The recent discovery of Tiktaalik roseae in the Canadian Arctic by Neil Shubin, Edward Daeschler and Harvard’s Farish Jenkins is significant in the evolutionary transition of organisms from water to land. Tiktaalik is an extinct lobe-fin fish that evolved during the Devonian period, 375 million years ago. Tiktaalik’s unique features convey their developing adaptation to the amphibians’ habits in the shallow water.
The evolutionary relationship within a group of animal can be established by comparing their physical features and ages. One way to study the relationship between fossils is using the phylogeny, which use the fossil record of the group of organism throughout time to construct a historical sequence. Cladograms can also be used as a way to determine the relations among organisms. Instead of examining when the animal occurred in the fossil record, Cladograms use the components of the animals. In order to organize the relationship among groups, Cladograms uses two types of characters: the primary and secondary characters. Primitive character is the feature of a group of organisms that is inherited from a common ancestor. In order words, an organism must share the same primitive character to be included in the group. Derived or secondary characters are features that are not shared with all organisms in a larger group because they evolve after the primitive character.
From analyzing the fossil evidence, experts have discovered that early tetrapod amphibians evolved from lobe-fin fish. Amphibians are cold-blooded vertebrates animals that live under water and on land. Ichthyostega is considered the first amphibian and land vertebrate. Eusthenopteron is one group of fish that evolved during the Devonian and made a significant...
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...Devonian period influence these fish to use their exaptations to explore a new habitat. This is the Ecological Opportunity hypothesis, which suggest that these fish undergo an adaptive radiation onto the terrestrial environment. This occurs when an environmental change influence the organisms to develop more suitable features and use it under different conditions.
In conclusion, Tiktaalik roseae is a lobe fin fish with traits that shows the gradual process of transitioning from life in water to land. Their structure and unique traits are the evidence that Tiktaalik were relatives of Ichthyostega. Even though they had fins and scale as a fish, Tiktaalik also resemble a tetrapod amphibian with a neck, flat head, skull, ribs, elevated eyes, and air sacs. Therefore, the discovery of Tiktaalik was an improvement that proves how life on land became possible for vertebra.
One hundred and fifty million years ago, large aquatic species of reptile such as the Plesiosaur dominated the ocean, and were pre-eminent predators of the sea. The branch of now extinct Plesiosaurs, or ‘near lizards’, evolved into variant closely related species specialised to take different niches in the food chain. Such species of Plesiosaur include the phenotypically similar Plesiosauroid and Pliosauroid. The physiological adaptations of the long necked variant, the Plesiosauroid, as it relates to deep sea diving, will be addressed in depth.
The relationship of the three species and their ancestors can be summarized by looking at the fossils above. It is evident that all of these three species possess fangs and other types of sharp, prominent teeth. These analogous features indicate that there is some similarity in ancestry, since they all form part of the same family group, although they come from different genus. However, there is some difference in the shape of the head. The coyote possesses a straighter jaw and more angular head. The wolf, on the other side, has a wider denture similar to the fox. These three species also share Homologous structures, such as fangs, are present in these species. Another homologous structure is the legs and ribs, since they all have a similar
The Precambrian Era is when the Earth formed. Earth was barley a spec of dust in outer space and as time went by it gathered ice, rock and more dust particles. It eventually formed into a big rock flying around in space. The Earth was extremely hot and so when it rained the rain would evaporate in mid air or immediately after it hit the ground. But even though it evaporated these great rains cooled the Earth eventually building up water in lower areas creating oceans. The Earths atmosphere was water vapor, carbon dioxide, nitrogen and gases. After awhile oxygen level grew in the atmosphere. The earliest life forms were single celled organisms that lived in the oceans. These organisms used light energy to produce food called photosynthesis. These were called Prokaryotes and Eukaryotes. The evolution of multi celled organisms were Dramatic in change.
Liubicich, D.M., et al. 2009. Knockdown of Parhyale Ultrabithorax recapitulates evolutionary changes in crustacean appendage morphology. PNAS 106 (33): 13892-13896
The origin of modern day whales, a mystery that has puzzled paleontologists for years, may have just been solved with the discovery of an ankle bone. This discovery might sound simple and unimportant, but the bones of these ancient animals hold many unanswered questions and provide solid proof of origin and behavior. The relationship between whales and other animals has proven to be difficult because whales are warm-blooded, like humans, yet they live in the sea. The fact that they are warm-blooded suggests that they are related to some type of land animal. However, the questions of exactly which animal, and how whales evolved from land to water, have remained unanswered until now.
4. Cladistics and evolutionary systematics are two approaches to classification. How are they similar and how are they different? What are the benefits of using one over another?
Acanthostega had a fish-like tail and gills for breathing under water, this being the aquatic part of it. But at the ends of the arms were “peddle-shaped” appendages, thought to be the first “hands” on Earth. Clack’s discovery proved that some fish had arms and legs in the water. It showed that arms and legs were already evolved before organisms started actually living on land, they were used more for survival than walking. In a sense, the “blueprints” of an arm were already in place.
Fortunately, the Axolotl has developed adaptations that aid it in catching food and evading predators. To help it catch food, the Axolotl’s teeth are shaped like cones, so that its “vacuum” action of sucking in as much water in order to also eat food is aided by the shape of the teeth, which allow it to grip, rather than chew. To aid them in avoiding predators they are able to metamorphose so that they use their lungs more than their gill, which allows them to leave very toxic waters and the predators within. Another adaption that helps them deflect any predator is that they are able to regenerate body parts that have been lost, allowing them to stay as strong as possible. Axolotl’s have adaptations that aid their survival from predators in the lake complex Xochimilco that they reside in.
As the novel unfolds, T.C. Boyle’s The Tortilla Curtain reveals underlying racial tensions between white Americans and Mexican immigrants. As the novel shifts between perspectives from both sides, the issue of immigration and the reactions to it become the main focal point. Even when not directly discussing it, the most common symbol used to represent illegal immigrants is the coyote. In The Tortilla Curtain, T.C. Boyle uses a motif of coyote symbolism to reveal the animosity white Americans have toward Mexican immigrants. When coyotes are first introduced in the novel, they immediately show a parallel to Mexican immigrants and the border.
With its abundance of genera, the Burgess Shale is one of the world’s most important fossil fields. It’s discovery in 1909 led to over 100 years of paleontological study in the Canadian Rockies, a majority of which has been carried out in two quarries known as the Walcott and Raymond quarries (Hagadorn, 2002). Though he was originally in search of trilobites in the Burgess Shale Formation, paleontologist Charles Walcott also discovered a diverse group of soft- and hard-bodied fossils, from algae and sponges to chordates and cirripeds (Hagadorn, 2002). Soft-bodied fossils are incredibly rare due to their delicate structure and susceptibility to decay, so it is hard-bodied fossils that more regularly occur in fossil findings. However over 75,000 soft-bodied specimens have been found in the Burgess Shale formation (Hagadorn, 2002). These specimens are preserved in layers of shale formed from deposits of fine mud. One of the most significant species discovered is the Pikaia gracilens. Believed to be an early chordate, the Pikaia gracilens existed very close to the beginning of the evolutionary path that ultimately lead to humans (McGraw-Hill Encyclopedia, 2006).
Zacherl, Danielle. “Biology 171 Evolution and Biodiversity.” National Association of Research in Science Teaching 2007 Annual Meeting, New Orleans LA. (2007):n. page. Print.
When these alterations are helpful, they grow to be fixed in a population and can result in the evolution of new phyla. Evo-devo seeks to figure out how new groups happen by understanding how the method of development has evolved in different lineages. In other word, evo-devo explains the interaction between phenotype and genotype (Hall, 2007). Explanation of morphological novelty of evolutionary origins is one of the middle challenges in current evolutionary biology, and is intertwined with energetic discussion regarding how to connect developmental biology to standard perspectives from the theory of evolution (Laubichler, 2010). A large amount of theoretical and experiential effort is being devoted to novelties that have challenged biologists for more than one hundred years, for instance, the basis of fins in fish, the fin-to-limb change and the evolution of feathers.
“Actions speak louder than words” and I say symbols speak louder than ordinary language. Symbols are everywhere in our life, actually we live in a world full of symbols. They’ve spread widely over the course of the past era. In my opinion, we can not determine when was the first symbol discovered and by whom? Because symbols have many forms and categories. In another meaning, many different forms of symbols were discovered across history. For example: chemistry symbols are totally different than road signs or religious ones. Symbols are in an ever evolving process. If we look around us we notice how we use symbols in our daily life! Millions of people use social media everyday and upload different emojis, which are one form of symbols, which
The world we live in today is full of an exceptional variety of animals. The time it took to conclude to the various sorts of species seen today has been throughout a period of millions of years. The vast majority of these animals are accredited to evolutionary advancements. When the environment changes, organisms have become accustomed to changing to fit their environment, to ensure their species does not die off. These physical changes have resulted in different phyla, ranging from basic structures, like sponges to advance systems, like that of an octopus.
This has significance when looking at pollution and the effects it has on marine life because: “Pollution controls and habitat restoration have had important roles in the recovery of diadromous fishes. Overall, in terms of relative importance of the different factors, it has been shown that 95% of recoveries of exploited marine species in estuarine and coastal regions were enabled by