Speciation and Evolution of Cichlids in East Africa
Dr. Hoeh WIC
Matthew S. Holcomb
March 2, 2015 Introduction
The East-African cichlids are a rather interesting and diverse group of fish, and have caught the eye of many scientists particularly because of the speed, diversity, and convergent patterns of their radiation (Yong-Hwee et al. 2012). For instance, there are 500+ species in just one lake, Lake Victoria, and an estimated 2,000+ species in total. The fish in lake Victoria, which is estimated to be 100,000-400,000 years old or less and to have suffered a complete drought only 14,600 years ago, are an amazing example of just how quickly these fish have diversified (Rijssel et al. 2014). And on an evolutionary time scale, 14,600
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2009). And also, as can be seen from the figure below, Schwarzer and his team were able to determine that the ancestral lineage of the EAR’s have spread from the lakes in Central Africa. However their research does not determine how the EAR’s came into existence. Figure 1: Consensus BI Tree of the African Cichlid Phylogeny.
Consensus tree (50% majority rule) of the African cichlid phylogeny based on the concatenated dataset. The dataset comprises mitochondrial and nuclear sequences of nine independent markers. Green numbers at nodes refer to bootstrap-values (BS, 1000 replicates) of the ML run and black numbers to Bayesian poste- rior probabilities (BPP). Filled circles represent a 100% BS support and 1.00 BPP and empty circles 1.00 BPP and lower BS val- ues. Major groups within the phylogeny were named based on either their center of geographic distribution (Austrotilapiini and Boreotilapiini) or based on taxonomic aspects (Oreochromini). The asterisk (*) in the tree marks the type species of the genus Tilapia. The leaf stability index exceeded 0.95 for all specimens, except for clade AI (all taxa 0.90). Note that for clade AI only representatives of the EAR are included. The results presented here were verified using a more detailed taxon sampling based on ND2 (see additional file 3). The map in
Over the last several years, evolution has been playing an increasingly important role in determining how various species are evolving. This is because ecology will have an impact on how quickly a particular organism is able to adapt (with: the unique challenges for a particular environment). To determine the effect that this is having requires carefully examining different species over the course of many years. This will be accomplished by comparing these changes on Darwin and Wallace Islands. Once this occurs, is when specific insights will be provided that are highlighting the underlying challenges affecting the development of organisms. This is the point that these transformations will be evident among the various life forms. (Fasolo, 2011, pp. 53 68)
1. Neil Shubin, author of Your Inner Fish, and his colleagues travel to Ellesmere Island to look for and study the shift from fish living in water to creatures living on land (4). Fossils from 360 million years ago include amphibians and reptiles. Fossils 385 million years old, only fish are found. Because of this, Shubin and his colleagues look at the time in the middle of this, 375 million years ago (10). In 2004, they give it another try, after failed previous tries (21). What gradually emerges from the rocks they searched for in the bottom of the quarry is an “intermediate” right between fish and land animals, Tiktaalik, “large freshwater fish” (22-25).
As seen with Anolis, single species of organisms have the ability to undergo adaptive radiation and become new species by filling niches in a given environment. This is prevalent not only in Anolis, but other model organisms as well, such as finches, sticklebacks, and cichlids. All of these organisms have gone through the similar mechanisms and processes to evolve into different species. Alike to Anolis, they have gone through reproductive isolation, adaptation, and convergent evolution. Due to a poor fossil record of Anolis, the other model organisms may give better outlook on how they have diverged overtime. Further investigations on all of these organisms and their evolutionary mechanisms would not only give better a better idea of ecological speciation, but more comprehension on the origin of all
In the marine lab, there is a Texas Cichlid named Kevin or Texas Toast. It is also known as “Herichthys cyanoguttatu” (Sharpe, William). It was brought to Europe in 1912 and it’s the only cichlid that is found in the United States (Sharpe, William). The Texas cichlid is now in the northern part of Texas to Florida mostly due to people getting rid of the fish because they don’t want to take care of it anymore (Sharpe, William). It is a favorite fish to catch (Sharpe, William). The Texas cichlid is normally in the lower portion of the Rio Grande Drainage (Berg, William).
Evolution is one of the most important factors when looking at history. A crucial moment in evolutionary process is speciation. Fortunately, we have the fossil record of a transitional species called tiktaalik. Tiktaalik was the transitional species of sea creature that would evolve into a land creature. It was found on Ellesmere Island in the Canadian arctic and is believed to be around 383 million years old (Class Lecture).
The Chrysalids by John Wyndham is a science fiction novel that sets place in the future long after a nuclear holocaust has devastated large areas of the world. The stories focal point is on the people in a group of highly intellectual people that are compelled to leave and go to the story calls “The Fringes”. This is a place where people who do not fit God’s true image go. What this means is, is if you have any type of deviation, you will be considered abnormal. The novel is written in first person and told by the character David Strorm. David is one of the advanced children. The story takes the reader through David’s life and the things that happen in his life throughout the entire course of the novel. The Chrysalids expresses the precise
In the case of ring species, natural selection and sexual selection each play a role in the divergence of ring species. Selective pressures allowed one phenotype to survive better than others in a certain area; sexual selection could cause divergence because organisms choose mates based on phenotypes. In the case of salamanders, natural selection affected divergence because organisms with certain coloration survived better in coastal or inland environments. In warblers, sexual selection and natural selection seem to play a part in the divergence of the ring species, as forest density and migration distance is variable and affects survival of the species. Molecular and morphological evidence can be used to support multiple species by showing
“In the 1950s the Nile Perch was introduced into Lake Victoria to boost the fishing community.” (National Geographic Society, 2015) But when introducing this fish into the lake it came with positive and negative effects. On the positive side, it created an economic boom. For negative effects, it caused the near extinction of a native fish known as the Cichlid (National Geographic Society, 2015). As far as the Cichlids becoming nearly extinct when this unusual fish entered their native home they were not prepared to defend themselves from this fish they had never encountered before (National Geographic Society, 2015). Soon after the cichlids were becoming extinct they were being overly fished and the Nile perch was running out of food resources and the Nile Perch population would soon decline ( National Geographic Society, 2015).
The Out-Africa-Theory that has been heavily sided with is the hypothesis that remains the most likely to have happened. Not only because that is the theory that has the most scientific evidence but also because that is were the remains of the oldest primate fossil on all seven continents have been found. Even though the recent evidence in Asia is very convincing, there is too much noteworthy evidence found in Africa that an not be ignored. Moreover, such a new theory is lacking a substantial amount of evidence and investigation in order for it to become convincing theory. This leads the scientific world to side with the fact that we have deeper-rooted ancestry in Africa.
I am a Spanish major and double minor in Linguistics and French, and have focused my linguistics study on language in literature, conversations, music and social perspectives. I am seeking a teaching assistantship for the 2016-2017 academic year. In addition, through my university’s McNair Scholars Program and with the guidance of Angela Vidal Rodriquez-Vidal, I have explored an interdisciplinary study of Latin America and Spain, focusing on their history, culture, politics and Language. This course of study sparked my interests in semantics and syntax of the Spanish language, which was further bolstered by my internship with Michigan State. I hope to continue on this venture by obtaining a Teaching Assistant position.
A product that I have purchased recently is new tires for my car. I purchased four Michelin Defender tires in the retail store Discount Tire in Knightdale, NC we offer a wide selection of leading tire brands along with Discount Tire exclusive brands such as Arizonian, Road Hugger, Pathfinder and MB Wheels. Michelin is one of the best tires brand in Europe and North America. Also, the Defender version has an impressive 90,000 mile warranty.
The type of food cichlids require is another way this breed differs from each other. It is thought to be one of the reasons they are as widespread and successful as a species. Some eat algae and vegetation, while others eat other fish and snails. Also, some are highly aggressive and territorial, while others are shy and timid. The aggressive, fish eating species have often proved troublesome for uninformed aquarium
Evolution occurs when an animal species develops new bodily structures and functions in order to adapt to their new environment. These developments are seen as positive adaptations that enhances survival. However, some animal species have lost these new developments. Based on the geographic location and climate, some evolutionary developments that are no longer needed are lost due to the fact that the new bodily structure itself does not enhance the chance of survival in a particular environment (Kirchman 2009; Vieites, et al. 2009). In most cases these lost developments are passed down through future generations and are never redeveloped. However, more information is needed to decide whether or not the loss of these evolutionary developments was due to natural selection or by random mutation over years (Wilkens and Strecker 2003). In this paper, I will examine three studies from a diversity of taxa, which illustrate the history of flightless birds, how climate has influenced the evolution of salamanders and how life lived in darkness has influenced the blindness in cave fish. Together these studies depict how these evolutionary abilities are lost and their affects on the animal species.
In Macbeth, the two characters ultimately responsible for the murder of King Duncan are Macbeth and Lady Macbeth. The concoct the plan and carry it out in order to ascend to the throne. They are equally responsible for the murder. However, their plan relied on the prophecy Macbeth received from three witches: that he would be king regardless of what actions anyone took. While the witches are not directly responsible Duncan’s murder, their proclamation prompted Macbeth into taking action. How accountable are Macbeth, Lady Macbeth, and the witches in the plot to kill Duncan? They each have their own role in the scheme, some characters having a more direct connection.
The Out of Africa Theory is a widely renown theory describing the origin of the human race and their early dispersal throughout the world. According to this theory, humans have a monogensis, or a single and common origin; Africa. The concept was first introduced in 1871 by Charles Darwin but was deliberated for years until further studies of mitochondrial DNA and evidence ”based on physical anthropology of archaic specimens” was added.