Filtering by Tag: Evolution

What the Fish? Episode 16: Youth Design Team

So, how did you get your jobs?

Becoming a scientist or working in science is never a straight forward path: appreciation of the natural world, hobbies, high school jobs, science fiction and random life events all come into play. We discuss these sinuous paths into science with a special live audience, The Field Museum's Youth Design Team summer interns.  We hope that our stories were a source of science and fishy inspiration!

Youth Design Team

The Youth Design Team (YDT) is part of the TakeThe Field programs here at the Museum and is designed in collaboration with the Pearson Foundation's New Learning Institute. YDT takes teens behind the scenes to interact with scientists, designers, media producers, researchers and other teen volunteers like themselves. Teens hear firsthand what it is like to roam the plains of Africa and tromp through the forests of South America. In addition, they participate in the process of designing an exhibit from scratch!

What the Fish? Episode 15: Exploring Collection-Based Research

Episode 15: Exploring Collection-Based Research

In our last episode, we discussed the role of collection data for scientific investigation. In this episode, we explore the value of the research on museum specimens and artifacts themselves, focusing on the use of specimen examination and evolutionary hypotheses to better explain the natural world. To help us discuss this topic, we are pleased to be joined by Dr. Peter Makovicky, The Field Museum's own Curator of Dinosaurs and Chair of the Department of Geology. Phylogenies (a hypothesis of how life is related evolutionarily) are crucial for predicting the distribution of incompletely studied organismal characteristics ranging from the presence of venom in fishes, to feathers on dinosaurs, or how the anatomy of eyes change in the deep sea as a result of selective pressures. In other words, knowledge of the evolutionary relationships of life allows for effective predictions about the unstudied characteristics of species. Museum collections are a critical component of this work, from the initial collection of samples used to infer our hypotheses of how life is related (e.g., whole specimens, tissues used to extract DNA for genetic work) to our ability of accessing this material again to test and explore evolutionary hypotheses.

An example of the biological questions we can explore in this manner is tracing the evolution of venomous fishes. By looking at venomous fishes from an evolutionary perspective, we generated a much more accurate picture of fish venom evolution than was previously suggested using a strictly observational approach. To explore venom evolution, we began by taking a major stab at the fish tree of life by analyzing all suborders and known venomous groups of spiny-rayed (Acanthomorpha) fishes for the first time. Using the resulting family tree of fishes as a framework, we mapped the species that were known to be venomous on to this DNA-based tree. This provided an initial estimate of how many times venom evolved and allowed us to predict which fish species beyond the "knowns" should be venomous or could possibly be venomous. To test these predictions, we explored the museum collections and dissected scores of specimens to look at the detailed anatomy of fish venom glands and clarify how many times venom evolved on the fish tree of life. By working our way down the fish tree of life by comparing ever more distantly related fishes from the known venomous fishes, we could pinpoint the number of times venom evolved, the exact groups of fishes that are venomous, and revise the identity of venomous fishes. This type of research is occurring world wide based on the collections at The Field Museum, and similar institutions that house, maintain, and allow access to museum specimens for scientific research. This example is just one of the many stories surrounding research done at The Field Museum with collection-based research.

What the Fish? Episode 14: The Value and Role of Collection Data

Field Museum Collection Data

In previous What the Fish? podcasts, we have covered topics ranging from what makes a fish a fish to aquatic bioluminescence and sensory systems.  We have augmented these fishy topics with discussions surrounding the role scientists play in developing content for museum exhibits and the excitement, hardships, and discoveries made during fieldwork.  Herein, we present the first part of our What the Fish? collections-based research episodes exploring the value and role of Museum collections and their associated data in scientific investigation. To help us discuss the topic of the analysis of collections data, we are joined by Hannah Owens who is a doctoral candidate at The University of Kansas. Hannah combines museum collections data, fisheries data, and ecological data to explore the role of climate change in the evolutionary history and the biogeography of fishes. Hannah's research combines ecological niche, macroevolution, and climate data to explore the "fish stick" fishes or cods, hakes, and relatives from the order Gadiformes.  

What are collection data, and why are they useful?

When ichthyologists conduct their fieldwork, they collect much more than the specimens themselves.  Fish biologists minimally collect geographic (e.g., latitude and longitude) and temporal (date and time) data, but they frequently collect habitat information, depth, salinity, temperature, visibility, and a wealth of other ecological data that are databased along with the specimen identification and information in databases such as those at The Field Museum.  Individually, these records are valuable for ichthyologists interested in the distribution or biogeography of particular species, but when taken in aggregate (e.g., through pooled resources such as GBIF) these data can be explored in "meta-analysis" that can inform countless ecological and evolutionary studies. For example, predictive modeling of organismal distributions has brought these data together to better predict the expansion of introduced species, to predict the potential presence of animals or plants in unexplored regions, and to test for the impacts of climate change. These predictions and analyses are only going to become more critical as species continue to be introduced, species distributions continue to shrink toward extinction, fieldwork becomes more difficult, or large-scale climate change becomes increasingly studied. These collection data, based on well-curated specimens, are the only verifiable data that can be brought to bear on these questions. Distributional data that lack preserved specimens (vouchers) can always be questioned at a later date because the species identifications cannot be reassessed. This same value in being able to reassess species identifications based on whole-specimen vouchers is equally important for genetic or DNA-based research where the discovery of cryptic species (morphologically similar species representing  diagnosable and genetically different forms) is a frequent occurrence.  In cases where there are no voucher specimens to examine, researchers are required to return to the field to corroborate their molecular hypotheses.  These are just a few of the cases where specimens and their associated data have contributions well beyond ecology and evolutionary biology.  Listen to the podcast to learn additional examples! 

What the Fish? Episode 13: Exploring Fish Evolution on the Tree of Life

Piecing Together the Mysteries of the Fish Tree of Life

One of the primary reasons that we here at What the Fish? are fascinated with the evolutionary history of life on Earth is that it provides a context and scientific hypothesis from which we can further study the wonderful biodiversity of fishes. For example, if we have a working scientific hypothesis of how different species of clownfishes are related to one another, we can address questions surronding the number of times clownfishes have formed symbiotic relationships with anemones. But how do we build these evolutionary trees of fishes, such as the one seen below? Well there are various different kinds of scientific data that can be used to infer evolutionary relationships through time (e.g. variation in the sequence of DNA/genes, anatomical features, behavioral traits) that scientists around the world collect in order to support these hypotheses. Shared anatomical characteristics, such as the position of a spiny-rayed dorsal fin, may be indicative of common evolutionary ancestry, and scientists use this evidence to produce hypotheses regarding the evolution of life on Earth.

What the Fish? Episode 12: A Fish in Shining Armor

A Fish Can Be Encased in Armor?

Although they vary in size, morphology, and type (e.g., plates, scutes), many fishes have evolved thick armor-like scales that help protect them from their aquatic environment and potential predators. Many fishes that live in and around the bed of aquatic environments utilize armor to protect their bodies from loosing scales as they burrow and scrape along rough substrates and potentially rocky or jagged environments, such as catfishes and poachers. Other armored fishes may sacrifice mobility for a tank-like body that makes them nearly inedible to nearby predators. For example, the aptly named boxfishes have scales are hexagonal in shape and result in an armor that looks like a bee's honeycomb. The body armor of fishes are so effective that various scientists and researchers have been investigating the morphological properties of fish scales, such as those in bichirs, to aid with the development of stronger body armor for humans!

What the Fish? Episode 11: Feeding Frenzy

You Are What You Eat

Among fishes, the different types of food and the ways in which they are consumed are as incredibly varied as the fishes themselves. Some fishes are vegetarians, including the Piranha relative the Pacu, while others are ferocious carnivores, such as the African Tiger Fish. Fishes often have very specilized dentition and feeding structures depending on their source of food. For example, fishes that crush hard crustacean shells may have large boulder-like teeth. Filter feeding fishes, such as the Whale Shark seen below, have evolved fine filamentous structures to help sift through plankton. Overall, fishes eat almost anything you might find in an aquatic environment, and they do so efficiently!

Episode 10: Fishy Tales of Terror

In the deep, no one can hear you scream

The vast expanse of the seas is our destination, and uncontrollable terror is our goal. Join us as we descend into the madness that only total darkness can bring. The deep holds many secrets, and we shall share them with you...including inspirations for sea serpents (Oarfishes - including the photo here taken by our own Leo Smith), fierce predators that hide behind shimmering lights (Anglerfishes), and even the secrets to zombification (Pufferfishes). Caution, don't try zombification at home. Seriously, we don't recommend it. We hope you enjoy our special Halloween and spooky season podcast!


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