among early hominins. “The way I see it, this is one of the first ways in which we manipulated our environment on a large scale,” says Werdelin, who presented his latest findings at a symposium on human evolution and climate change at Columbia University’s Lamont-Doherty Earth Observatory in Palisades, New York. Werdelin argues that hominins may have competed indirectly with some of these carnivores by occupying prime habitat, thus forcing the animals to change their behavior without ever coming into direct contact with them. In some cases, the hominins may have out-competed carnivores directly by forcing them to surrender fresh kills. Regardless, the emergence of early humans could have cascaded through the food chain — ultimately wiping out many of Africa’s larger meat-eaters… (read more: Nature)               (images via NovaTaxa: TR - Victor Leshyk; B - Cal. Academy of Sci.)
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rhamphotheca:

_____________________________________________________

Early humans linked to large-carnivore extinctions

Hominins could have triggered broad changes to the numbers and diversity of meat-eaters in Africa, researcher says.

by Jeff Tollefson  (26 April 2012)

Animal lovers around the world know modern otters as cute, playful and unthreatening. But the mustelid’s giant cousins in ancient Africa may have engaged in a life-and-death competition with humanity’s ancestors — and come out on the losing end.

The demise of the gigantic ‘bear otter’ (Enhydriodon dikikae) was part of a broader decline in large-carnivore diversity in Africa, which accelerated around 2 million years ago — roughly the time that the first representatives of the genus Homo appeared on the scene. Lars Werdelin, a curator at the Swedish Museum of Natural History in Stockholm has been building a case that our forebears had something to do with the change. Although direct evidence of any causal connection is sorely lacking, Werdelin says, the transition in the carnivore fossil record coincides nicely with advances in tool-making and dietary shifts among early hominins.

“The way I see it, this is one of the first ways in which we manipulated our environment on a large scale,” says Werdelin, who presented his latest findings at a symposium on human evolution and climate change at Columbia University’s Lamont-Doherty Earth Observatory in Palisades, New York. Werdelin argues that hominins may have competed indirectly with some of these carnivores by occupying prime habitat, thus forcing the animals to change their behavior without ever coming into direct contact with them. In some cases, the hominins may have out-competed carnivores directly by forcing them to surrender fresh kills. Regardless, the emergence of early humans could have cascaded through the food chain — ultimately wiping out many of Africa’s larger meat-eaters…

(read more: Nature)              

(images via NovaTaxa: TR - Victor Leshyk; B - Cal. Academy of Sci.)

(via scientificillustration)

Source: rhamphotheca

skeptv:

Rebutting Brad Harrub: Haeckel’s Embryo Fraud

Ernst Haeckel was an amazing scientist at a crucial time in the history of biology. The legend of his fraud is largely manufactured.

His work reflected a certain ignorance of comparative embryology, and he probably skewed his illustrations to demonstrate his own theory, the biogenic (or “biogenetic”) law. There is no evidence he was every convicted of fraud, he was not “kicked out” of the University of Jena, and all of Dr. Brad Harrub’s assertions are based on poor research and factually false claims made by creationist author Jonathan Wells in his book “Icons of Evolution”.

So, let’s be clear on something that is often confused.
1. Haeckel’s illustrations were an attempt to prove his own biogenic law, not evolution.
2. Comparative embryology, the similarities between tissues during development, show the same branching pattern that is seen in phylogenetics. That is, closely related organisms show very similar stages of development. THIS is the actual evidence for evolution to be taken from pictures of embryos found in textbooks.

Evolution of development (“evo-devo”) has been one of the most productive areas of biology of the last two decades. Arguing that Haeckel’s failure to prove his biogenetic law somehow affects the value of comparative embryology to demonstrate evolutionary relatedness is just false.

My apologies for the bad camera work. This was mid-way through the talk, and the seats were very uncomfortable. The “jiggling” was me adjusting my position and having to move my phone hand to relieve the strain.

skeptv:

New Fossils Extend Branches of Family Tree

Interpretation of fossil finds and what they imply about human evolution often mean different things to different scientists. To many, evidence shows that the sequence of species in the Homo genus followed a linear route, from Homo habilis to Homo erectus and eventually to Homo sapiens. To other scientists, the Homo fossil record points to a bushy, branching tree rather than a single stem. Two new finds from the rich deposits around Koobi Fora ridge in Kenya’s Lake Turkana basin add more conclusive evidence that our ancestral tree branched with species that often occupied the same time periods and the same regions. Some species evolved on their own paths and died out, leaving no ancestors, while others eventually developed into new forms.

The discovery team, which was led by University College London anthropologist Fred Spoor and Meave Leakey of the National Museums of Kenya, has identified the fossils—a jaw and a skullcap—as belonging to Homo habilis and Homo erectus, respectively. The fossils date to similar time periods, supporting the notion that multiple species coexisted in this lake basin, and that they did so for almost half a million years. This Human Bulletin places these fossils in context with other Homo species and the ancestral path to humans.

skeptv:

Shed Science: The selfish gene behind altruism

With the aid of chocolates, find out how altruistic behaviours can only be explained by Dawkins’ selfish gene, our best way of thinking about Darwinian natural selection. This Shed Science examines how our views on natural selection have changed over time, from the Origin of Species, to group selection, to our current view; gene-centred evolution or the ‘selfish gene’.

Ask questions on Twitter: http://twitter.com/sallylepage/

My blog on this video, including more information about why Hymenoptera are so special, references and photo credits: http://sallylepage.com/blog/

If you haven’t already read The Selfish Gene, I can’t recommend it highly enough, and many of my non-biologically minded friends have enjoyed it as well! It’s really well written and is partly aimed at non-scientists. Even if you hate Dawkins (as I know many do), you should at least read Chapter 11, as this is where the term ‘meme’ is first coined. That’s right, you have Dawkins to thank for all those annoying images!

My website: http://sallylepage.co.uk/

New flu virus found in seals concerns scientists

shychemist:

Harbour seals in New England were found to be infected with the new strain

Scientists in the United States have identified a new strain of influenza in harbour seals that could potentially impact human and animal health.

The H3N8 flu has been associated with the deaths of harbour seals in New England last year.

Researchers say the virus may have evolved from a type that had been circulating in birds.

They say the discovery highlights the potential for pandemic flu to emerge from unexpected sources.

Researchers were puzzled by the mysterious deaths from pneumonia of 162 harbour seals around the coast of New England last year.

Autopsies on five of the marine mammals indicate that they died from a type of H3N8 influenza A virus that is closely related to a strain circulating in North American birds since 2002.

[…]

As well as mutating to live in both animals and birds the scientists say this flu has evolved to make it more likely to cause severe symptoms. The virus also has the ability to target a protein found in the human respiratory tract.

Dr Anne Moscona of Weill Cornell Medical College in New York City edited the report and says that the new virus is a worry.

“There is a concern that we have a new mammalian-transmissible virus to which humans haven’t yet been exposed. It’s a combination we haven’t seen in disease before.”

Click title to read more.

laboratoryequipment: Bird Lice Evolved to Form Body Part-Specific SpeciesBirds of a feather flock together and – according to a new analysis – so do their lice.A study of the genetic heritage of avian feather lice indicates that their louse ancestors first colonized a particular group of birds (ducks or songbirds, for example) and then “radiated” to different habitats on those birds – to the wings or heads for instance- where they evolved into different species. This finding surprised the researchers because wing lice from many types of birds look more similar to one another than they do to head or body lice living on the same birds.Read more: http://www.laboratoryequipment.com/news/2012/08/bird-lice-evolved-form-body-part-specific-species
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laboratoryequipment:

Bird Lice Evolved to Form Body Part-Specific Species

Birds of a feather flock together and – according to a new analysis – so do their lice.

A study of the genetic heritage of avian feather lice indicates that their louse ancestors first colonized a particular group of birds (ducks or songbirds, for example) and then “radiated” to different habitats on those birds – to the wings or heads for instance- where they evolved into different species. This finding surprised the researchers because wing lice from many types of birds look more similar to one another than they do to head or body lice living on the same birds.

Read more: http://www.laboratoryequipment.com/news/2012/08/bird-lice-evolved-form-body-part-specific-species

maschup: The ‘Crust of the Earth as Related to Zoology,’ presenting, at one glance, the ‘distribution of the principle types of animals, and the order of their successive appearance in the layers of the earth’s crust,’ published by Louis Agassiz and Augustus Addison Gould as the frontispiece of their 1848 Principles of Zoölogy. The diagram is like a wheel with numerous radiating spokes, each spoke representing a group of animals, superimposed over a series of concentric rings of time, from pre-Silurian to the ‘modern age.’ According to a divine plan, different groups of animals appear within the various ‘spokes’ of the wheel and then, in some cases, go extinct. Humans enter only in the outermost layer, at the very top of the diagram, shown as the crowning achievement of all Creation. (Brainpickings)
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maschup:

The ‘Crust of the Earth as Related to Zoology,’ presenting, at one glance, the ‘distribution of the principle types of animals, and the order of their successive appearance in the layers of the earth’s crust,’ published by Louis Agassiz and Augustus Addison Gould as the frontispiece of their 1848 Principles of Zoölogy. The diagram is like a wheel with numerous radiating spokes, each spoke representing a group of animals, superimposed over a series of concentric rings of time, from pre-Silurian to the ‘modern age.’ According to a divine plan, different groups of animals appear within the various ‘spokes’ of the wheel and then, in some cases, go extinct. Humans enter only in the outermost layer, at the very top of the diagram, shown as the crowning achievement of all Creation. (Brainpickings)