Mammal milk! Comparative study blogged!

I am excited (dare I say thrilled) to report that a paper I was involved with got blogged about!
 *Forgive the self-enthusiasm.  This is a first for me!*

This paper examines lactation in 129 species and was published this year (2013) in the Journal of Animal Ecology.

The paper is titled: "The evolution of the nutrient composition of mammalian milks" 

Authors: Amy L. Skibiel, Lauren M. Downing, Teri J. Orr and Wendy R. Hood

Article Summary:  
"1. In mammals, nutrient allocation during lactation is a critical component of maternal care
as milk intake promotes juvenile growth and survival, and hence maternal and offspring
fitness.
2. Milk composition varies widely across mammals and is hypothesized to have arisen via
selection pressures associated with environment, diet and life history. These hypotheses have
been proposed based on observations and/or cross-species comparisons that did not standardize
for stage of lactation and did not consider evolutionary history of the species in analyses.
3. We conducted the largest comparative analysis of milk composition to date accounting for
phylogenetic relationships among species in order to understand the selective advantage of
producing milk with specific nutritional profiles. We examined four milk constituents in association
with species ecology while incorporating phylogeny in analyses.
4. Phylogenetic signal was apparent for all milk constituents examined. After controlling for
phylogeny, diet and relative lactation length explained the greatest amount of variation in
milk composition. Several aspects of species’ ecologies, including adaptation to arid environments,
reproductive output and maternal body mass were not associated with milk composition
after accounting for phylogeny.
5. Our results suggest that milk composition is largely a function of evolutionary history,
maternal nutrient intake and duration of milk production. Arriving at these conclusions was
made possible by including the evolutionary relationships among species."



Read the blog entry by Katie Hinde here at:
http://mammalssuck.blogspot.com/2013/11/mega-mammal-milk-analysis.html

This paper was part of Amy Skibiel's dissertation work under the direction of Wendy Hood.  I've written about these two lovely ladies before as they were instrumental for helping me get my bat milk work up and running during my dissertation! 

Zoochosis Evolution! Fail lab- locomotion and evolution.

This video came to my attention recently and it's pretty fun/funny.  Here we learn about maximal sprint speed in association with an unfortunate human bicyclist and an seemingly aggressive ungulate.


Cast includes UCR biology professor Dr. Theodore Jr. Garland (re-from my alma mater)!

The show is interesting with a unique way to present science.   What do you think?


From their website: "Fail Lab is an irreverent new science series from filmmaker Patrick Scott, creator of the viral production company Zoochosis. Watch each week as the top minds in science dig deep to reveal the hidden lessons and wonders in the world's best fail videos."

Crowd funding and hemipenes

I know its been some time since I've posted a blog- but- it is time!  Why you might ask?  Well primarily because I have a few minutes to catch my breath and more importantly tell you about an exciting project that has been listed on Rockethub for crowd funding.

(If you need an photo to grab your curiosity look no further!)

Photo: C. Gilman (from http://www.rockethub.com/projects/21959-hemipenes-evolutionary-novelty-or-a-new-twist-on-an-old-trick)

This lovely project titled Hemipenes: evolutionary novelty, or a new twist on an old trick will investigate the development of hemi...wait did I say pens? that sounds sort of like 'penis'...  yes hemipens!  That's right two penises!  Lizards happen to have two (as do other squamates) but how do these two functional intermittent organs develop?  Do they develop the same way that a usual 'ol penis does?  Well- my dear friend and labmate Casey Gilman - has a project ready to go to find out!  Stop by her Rockethub page to see her COOL video to learn more!  (For example- do you find yourself curious if they use both at once?  Go to find out by watching Casey's video)!

Why should you care about hemipenes? 

Well according to Casey a PhD candidate at UMass Amherst "Because of differences in general morphology (two versus one), and some observable differences during development, hemipenes have been considered by some to be an evolutionary novelty. However, there is still no agreement about whether hemipenes and the single penis found in other amniotes are homologous (that is, they come from a common ancestor), or are indeed novel."

Ernst Haeckel, and the art of nature

Ernst Haeckle's art and to some degree life are encapsulated by Proteus an interesting film from David Labrun that presents the art side of Biology during Haeckle's life and time (mid to late 1800s). After viewing this film I thought it might be worth writing a little about Haeckle here.

Haeckle born in 1834 in Potsdam, Germany (then Prussia) was mentored in part by perhaps one of the most diversely brilliant minds of this time Wolfgang von Goethe (author of Faust, and a biologist in his own right). (Haeckle shown below left with a fellow field biologist Nicholi Miklouho-Maclay).

In his numerous books on biology Haeckle coined many terms still used in biology like 'ecology,' 'protist,' 'stem cell' and 'phylogeny' among others. He also presented an important idea during its time 'recapitulation theory' (i.e. phylogeny recapitulates ontogeny). With an interest in Darwin's ideas regarding natural selection and evolution, Haeckle examined ontogenetic (i.e. developmental) changes of various organisms and suggested that these followed evolutionary transition stages. A famous picture of his illustrating this is below but it is important to note that recapitulation is no-longer thought to be true. But, it at least spurred lots of research and thus was a valuable insight for its time. It is somewhat ironic that Haeckle's writing on the topic of evolution helped it catch on but that many of his ideas are no-longer supported by evolutionary research.

Haeckle is particularly interesting given his struggle throughout his early career regarding a decision to pursue art or biology. The rigor and seriousness of biology was surely in stark contrast with the aesthetic joy and beauty of colors and shapes that attracted Haeckle's eye. Indeed, he was an excellent landscape artist in addition to scientific illustrator. Luckily he trudged on and pursued both. He found great beauty in nature and to that we can be thankful as multiple tomes of his can be accessed with amazing illustrations of a suite of animal life.

Images of bats by E. Haeckel, including illustrated bat faces at the top of page.

The evolution of flight (Part 1)

Many animals are able to fly and most of these are insects. However, when one stops to consider which vertebrates fly (vertebrates are animals with an internal skeleton including a spine and something resembling a spinal chord) only 3 main groups are able to fly.

These are: birds, Pterosaurs and bats.

The wing surface formed in 3 different ways one for each of these groups (see above).

Both bats and Pterosaurs used a wing-surface created by finger elongation (the 'pinkie' in Pterosaurs and all fingers elongated except the 'thumb' in bats).

Meanwhile, birds fly using a surface created by modified scales (feathers) and a strong series of arm and finger bones that are the result numerous bones fusing. Additional details are left out for brevity but are extremely interesting such as skeletal lightening in birds.

Pterosaurs are extinct and so only two extant flying vertebrate groups (extant = animals that are still alive today) are bats and birds. (What is a Pterosaur? Click here!)

Why did flight evolve?

There are two main thoughts about this. Basically either animals were able to flap and lift UP to escape predators etc. OR they were living in trees and started to glide from tree to tree (like 'flying' squirrels) also to catch food (insects) or avoid predators.

Regardless, the sky is (and was) full of potential food and once they were able to fly bats quickly filled a new niche (a niche is the ecological role of an animal generally relating to the food it eats). Both bats and birds were able to eat flying insects but bats as nocturnal animals compete with a fewer set of birds. Indeed this successful niche 'nocturnal insectivore' has since been radically expanded to include other more unusual food-types such as frogs or fish!

You can read more about the evolution of flight here.

Click here for cool videos of bats flying in slow motion.

For my next I will try to summarize the physics required for flight.