Showing posts with label Evolutionary Biology. Show all posts
Showing posts with label Evolutionary Biology. Show all posts

Friday, March 21, 2014

Herpetology: Study Materials on Amphibians and Reptiles

Panther Chameleon (Furcifer pardalis), endemic to Madagascar.
Image courtesy link
-by Aaron S. Johnson

Introduction:

Herpetology is the zoological study of amphibians (frogs, toads, salamanders, newts, caecilians [legless amphibians]) and reptiles (turtles/tortoises, snakes, lizards, amphisbaenians [non-snake, legless squamate clade], crocodilians, tuataras).  A herpetologist is an expert in amphibian and reptile behavior, diet, ecology, taxonomy, physiology, anatomy, evolution, health, conservation, and husbandry.

Amphibians have been around for over 370 million years (m.y.) and reptiles for 310-320 m.y.  Amphibians are the descendants of a fishlike ancestor, whereas reptiles descended from a common amphibianlike ancestor.  Together, reptiles and amphibians are collectively known as "herps" and are the common ancestors of birds and mammals.  


Herps may be ectotherms, but they are voracious eaters of everything humans consider as "pests" and carriers of disease, e.g. insects, arachnids, slugs, rodents.  Needless to say, world ecological systems would collapse without them.  With the decline of amphibians and reptiles due to herbicides, pesticides, pet trade, destruction of the environment, climate change, invasive species, and pathogenic microbes, the importance of these creatures have grown ever more apparent.  Accordingly, modern herpetologists should have expertise in microbiology, chemistry, climatology, conservation, and even business administration, communications, and sociology in order to professionally problem solve as difficult issues arise. 


Tuesday, March 11, 2014

Study Materials on Evolutionary Biology


This Great Tree of Life diagram is based primarily on the evolutionary relationships so wonderfully related in Dr. Richard Dawkins' The Ancestor's Tale. The smallest branches are purely illustrative; they are intended to suggest the effect of mass extinctions on diversity, and, on a few of the branches, changes in diversity through time. The diagram mainly tries to illustrate a great lesson of evolution; that we are related not only to every living thing, but also to every thing that has ever lived.