BIOL 116 Template 2024

Introduction

The transition from surface streams to the perpetual darkness of underwater caves has driven remarkable evolutionary changes in the Mexican blind cavefish (Astyanax mexicanus). Within the past few million years, populations migrating into caves abandoned their functional visual systems, a trait retained by their stream-dwelling counterparts. This dramatic adaptation is not unique to cavefish; troglobitic animals, including crustaceans, insects, salamanders, and spiders, have independently evolved similar traits, such as eye degeneration and heightened reliance on non-visual sensory systems.

Globally, over a hundred species of cave-dwelling fish exhibit varying degrees of blindness and other cave-specific adaptations, such as reduced pigmentation and enhanced mechanosensory abilities. The Mexican blind cavefish serves as a model organism for exploring how extreme habitats shape life through genetic, ecological, and microbiological influence

Biological evolution is often framed as a process of innovation, with emphasis placed on the development of new traits such as the legs of amphibians, the hair and mammary glands of mammals, or the large and complex brains of higher primates. However, this perspective overlooks an equally important evolutionary phenomenon: regressive evolution, or the loss of structures and traits that are no longer advantageous in a given environment. In many cases, evolutionary progress entails trade-offs. For a newly developed trait, an organism’s ancestors may have lost features that were no longer critical for survival. For instance, amphibians sacrificed the gills, scales, and tails that were essential to their aquatic ancestors, adapting instead to a terrestrial lifestyle. Blind cavefish exemplify regressive evolution through their loss of functional eyes and pigmentation. Living in absolute darkness, vision itself offers no survival advantage, while maintaining eyes and pigmentation would demand considerable metabolic energy. Natural selection, therefore, favors the loss of these structures. This evolutionary process illustrates that regressive changes are not failures of evolution but rather strategic responses to environmental pressures.

Figure 1. Electron micrograph of the Ebola Zaire virus. This was the first photo ever taken of the virus, on 10/13/1976. By Dr. F.A. Murphy, now at U.C. Davis, then at the CDC.[1].

At right is a sample image insertion. It works for any image uploaded anywhere to MicrobeWiki. The insertion code consists of:
Double brackets: [[
Filename: PHIL_1181_lores.jpg
Thumbnail status: |thumb|
Pixel size: |300px|
Placement on page: |right|
Legend/credit: Electron micrograph of the Ebola Zaire virus. This was the first photo ever taken of the virus, on 10/13/1976. By Dr. F.A. Murphy, now at U.C. Davis, then at the CDC.
Closed double brackets: ]]

Other examples:
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Subscript: H₂O
Superscript: Fe³⁺

Section 1 Genetics

Section titles are optional.
Include some current research, with at least one image. Call out each figure by number (Fig. 1).

Sample citations:

A citation code consists of a hyperlinked reference within "ref" begin and end codes.

For multiple use of the same inline citation or footnote, you can use the named references feature, choosing a name to identify the inline citation, and typing

Second citation of Ref 1:

Here we cite April Murphy's paper on microbiomes of the Kokosing river.

Section 2 Microbiome

Include some current research, with a second image.

Here we cite Murphy's microbiome research again.

Conclusion

You may have a short concluding section. Overall, cite at least 5 references under References section.

References

Edited by [Isaac Turnley], student of Joan Slonczewski for BIOL 116, 2024, Kenyon College.