Inverebrate: Scorpions

Blog post 4

Hello again, welcome back evolution of venom. Today’s blog topic will be covering one of the invertebrates that use venom. A recap from last blog: a third theory about how venom evolve by gene duplication and which animal lineages evolved venom (exception of birds).

 

First off, what is an invertebrate? An invertebrate is considered to be an animal without a backbone with scorpions, spiders, insects like bees and wasps, cephalopods, molluscs, and jellyfish (Casewell, 2017).

 

Scorpions
Scorpions belong to the order Scorpionida that is a part of the arachnid’s family which is the same family that spiders come from (The Columbia encyclopedia, 2008). The body of the scorpion is comprised of the prosoma (head), a segmented opisthosoma (body), six appendages on the body, two pedipads (claws), a mesosoma (Tail) and a narrow sting at the end on the tail (The Columbia encyclopedia, 2017).

Venom from the gland is forced down and out of the tip of the stinger by the muscles around the gland (The Columbia encyclopedia, 2008). Scorpion venom affects human differently depending on the species of scorpions as symptoms can occur in five hours including nausea, sweating, and vomiting. As the venom affects the nervous system, more dangerous symptoms are respiratory problems, multi-system-organ failure and death (Petricevich, 2010).

 By Shantanu Kuveskar - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=38768394

 

In next week’s blog, we be covering other invertebrates that use venom. Below are the articles used in this week’s blog if anyone wants to read more about scorpions.

 

References  

Casewell, N. 2017, "Evolution: Gene Co-option Underpins Venom Protein Evolution", CURRENT BIOLOGY, vol. 27, no. 13, pp. R647-R649.

 

Petricevich, V.L. 2010, "Scorpion Venom and the Inflammatory Response", Mediators of Inflammation, vol. 2010, pp. 1-16.

 

scorpion. (2017). In P. Lagasse & Columbia University, The Columbia encyclopedia. (7th ed.). [Online]. New York: Columbia University Press. Available from: https://elibrary.jcu.edu.au/login?url=https://search.credoreference.com/content/topic/scorpion?institutionId=429 [Accessed 30 March 2018].

 

scorpion. (2008). In Philip's encyclopedia. [Online]. London: Philip's. Available from: https://elibrary.jcu.edu.au/login?url=https://search.credoreference.com/content/entry/philipency/scorpion/0?institutionId=429 [Accessed 30 March 2018].

 

Venom Evolution Part 2

Hello again. Welcome back to Evolution of venom. Today blog topic, we will be covering venom evolution part 2. A recap from the last blog: Two theories about venom evolution were covered, positive Darwinian selection and macro evolutionary diversification (biosynthesis and sequestration).

 
Today’s theory about venom evolution is gene duplication. Gene duplication is where a part of the DNA is duplicated and mutates without leaving any harmful consequences to the animal and may increase the fitness of the animal (Fatima, E. 2013). Some of the DNA duplicates may be retained by natural selection or genetic drift while the rest of the duplicates are lost to mutations (Wong and Belov, 2012).

 

Many of the venom toxins may have evolve by ‘birth & death process’ cause by gene evolution and gene duplication, where a gene with a normal ‘physiological’ body protein is duplicate and the duplicate gene is expressed in the venom gland or other venomous tissue (Casewell et al. 2013). Over time venom has evolved in a few animal lineages from invertebrates and vertebrates with the exception of birds (Casewell, N. 2017).

In next week’s blog, we will be covering some of the invertebrates that can use venom. Below are four journal articles if anyone want to read more about gene duplication.

 

References

Casewell, N. 2017, "Evolution: Gene Co-option Underpins Venom Protein Evolution", CURRENT BIOLOGY, vol. 27, no. 13, pp. R647-R649.
 
Casewell, N.R., Wüster, W., Vonk, F.J., Harrison, R.A. & Fry, B.G. 2013, "Complex cocktails: The evolutionary novelty of venoms", Trends in Ecology and Evolution, vol. 28, no. 4, pp. 219-229

 

Fatima, E. 2013, "Venom evolution: Genetic and external factors", Resonance, vol. 18, no. 3, pp. 287-288

 

Wong, E.S.W. & Belov, K. 2012, "Venom evolution through gene duplications", Gene, vol. 496, no. 1, pp. 1-7.

Venom Evolution Part 1

Hello everyone, welcome back to Evolution of venom part one, today’s blog topic about venom evolution. Before we start covering venom evolution, a brief recap: Venom is a toxin produced by an organism’s specialized tissue that is used for predation/defensive purposes.

 

There are a number of theories that argue on how venom has evolved over time, one argument suggests that venom evolved by positive Darwinian selection where prey animals began to evolve a resistance to the predator’s venom, in turn causes the predator’s venom to become more potent to this change (Sunagar, K. & Moran, Y. 2015).

 

Another argument by (Harris, R. & Arbuckle, K. 2016) suggest that venom evolved into two strategies by macro evolutionary diversification called biosynthesis and sequestration. Biosynthesis is when venom is produced by an animal’s specialized glands, while sequestration is where a animal obtains the toxins used for venom from their diet or an environmental source (Harris, R. & Arbuckle, K. 2016).

 

In next week’s blog post, we’ll cover more theories about venom evolution, below are the 2 article used in this post if anyone want to read more about this. 

 

Harris, R. & Arbuckle, K. 2016, "Tempo and Mode of the Evolution of Venom and Poison in Tetrapods", TOXINS, vol. 8, no. 7, pp. 193.

 

Sunagar, K. & Moran, Y. 2015, "The Rise and Fall of an Evolutionary Innovation: Contrasting Strategies of Venom Evolution in Ancient and Young Animals: e1005596", PLoS Genetics, vol. 11, no. 10.

What is venom?

Hi to everyone who is reading this. My name is Stacey and this is a blog on the evolution of venom. This blog will not only cover the evolution of venom, but will also cover what is venom, what animals use venom and what venom can be used for. This first blog is going to cover on what venom is.

First off, what is venom? In order to understand what venom is, we need to understand what a toxin is.

A toxin is a chemical substance that is produced in the body of an organism that has an adverse effect on animals from different species/same species (Kundu et al., 2015).

Venom is a toxin that is produced in an organism by specialized tissue (Kundu, P, 2015) that is delivered by bites, stings, etc. Venom is used for both offensive/predation and defensive purposes in the animal kingdom (Sunagar & Moran, 2015).

In the next week blog post, we be covering on how venom evolve. Below are the 2 article used in this post if anyone want to read more about this. 

References: 

Kundu, P., Venkitachalam, S. & Vidya, T.N.C. 2015, "Why so toxic? Venom evolution in animals", Resonance, vol. 20, no. 7, pp. 617-627.

 
Sunagar, K. & Moran, Y. 2015, "The Rise and Fall of an Evolutionary Innovation: Contrasting Strategies of Venom Evolution in Ancient and Young Animals", PLoS genetics, vol. 11, no. 10, pp. e1005596.