BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: ecology

Big Cat, Little Bird

A fishing cat in a bird's nest

Credits: Allama Shibli Sadik & Muntasir Akash / De Gruyter

 

Cats don’t hate water, contrary to popular belief. In fact, there is a species of wildcat evolved to hunt in water. 

Aptly named “fishing cats,” Prionailurus viverrinus is a species of South Asian cat that has evolved to fish. Unlike other felines, they have slightly webbed forepaws and double layered water-resistant fur. This gives them an edge over others as it means they won’t freeze when they fish, giving them an opportunity to pass this trait down and allows them to stay reliant on their fishing diet, unlike other cats who primarily rely on land prey. They are medium sized cats with yellowish fur, and black tabby stripes that gradiate into mottled spots.

They catch their prey by idling on the edge of a body of water, and scooping the fish out of the water. Very rarely do they wade in and put their head underwater to fish.

But their diet does not solely consist of fish. They are also known to eat small rodents, lizards, amphibians and birds in addition to fish.

The only problem is that with the monsoon season, it is nearly impossible to fish as the land prey is gone, and their usual waters are flooded or destroyed. These cats live in areas prone to flooding and the lack of infrastructure means that the prey cannot flee (also fish cannot sustain on land).

So what does the brilliant cat do?

It climbs trees and preys upon the bird colonies. It has been seen preying upon waterbirds (ie. herons, moorhens, cormorants) high within the tree canopy, snapshotted with camera traps.

This might just be its secret to success since the local population also relies on the fish and (since people have more power than these felines) will deter (and kill) these cats. These waterbirds are not just the cats’ benefit, but the benefit of the locals as well!

Unfortunately, due to brackish waters and the urbanization of wetlands, the clever species is slowly dying out. But that’s another article.

There isn’t a lot known about these guys, but there are ongoing research projects with them.

Spotlight: Sharon Strauss and Evolution of Organisms in Barren Habitats

Sharon Strauss is an evolutionary ecologist at the University of California, Davis (UC Davis) where she has been conducting research on the evolution of plants and the ways in which they interact with other species. As a woman in a STEM environment, Strauss has faced opposition due to her gender. It took her 5 years longer than the regular time trajectory to obtain a job in her field, subtle obstacles such as invitations to work with groups, and also simply not being taken seriously or personally asked to contribute to group conversations. Although she has faced challenges, Strauss has done phenomenal research on the ecology and evolution of plants and her efforts, both her research and her job as a professor, have been rewarded.

One of her largest and most well known projects was called Nowhere to run, nowhere to hide. During this project, she and her team were studying how wildlife adapted to a barren environment. During this expedition, Strauss and her team explored the possible connection between attack rates and visibility. They followed 160 seedlings of a few different species from the genus Streptanthus and observed how they grew and what their current condition was depending on the amount of bare ground and leaf coloration. Additionally, they formed small clay models of caterpillars to act as an undefended population of prey in order to measure attack rates on visible animal species. They measured this by checking the area around the caterpillars to see if there were beak or tooth marks of a predator attempting to eat it. Strauss was able to conclude that attacks on both animals and plants were connected to how apparent or visible they were in their environment. For this reason, certain plants and animals had adapted by changing their color in order to blend into their barren environment.

Since this project mainly involved studying adaption and evolution, it is not very similar to anything we have learned in class yet. However, there is a connection between evolution and genes, which we are currently learning about. Every organism that sexually reproduces passes genes down to their offspring via the sperm and the egg. The physical features of the offspring are determined by the genes they are composed of. Typically, these genes are passed down by the parents to the offspring; however, it is also possible for an error in DNA replication to occur or exposure to chemical or radiation damage that can cause a mutation. This connects to evolution since there will always be variety within a population. A certain trait could prove to be more successful in survival than another so gradually, over many generations, that trait will be passed down since the members of the population that have that gene have a higher chance at surviving and reproducing as proposed in Darwin’s Theory of Evolution.

I admire the hard work and the effort that Sharon Strauss has put into her career and passion to get where she is now and to have achieved what she has. Despite the barriers that were placed in front of her, she continued on since biology was her passion. I also have a passion for biology, specifically zoology, and as a girl, I may face similar obstacles. Even if I change my mind or find a new passion, I hope to carry the same spirit that Sharon Strauss did to push through any barriers that I may face.

Did You Know Plants Can Talk?

 

For thousands of years language has been a crucial part of cultures around the world, and a method unique to humanity of transmitting ideas, thoughts, emotions between us. Language has allowed us to work harmoniously together for our mutual improvement and survival. Recently, however, two researchers, Dr. Kim Valenta and her colleague Omar Nevo, have discovered that plants too, have developed their own unique and intricate method of conveying information to their pollinators; “the easier it is for fruit eaters to identify ripe fruits, the better the chance for both [, the plant and the fruit,] to survive.

The most vivid example of plant communication can be found in Madagascar’s Ranomafana National Park and Uganda’s Kiabale National Park where berry plants have evolved “to match each animal’s sensory capacities, [thus] signal[ing] dinner time in the jungle…” Dr. Valenta and Nevo analyzed the exact colors of each fruit with a spectrometer, and “with a model based on the visual capacities of the seed-dispersing animals, they also determined who was most likely to detect different fruit colors contrasting against an assortment of backgrounds.” The researchers concluded that “the colors of each fruit were optimized against their natural backdrops to meet the demands of the visual systems of their primary seed dispersers,” i.e. pollinators. Thus, red-green color-blind lemurs, in Madagascar were best able to detect the fruit with a blue yellow color scheme and monkeys and apes in Uganda, with tricolor vision like humans, were clearly able to distinguish red berries against a green backdrop.

Also recently discovered was that plants can communicate to their pollinators through scent. Dr. Nevo performed a scent-based study on the lemurs in Madagascar. His team collected various ripe and unripe fruits from all over the jungle of Ranomafana. “He suspected the leumur-eaten fruits would have a greater difference in odor after they ripened than the bird-eaten fruits.” To discover exactly how this scent-based communication worked, Nevo used the “semi-static headspace technique.” From this experiment it was confirmed that “fruits dispersed solely by lemurs produced more chemicals and a greater assortment of compounds upon ripening. It is now known that wild lemurs actually spend quite a lot of time smelling for the vivid difference in odor between ripe and unripe fruits in the jungle.

It is astonishing how plants have evolved over the years to be able to communicate with their pollinators for the betterment and expansion of their species. I would be interested to find out, what other organisms communicate (single cellular, multi-cellular, etc.) and what kind of information they find necessary to convey to others for their survival?

 

 

 

 

The Immaculate Conceptions: Smalltooth Sawfish Experiencing Virgin Births

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From Flickr

Chances are you have never heard of the Smalltooth Sawfish, an endangered species most commonly found off the western cost of Florida. These creatures grow to be as long as 25 feet, but their is more that is impressive about these fish than their shockingly large size. Recent studies have shown that around 3% of Smalltooth reproduce asexually, a virgin birth. This is the first hard evidence that birth of parthenogens, offspring born of asexual reproduction, happens in nature. This speaks to the adaptability of life, scientist Demian Chapman, says that it makes sense that endangered species would be the ones most commonly reproducing asexually, “that life finds a way”. This discovery was made when researchers tagged and sampled DNA from around 190 Sawfish, which lead to the discovery of 7 parthenogens.

Scientist hypothesize that during meiosis, sex cells fused together to form offspring. Incredibly, all seven of the parthenogens are fully healthy and functioning, and seem to be viable sexual partners. This “suggests that parthenogens are not a dead end” that this “extreme form of inbreeding” does not lead to any serious defects. Unfortunately, Smalltooth Sawfish are on the verge of extinction due to human interference in their natural habitat. Although the Sawfish are able to reproduce asexually, the occurrence rate is too small to sustain a viable number of Sawfish to save them from extinction, but raising awareness of the issue could be the key to saving these magnificent creatures.

 

Original Article

Sawfish Extinction

More Examples of Parthenogens in Nature

Bacteria to become a new environmentally safe way to control invasive species?

 

source: http://commons.wikimedia.org/wiki/File:Zebra_mussel_GLERL_3.jpg

zebra mussels attached to a dock

Zebra mussels have, since 1991, become a huge problem in the hudson river. They devour the phytoplankton and disrupt the ecosystem, and, being an invasive species and having no natural predators in the americas, their population has soared uncontrollably. Until recently, Dr. Daniel Malloy has discovered a species of bacteria that is deadly to the shellfish, and to his knowledge, not to any other organism in the ecosystem. This solution might be just what the Hudson river ecosystem needs, a way to eradicate the aggressive zebra mussel without using chemicals that are harmful to the rest of the river’s inhabitants. This idea sprang from the use of the natural pesticide BTI (Bacillus thuringiensis israelensis) to control blackflies. Malloy has discovered a species of  Pseudomonas fluorescens called “Strain CL145A” that had the desired affect on zebra mussels. When ingested, the dead cells of the bacteria, emit a toxin that destroys the digestive tracts of mussels, the live cells, outside of the digestive system have little to no effect. Malloy and his team are working on finding a fresh water strain of the bacteria to start to eradicate invasive mussels in other bodies of water.

sources:

http://www.nytimes.com/2014/02/25/science/science-takes-on-a-silent-invader.html?ref=science

http://www.fish.state.pa.us/pafish/bass_black/smb2006/reebuck.pdf

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