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Transcripts 28–36

Transcripts 1–9 | 10–17 | 19–27 | 28–36

Shorebird

28. Why do some birds have such long beaks and feet?


Dr. Pamela R. Owen
Senior Biodiversity Educator
Podcast 28


Transcript 28

Birds found along the Gulf Coast of Texas show adaptations for life along shorelines. With their long feet, shorebirds walk in shallow water in search of food. Some shorebirds, like the American avocet, have webbing between their toes, others do not. The feet of all shorebirds have widely spaced toes that allow the bird’s weight to be evenly distributed over the foot. This keeps them from sinking into the wet sand. The long, narrow beaks of shorebirds are used to probe into mud and sand to search for a meal of small invertebrate animals. Each species can find food at different depths, depending on the length of their beak.

Diatoms

29. What are diatoms?


Dr. Edward Theriot
Director
Podcast 29


Transcript 29

Hi, I’m Ed Theriot. I’m Director of the Texas Memorial Museum and a professor in Integrative Biology at The University of Texas. My research is on diatoms. Diatoms are single-celled plants. They are unusual because their cell walls are literally made of glass. Their glass walls are very pretty and highly complex in construction. These glass walls can build up in the bottoms of lakes and oceans forming what is called diatomaceous earth. There are literally millions upon millions of the diatom shells in a cubic inch of lake bottom in a place called Yellowstone Lake in Yellowstone National Park. This allowed me to follow the evolution of one species of diatom into another, which occurred immediately after the last Ice Age. It may be the fastest case of evolution ever shown from the fossil record.

Eagle

30. Are eagles protected in Texas?


Dr. Pamela R. Owen
Senior Biodiversity Educator
Podcast 30


Transcript 30

Live and deceased eagles, their parts, eggs and nests are protected not only in Texas, but nationwide. The Bald and Golden Eagle Protection Act was first enacted in 1940 to protect our national symbol, the bald eagle. In 1962 the act was amended to include golden eagles, which were suffering a population decline resulting from uncontrolled shooting and trapping. A few golden eagles are residents of the Panhandle Plains and Trans-Pecos regions of Texas. Many seen in the western half of Texas are seasonal migrants from northern parts of their breeding range, which extends from Alaska southward through western North America into central Mexico. The golden eagle was named for the gold sheen of the feathers on its head and neck. It is the national bird of Mexico. With a wingspan of 6 to 7.5 feet, it is a majestic bird of prey that nests in high places. Females are one-third larger in size than males, and both parents help care for eggs and young.


Sloth

31. Did this sloth climb trees?


Dr. Pamela R. Owen
Senior Biodiversity Educator
Podcast 31


Transcript 31

Sloths are a fascinating and diverse group of mammals with a rich fossil record that dates back 28 million years. Two species of 2-toed sloths and four species of 3-toed sloths currently make their homes in tropical rainforests of Central and South America. Prehistoric sloths were not limited to life in the trees, for there were many forms with different adaptations for locomotion and feeding. Paramylodon harlani is an extinct Pleistocene sloth that unlike the arboreal leaf-eating sloths of today, did not climb trees, and lived in open woodland and plains regions of North America, including Texas. This might not be too surprising, given this sloth’s large body size and estimated weight of 2300 pounds! Paramylodon had large claws on the second and third digits of its hand that were useful not only as defensive weapons, but may have been used to dig up roots and other vegetation, for this sloth had a diet of mixed plants dominated by grasses.

Prehistoric zebra

32. Did prehistoric zebras live in Texas?


Dr. Pamela R. Owen
Senior Biodiversity Educator
Podcast 32


Transcript 32

Equus simplicidens, often called the American “zebra”, was the earliest member of the equid family, which includes the zebras, horses and wild asses of today. It was not the direct ancestor of zebra species living in Africa, but an even older ancestor to both the zebra and wild ass groups. About the size of an Arabian horse, this extinct equid had a narrow skull and features of its teeth that are similar to those of zebras, especially the endangered Grevy’s zebra. Did Equus simplicidens have stripes? Unfortunately, coat colors and patterns do not fossilize, but we can imagine American zebras with stripes on the legs and one down the back – just like many of its living relatives, the wild asses and zebras. This 3.7 million year old skeleton was found in Idaho, but teeth and partial skeletons of American “zebras” have also been found in Crosby and Hudspeth counties in West Texas.


Butterfly

33. What was the first group of animals to develop wings?


Dr. John C. Abbott
Former Curator of Entomology
Podcast 33


Transcript 33

Flight has evolved at least four times, in the insects, pterosaurs, birds, and bats. Insects were the first group of organisms to evolve wings though and they are also the only invertebrates that have evolved flight. The earliest known fossil of a flying insect—a fossil that is 310 million years old, belongs to the stem group of mayflies. These insects achieved powered flight, 90 million years before pterosaurs or “pterodactyls”. Although only four groups of animals have evolved flight, all of the three extant groups are very successful, suggesting that flight is a very successful strategy once evolved. Bats, after rodents, have the most species of any mammalian order, about 20% of all mammalian species. Birds have the most species of any class of terrestrial vertebrates. And insects have more species than all other animal groups combined.

Dragonfly

34. How big did prehistoric dragonflies get?


Dr. John C. Abbott
Former Curator of Entomology
Podcast 34


Transcript 34

Meganeura is a genus of extinct insects from the Carboniferous Period approximately 300 million years ago, which resembled and are related to the present-day dragonflies. With wingspans of more than 28 inches, Meganeura is one of the largest known flying insects. They fed on other insects, and even small amphibians like modern day dragonflies. Controversy has prevailed as to how insects of the Carboniferous Period were able to grow so large. The way oxygen is diffused through the insect's body puts an upper limit on size, which prehistoric insects seem to have well exceeded. It has been proposed that Meganeura was able to grow so large because the atmosphere at that time contained more oxygen than the present day 20%. Not all scientists agree with this hypothesis, but it has recently gained new traction.


Jarred specimens

35. What are these specimens preserved in?


Jessica Rosales Rains
Former Ichthyology Collections Manager
Podcast 35


Transcript 35

All of the jarred specimens on display are in ethanol, which is a type of alcohol. The vast majority of natural history collections use ethanol for long term storage of their fluid, or “wet”  collections. Alcohol as a storage fluid for fish has been in use since at least the beginning of the 18th century.

Burrfish

36. How does a burrfish inflate its body?


Jessica Rosales Rains
Former Ichthyology Collections Manager
Podcast 36


Transcript 36

When a burrfish is threatened, its stretchy skin and rib less skeleton help the fish to ward off potential predators. These fish puff up by filling an extension of their stomach with water using a system called the buccal pump. Imagine inflating your mouth with air then gulping it down into your stomach. It’s like that, but with water. The burrfish can inflate up to 3 times its normal body size, making the fish too large to be eaten by the average predator.