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Hey Folks!


The co-evolutionary issue at hand today has quite the Aussie spirit to it. This is a story about the coevolution of Australia's wildlife, particularly kangaroos, with a changing environment due to humans.

Aboriginals have been using brush fires as a form of hunting for thousands of years, to capture lizards in the winter. Scientists believe that these practices lead to the success of some animals over others. For example, the small fires burned down the grass, and exposed the small patches of land to more easily spot lizard mounds and other prey for foragers.

Over time, species evolved to adapt and even become dependent on the small fires that the aboriginals used. The patches left by burning left areas of old and new vegetation, which benefitted species like kangaroos, that could hide from predators in the old vegetation and use new growth patches as a food source. The kangaroo populations actually decline in areas outside the areas affected by human fire.

These ecological benefits of the fires set by Martu peoples highlights what might be an unintentional sustainable practice. Although setting the grasslands on fire may sound like the opposite of helping an ecosystem, the blazes are smaller than those caused naturally by lightning, and the controlled fires may actually prevent massive destructive fires from sweeping over a larger area.

Australia has been seeing a decline of mammals, and it may be due to a removal of practices like the aboriginal burning regimes and other human intervention, such as introduced species. The reinstallation of these fires might be able to save several species of animals native to this habitat and adapted to the occasional small fires.

This is a story of removing an element that one species has coevolved to. When a rapid change occurs  (like removing the fire mosaic), the small, fire-adapted mammals are exposed to different conditions, that put pressure on their life habits and expose them to dangers like large widespread bush fires.



Thanks for reading today!

Can you think of any other instances in which animals coevolved to a human activity that was eventually stopped? Let me know in the comments below!


Thanks and have a great day!


D



Resource:

Codding, B. F., Bird, R. B., Kauhanen, P. G., & Bird, D. W. (2014). Conservation or Co-evolution? Intermediate Levels of Aboriginal Burning and Hunting Have Positive Effects on Kangaroo Populations in Western Australia. Human Ecology, 42(5), 659-669.

Happy Easter,  Folks!



 So far, we've covered two types of coevolution. Predator and prey, as with the snake and lizard, and host and symbiont, as with the wolves & humans. Today, we will discuss a third type: host and parasite evolution.

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Host-parasite coevolution refers to complementary genetic change of two opponents driven by mutual selective pressure. Both species are constantly trying to get the better of each other, but reciprocal adaptations make it almost impossible for one side to get the upper hand.

Host-parasite evolution is important across a range of fields including wildlife ecology and agriculture. but perhaps one of its most outstanding features, is that it is opening a door to studying disease in the medical field.

Many fatal human diseases like influenza, AIDs, and malaria have been known to be constantly evolving, and thereby evading the treatments or vaccinations against them. Scientists want to further understand the intricacies of the interactions of diseases with the human immune system and their coevolution patterns to be able to make effective more effective treatment and perhaps an innovative solution to protect human lives.

The problem is that studying and validating coevolution with disease is a difficult thing to do. Demonstrating co-evolution is difficult because the world of science has inadequate "understanding of either the genetics or molecular basis of the host–pathogen interaction; involve-ment of polygenic traits; fitness constraints on these traits, including constraints imposed by simultaneous interactions with multiple hosts or multiple pathogens; phenotypic plasticity; and the long time scales involved" (Woodhouse et al 2002). So what are the solutions? Find concrete evidence of human-pathogen coevolution, of course. But to do this there need to be new modern approaches to how we search for  and detect coevolution. Woodhouse et al suggests that one way to do this is to look to the molecules for clues. That is, search for changes in each species' genes that are involved in interaction between the two. Reciprocal polymorphisms in the genes could provide evidence that the host and pathogen are coevolving and reacting to the other's adaptations over time. 

I brought this to you readers because I am interested to know...

 Do you think humans can "win" over pathogens by science and wit alone? 

Will understanding the interactive foundations of host and pathogen and consequent adaptations be a savior? What will this mean for the future of medicine or pathology?

Do medical "solutions" just drive disease to evolve faster and become more dangerous?


Overall, I think that our understanding needs to be deeper in this matter if we want to help save more lives in the present. That said, I'm not sure if humans are tempting nature or fate by trying to win an evolutionary battle thats been raging for thousands of years. Falsely thinking we have rid the world of a disease could make us more susceptible to an adaptation or mutation in the disease in the future. There is no doubt that there are some incredible medical innovations waiting to be invented.


Thanks for reading and comment below what YOU think on the matter. 

Have a great week,  

D

 

Reference:

Woolhouse, M. E., Webster, J. P., Domingo, E., Charlesworth, B., & Levin, B. R. (2002). Biological and biomedical implications of the co-evolution of pathogens and their hosts. Nature genetics, 32(4), 569-577.