Discerning the spatial patterns of biodiversity and understanding their ultimate (why) and proximate (how) causes is very dear to biogeography and is one of the key concepts of Macro ecology. Some places on earth contain more species as compared to others. All species occurring at a given space and time either originated (speciated) there or dispersed and arrived from another place and settled there. Biogeographers try to understand the past and current distributions of species by incorporating historical, evolutionary and ecological factors. Earlier biogeographers or the ‘naturalists’ in their sacred quest to serve ‘the creator’, travelled to various parts of the world and imparted valuable knowledge about the diverse patterns and processes of nature. Linnaeus (1743), on the one hand, hypothesized that early Earth was filled with water except for it’s highest mountain top i.e., Mount Ararat which was known to be the site of paradise and as the sea level dropped the exposed land was colonized by plants and animals that migrated down from high elevational zones of Mount Ararat whereas Willdenow (1805) hypothesized that within each geographical region of the earth, plants and animals were first placed and later survived the great flood on many mountain ranges (Lomolino,2001). Von Humboldt and Darwin in the South American Andes and Wallace Southeast Asian islands noticed the decreasing trend in elevational species richness patterns (McCain and Grytnes, 2010). Later work done by Grinnell (1917), Whittaker (1952), Terborgh (1977, 1985) on elevational species richness became accepted and set a established pattern for all species for more than two decades (McCain and Grytnes, 2010). However current researches on elevational gradients are... ... middle of paper ... ...t montane regions have high species diversity due to allopatric and parapatric speciation favored by topographic complexity and climatic zonation (Kozak and Wiens, 2010). Two hypotheses gas been put forward in an attempt to explain 2. Montane museum hypothesis- Montane regions have higher species richness at intermediate level simply because these elevation was occupied for the longest time which means high time for speciation and accumulation of species (Kozak and Wiens, 2010). In their study, (Kozak and Wiens, 2010), have shown that Time-for-speciation plays important role in generating hump shaped pattern in case of North American salamanders. They have shown that the ancestors of all existing plethodontids in eastern North America occurred predominantly at intermediate elevations and species occurring at higher and lower elevations have colonized them recently.
Williams, A. B. (1936). The composition and dynamics of a beech-maple climax community. Ecological monographs, 6(3), 317-408.
Biodiversity is influenced by landscape fragmentation at various scales of space and time. The extinction of ecosystem types and component species may cause an increased patchiness of the landscape, resulting in lower population sizes and decreased connectivity. As a result, inhabitants may experience decreased dispersal abilities and lowered gene flows between populations.
“For whatever reason, there has been a continued pattern of misinterpreting or incorrectly describing multiregional evolution.” (Wolpoff et al. 2000)
...s from the Paleozoic, Mesozoic, and Cenozoic periods show proof of how animals have gone through evolution and why certain fossils look very similar. The Law of Original Horizontality and the Law of Superposition both express true when looking at modern rock layers today. The Law of Original Horizontality happens when sediments are constantly deposited over old layers of rock forming new layers over millions of years, while the Law of Superposition is the law that older rock layers lie beneath the newer layers. Also, Pangea and Panthalassa are now the seven continents and four oceans of the world today as a result of Continental Drift. All things considered, Rock layers are therefore evidence of Evolution for, rock layers holds proof of evolving animals seen through fossils, the plates in the earth separated Pangea, and the relation of evolution and rock layers.
The ecosystem I have chosen is tropical rainforest. In the following paragraphs, I am going to firstly introduced the structure of tropical rainforest in brief, with the second part of the plant ecology and last the diversity within this ecosystem.
... but similar areas. They put some in isolation and some went into a mixture of other species. It was discovered that the species in the mixture evolved more diversely than those that were in isolation. They also discovered that the mixture of species changed the way they used resources. This showed that the species that evolved together were more productive than the species in isolation. The final conclusion was that “species interactions can have a major effect on evolutionary dynamics, which can in turn influence ecosystems functioning” (Timothy G Barraclough).
The concept of transitional species is an important and complex notion in evolutionary biology. To begin with, there is no such thing as transitional species since all living things were always evolving in the past, not stopping at one stage or another, and they will continue to evolve in the future. In terms of evolutionary biology, we use the concept of transitional species as a way to dim ambiguity. Much like the use of the Linnean taxonomic system of species, we come up with concepts like transitional species to organize and classify species in order to understand their evolutionary roots and how those species changed through life’s history to become what they are today. “In the same way that the concept of species can be provisionally meaningful to describe organisms at a single point in time, the concept of transitional species can be provisionally meaningful to describe organisms over a length of time, usually quite a long time, such as hundreds of thousands or millions of years” (111). Though it can be difficult to distinguish what can be considered an ancestral species from another, the fossil record can show us how species change through time as they develop ways to adapt to stresses found in their environments. “In the modern sense, organisms or fossils that show intermediate stages between ancestral and that of the current state are referred to as transitional species” (222). The concept of transitional species is, in essence, fairly straight forward. This paper will outline the concept of transitional (or sometimes termed intermediate) species and the latter’s role in evolutionary biology, as well as go in depth about several common transitional species: Tiktaalik, an animal at the cusp between life in the water and ...
The current level of conceptual understanding of the effects of biodiversity on ecosystem processes is so primitive that at this stage it is possible to recognize the linkages at the level of functional groups only. In any ecosystem there are diverse types of functions performed by different species or species groups. However, no two species or individuals are identical. It may be noted that some species diversity within the functional groups or genetic diversity within the species has important ecosystem
The biodiversity of this particular biome is vast and rapidly growing. One of the main reasons that there are so many species and animals living within this biome is due to the constant warm weather. It also supplies an almost 100% chance of water and food for the animals within. Small animals, including monkeys, birds, snakes, rodents, frogs and lizards are most common in tropical rainforests. Most of these animals and some insects rema...
Mills, Scott L., Daniel F. Doak, and Michael E. Soule. "The Keystone-species Concept in Ecology and Conservation." BioScience 43.4 (1993): 219-25. Apr. 1993. Web. 30 Oct. 2011.
On the first level, when foreign, but previously non-invasive species is first introduced to a new area, the new species may play a role in a community that was previously unfulfilled; it may fill a vacant niche in the ecosystem. Originally this new species may be seen as a useful contributor to its new surroundings because it has only (temporarily) increased biodiversity in the area (Meinesz, 2003).
There are many reasons for differing diversity and abundances of species between two countries, and I believe I have touched on the most important aspects of them all. It looks as though Spain’s proximity to the equator is the driving force behind its high species numbers, but as all organisms are different and prefer various habitats and environments, that there are also a lot of problems with comparing and analysing data. In this time of climate change, all that we know about species diversity could change and so studies such as this are very important in understanding how global temperature change and melting ice caps affect the organisms that live on this planet.
Diversity of species is influenced by the type of forest where the species is located. To determine the value of a forest, one must ask oneself the question “How does a forest affect you?” Forests affect us in ways of aesthetics, monetary gains, product supplement and any other utilization that proves beneficial. This is true of both tropical and temperate forests.
There are lots of environmental issues going on globally. The earth faces problems such as pollution, global warming, waste disposal, and loss of biodiversity. These are just a small amount of issues out of the so many. These environmental problems pose an abundant amount of risk to the health of humans and animals. There needs to be a solution to all these problems and that is by informing others, so that way everyone can make the environment a better place.