Tag Archives: biology

Sharks are now oversharing…but you will want to follow them!

Published by on in Distinguished Lectures
Reply

half-mount2-blogYoung or old, nature lover or couch potato—everyone has some fascination with sharks.

HMNS is bringing in some great opportunities to learn about these predators who have dominated the oceans for millions of years. Leading shark researchers will be at HMNS during the next two weeks to share the latest information on our local sharks in the Gulf of Mexico and the grand-daddy of them all, the great white.

On February 25 marine biologist Dr. Glenn Parsons from Ole Miss will share the findings of his 40-year career of researching shark behavior, ecology and physiology in the Gulf of Mexico, which harbors about 65 species of sharks. Sharks here are exposed to both natural stressors including changes in water temperature and oxygen availability and anthropogenic stressors that are caused by humans, pollutants and fisheries.

This is Katherine getting her and tag checkup aboard the OCEARCH vessel.

This is Katherine getting an ultrasound and tag checkup aboard the OCEARCH vessel.

Unprecedented research on great white sharks and other large apex predators will be presented by shark researcher Dr. Greg Stunz of the Harte Institute and Texas A&M Corpus Christi with OCEARCH founder and expedition leader Chris Fischer on March 4. In order to protect the species’ future while enhancing public safety and education, researchers with the OCEARCH collaborative are now generating previously unattainable data on the movement, biology and health of great white sharks. The images they will show on the Wortham Giant Screen will be insanely amazing.

Of course you can also get up close and personal with two different shark species at the Museum in the Shark! touch tank experience, where biologists will share shark tales and shark tails.

HMNS Distinguished Lectures

“The ABC’s of Sharks: Attacks, Biology and Conservation”
Glenn Parsons, Ph.D., Ole Miss
Wednesday, February 25, 6:30 p.m.

“Great White Sharks, Tracking The Ocean’s Apex Predator”
Greg Stunz, Ph.D. and Chris Fischer, OCEARCH
Wednesday, March 4, 6:30 p.m.

Tickets & more info: www.hmns.org/lectures

Need to keep up with a busy shark who is always on the go?
Now you can stay connected to your favorite shark via a phone app, Twitter and Facebook!

shark-tracker-app-iconOCEARCH’s Global Shark Tracker app lets you observe the navigational pattern of sharks that have been tagged with satellite tracking technology all for the purpose of shark conservation.

OCEARCH facilitates unprecedented research by supporting leading researchers and institutions seeking to attain groundbreaking data on the biology and health of sharks, in conjunction with basic research on shark life history and migration.

OCEARCH is a leader in open source research, sharing data in near-real time for free through the Global Shark Tracker, enabling students and the public to learn alongside PhDs. The Landry’s-developed STEM Education Curriculum, based on the Global Shark Tracker and Next Generation Science Standards (NGSS), is being launched for grades 6-8 in the fall of 2013 nationwide.

Over 50 researchers from more than 20 institutions have collaborated with OCEARCH to date with over three dozen research papers in process or completed. Research expeditions are conducted worldwide aboard the M/V OCEARCH, which serves as both a mothership and at-sea laboratory. Utilizing a custom 75,000 lb. capacity hydraulic platform designed to safely lift mature sharks for access by a multi-disciplined research team, up to 12 studies are conducted in approximately 15 minutes on a live mature shark. Powered by five Cat engines, the M/V OCEARCH is capable of Global Circumnavigation.

Here are screenshots showing the favorite hangouts of Wyatt, Sam Houston and Madeline—a few sharks in our neighborhood. 

Screen-Shot-2015-01-22-at-2.39blog

Screen-Shot-2015-01-22-at-2.38blog

Screen-Shot-2015-01-22-at-2.40blog

 

Send your girls careening toward a career in hard sciences with HMNS summer camps

Published by on in Education
Reply

Let your young lady soar with HMNS’ Careers in Science program, designed to encourage girls to explore, well, careers in science!

Girl Scouts - Careers In Science
The Careers in Science curriculum offers three classes: Paleontology, Biology and Chemistry.

Careers In Science: Paleontology

At the Paleontology class, participants meet off-site and dig into history to uncover 45 million-year-old fossils from locations on the banks of the Brazos River and at a park teeming with petrified wood. Each participant keeps the fossils she finds!

Girl Scouts - Careers In Science
In Biology class, participants go behind the scenes of the Cockrell Butterfly Center to learn where our butterflies are sourced, how the plants are grown and even how our waterfall works. They’ll also interact with live insects and learn just what makes our “containment room” so important.

Girl Scouts - Careers In Science
Finally, Chemistry class teaches participants about everyday chemical reactions through hands-on experiments, including creating chemical temperature changes and understanding the role chemical reactions play in cooking.

Siblings at least 10 years of age can also participate in class with the purchase of a ticket, and each class ticket allows one adult to accompany each child.

Email scouts@hmns.org or check out the website for more information. You can also sign up for our monthly Scouts newsletter and be the first to learn about upcoming classes!

The Eyes Have It: Evolutionary Development and DNA

Published by on in Science
Reply

Today’s guest blogger is Neal Immega. He has a Ph.D. in Paleontology and is a Master Docent here at HMNS. In his post below – originally printed in the Museum’s volunteer newsletter – Neal discusses Evolution Development and DNA.

Popular media crime shows, like CSI: Crime Scene Investigation, show amazing applications of DNA technology. For example, a person can be traced to a specific location by means of cells he left on a door knob.

A new science called “Evo-Devo,” shorthand for Evolutionary Development, can tell us even more amazing information. Evo-Devo techniques probe deeply into the structures of DNA to look at how DNA actually codes for the growth of body parts, telling us more about the animal kingdom than we ever dreamed possible. It shows genetic similarities between very different organisms and lets us understand how two organisms, like mice and men, can have DNA that is 85% similar and, yet, code for very different organisms.

We all know the basics of DNA molecules, where the genetic code is stored by a very long sequence of four proteins strung together in various arrangements. That is the easy part! What we need to
worry about is how these genes blueprint a living being. Geneticists, like Sean Carroll (whose popular books are listed in the references box), have discovered that the DNA code is made up of some large master programs that control things, such as eyes, and lots of very small programs (they call them switches) that control what kind of eye will be displayed.

Normal Fruit Fly
Image courtesy of The Exploratorium

Let’s confine ourselves to understanding and experimenting on simple life forms, such as fruit flies. To figure out which specific piece of DNA causes some feature to appear in a developing embryo, geneticists experimentally inactivate a segment of DNA, transplant the complete strand (including the inactivated segment) back into the egg, fertilize that egg, and then see what turns up missing. If that missing part is not vital for survival, the egg might even grow into an adult fly. Compare the drawings of a normal fly with the one below it where the master program for eyes has been deleted.

Eyeless Fruit Fly 
Image courtesy of The Exploratorium

Such experiments have found that the master program for making eyes can cause an eye to grow on a fly’s leg, body, antenna, or inside the body, depending on where it is placed on the DNA strand. Check out the drawing showing the results of moving the master program for legs to the site of the antenna. Note that the extra legs are fully formed but lack the neuron connections to the brain and so are not functional. (In the references box is a link to an electron microscope image of a real fruit fly that shows a mutation in which eyes replace antennae.)

Various mollusks (like clams, snails, and octopuses) grow eyes that vary in complexity from very simple sensitive pits to complex eyes that would compete well with human eyes. The EXACT SAME eye master program from a fruit fly can replace the eye master program for a squid, and it will grow a perfectly functional squid eye. You might be tempted to say that fruit flies and squids are cousins.

Fruit fly with extra legs
replacing the antennae 
Image courtesy of The Exploratorium

That is an amazing statement, but to take it even further, the same experiment with a mouse eye master program will grow fly eyes on flies and squid eyes on squids. They only differ by the small switch segments. These experiments establish a link between vertebrates and invertebrates that paleontologists are unlikely to find in the rock record. This also helps explain the amazing degree of structural similarity between mice and men—although many of the master programs are similar, the really critical parts of the DNA are the small switches that control the details.

Mollusks have just one master program that is controlled by different switches. Pectens, for example, have the most complex vision arrangement of any animal with three different types of eyes on its body. The DNA can be experimentally adjusted to grow any of these eyes anywhere on the body. Random mutations could thus cause novel arrangements, and survival would judge their fitness—evolution in action.

The switch concept explains how mice, chimps, and humans can have a similar number of genes. The switches control the result of the master programs. You can pick up any modern textbook and read that men and chimps have nearly identical genes. It is the switches that make us different and that provide the evolutionary means for dramatic changes, good and bad.

The fossil record is full of cases where a dramatic new species just appears. Paleontologists have often wondered if this was caused by a missing rock interval, by migration, or by rapid evolution. The concept of rapid evolution has often been discounted because it seemed to violate the incremental nature of evolution. We now can see how rapid evolution may just be a single point mutation in a switch. There are numerous biological examples where altering one protein is lethal, as in Tay-Sachs disease, or altering another might bear strongly on survival, as in changing
the color of hair from white to black.

Geneticists can now explain things in a way that profoundly affects how we think about evolution. Biologists and paleontologists have always wondered if evolution had to generate complex structures like eyes from scratch for each phylum. The reuse of master programs from very simple life forms through complex ones means that evolution can build on what went on
before. Critics of evolution often claim that eyes are too complex to have evolved. (The “half-an-eye-is-nogood” argument is derived from the first sentence of the Darwin quote in the box below.) Now, with Evo-Devo tools, we can see commonalities between the genetics of simple life forms and complex life forms– between clams and people.

The possibilities just became more complex.

REFERENCES:
Wyoming Dinosaur Center: http://www.wyodino.org/

Sean B. Carroll:
Endless Forms Most Beautiful: The New Science of Evo-Devo, (paperback) 2006
The Making of the Fittest: DNA and the Ultimate Forensic Record of Evolution,
(paperback) 2007
Remarkable Creatures: Epic Adventures in the Search for the Origins of Species, 2009

Lynn Helena Caporale:
Darwin in the Genome: Molecular Strategies in Biological Evolution, 2002

SEM (scanning electron microscope) photograph of eyes replacing antenna in a fruit fly by Naoum
Salame. http://1tv4.sl.pt

Fly Eye Genetics:
http://www.pbs.org/wgbh/evolution/library/04/4/text_pop/l_044_01.html
Renowned scientist Dr. Walter Gehring discusses master control genes and the evolution 
of the eye.

Darwin, 1859, The Origin of Species, http://darwin-online.org.uk/contents.html. In most editions, the quote appears on pp143-4.

The gift that keeps on giving: Darwin and the Origin of Species

Published by on in Science
Reply

In conjunction with Darwin2009 Houston, a year-long celebration of Darwin’s 200th birthday and 150th anniversary of the publication of “On the Origin of Species,” HMNS will host a series of events exploring the contributions of this famous scientist.

Today’s guest blogger is Francisco J. Ayala, who shares some his findings here prior to his Feb. 24 lecture at the Museum, on “Darwin’s Gift to Science and Religion,” a part of HMNS’ Distinguished Lecture series.

The Origin of Species #1
Creative Commons License photo credit: gds

Darwin occupies an exalted place in the history of Western thought, deservedly receiving credit for the theory of evolution. In The Origin of Species, he laid out the evidence demonstrating the evolution of organisms.  However, Darwin accomplished something much more important than demonstrating evolution. Indeed, accumulating evidence for common descent with diversification may very well have been a subsidiary objective of Darwin’s masterpiece.  Darwin’s Origin of Species is, first and foremost, a sustained argument to solve the problem of how to account scientifically for the design of organisms. Darwin seeks to explain the design of organisms, their complexity, diversity, and marvelous contrivances as the result of natural processes. Darwin brings about the evidence for evolution because evolution is a necessary consequence of his theory of design.

The advances of physical science brought about by the Copernican Revolution had driven mankind’s conception of the universe to a split-personality state of affairs, which persisted well into the mid-nineteenth century.  Scientific explanations, derived from natural laws, dominated the world of nonliving matter, on the Earth as well as in the heavens.  Supernatural explanations, which depended on the unfathomable deeds of the Creator, were accepted as explanations of the origin and configuration of living creatures. Authors, such as William Paley in his Natural Theology of 1802, had developed the “argument from design,” the notion that the complex design of organisms could not have come about by chance, or by the mechanical laws of physics, chemistry, and astronomy, but was rather accomplished by an Omnipotent Deity, just as the complexity of a watch, designed to tell time, was accomplished by an intelligent watchmaker.

It was Darwin’s genius to resolve this conceptual schizophrenia.  Darwin completed the Copernican Revolution by drawing out for biology the notion of nature as a lawful system of matter in motion that human reason can explain without recourse to supernatural agencies. Darwin’s greatest accomplishment was to show that the complex organization and functionality of living beings can be explained as the result of a natural process—natural selection—without any need to resort to a Creator or other external agent.  The origin and adaptations of organisms in their profusion and wondrous variations were thus brought into the realm of science.

crab on the rocks
Creative Commons License photo credit: angela7dreams

Evolution can be seen as a two-step process. First, hereditary variation arises by mutation; second, selection occurs by which useful variations increase in frequency and those that are less useful or injurious are eliminated over the generations. “Useful” and “injurious” are terms used by Darwin in his definition of natural selection. The significant point is that individuals having useful variations “would have the best chance of surviving and procreating their kind.” As a consequence, useful variations increase in frequency over the generations, at the expense of those that are less useful or injurious.

Natural selection is much more than a “purifying” process, for it is able to generate novelty by increasing the probability of otherwise extremely improbable genetic combinations.  Natural selection in combination with mutation becomes, in this respect, a creative process.  Moreover, it is a process that has been occurring for many millions of years, in many different evolutionary lineages and a multitude of species, each consisting of a large number of individuals. Evolution by mutation and natural selection has produced the enormous diversity of the living world with its wondrous adaptations.

Francisco J. Ayala is a noted biologist and philosopher at the University of California at Irvine’s Department of Ecology and Evolutionary Biology. Don’t miss his lecture on Feb. 24 – or any of the other Darwin2009 events planned at HMNS this year.