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What Is Geographic Distribution In Biology

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Skin Malignant Neoplastic Disease

Geographic Distribution

This image shows that the estimated that the life-time hazard of developing skin malignant neoplastic disease is 1 in 100 for work forces and adult females in the UK and the around the universe. This shows that many adult females and money dice for skin malignant neoplastic disease over the old ages.

Therefore skin malignant neoplastic disease can happen anyplace on the organic structure and is more unsafe. It s related to the common mole and alterations in the visual aspect of moles on people s organic structure should be checked by their GP.

Figure 1.1 depicts the per centum distribution of malignant melanoma on parts of the organic structure .Figure 1.1: Percentage distribution of malignant melanoma on parts of the organic structure

Skin malignant neoplastic disease is more common in adult females than work forces with an Meter: F ratio of 4:5. In 2007 it was the 6th most common malignant neoplastic disease in females and the 9th in males: for both sexes combined it was the 6th most common malignant neoplastic disease. The distribution of instances on the organic structure besides varies by sex over a 3rd of male instances arise on the bole of the organic structure, peculiarly the dorsum, while the most common site for females is on the legs.

Earhead Bugs: Calocoris Angustatus

Geographical distribution: South India.

Host range: Pearl Millet, maize, tenai, sugarcane, and grasses.

Bionomics: Adult male is green in color and female is green with a brown margin. Blue cigar-shaped eggs are laid under the glumes or into the middle of the florets. Each insect lays between 150200 eggs in about 7 days. Nymphs are slender, green in color. First instar larva is orange in color. The nymphal period is 1014 days. The life cycle from egg to adult occupies less than 3 weeks. At least two generations of the bug can feed on the same crop when the panicles do not ripen at the same time.

Damage symptoms: The adults and nymphs damage the earheads by feeding on them. They suck the juice from the grains when they are in the milky stage. The sucked-out grains shrink and turn black in color and become ill-filled chaffy. Older grain shows distinct feeding punctures that reduces grain quality.

Species: pictus

Vernacular Names: Insulin plant , keu , kottam , kemuka .

Geographical distribution: C. pictus is a vulnerable, slow growing, and perennial herb of tropical and subtropical regions . It is cultivated at large scale in different parts of India. According to geographical variation, the phytochemical content of the plant and hypoglycemic effects are attributed by rhizome, stem, and leaves .

Karaj S. Dhillon, … Bijay-Singh, in, 2019

Handling And Spatial Analysis Of Plant Species Records In Arcgis

Manual geo-referencing of historical plant species data posed a methodological challenge due to textual descriptions of specimen localities. Specifically, The Flora of Cornwall contains descriptions of species and textual descriptions of geographic localities . In order to manually geo-reference these data and import into GIS software for subsequent spatial and temporal analysis, the following three steps were undertaken:

1) As it would be impractical to geo-reference all plant specimens in West Cornwall as recorded in the Flora of Cornwall , we created a baseline dataset using the New Atlas of the British and Irish Flora . For this baseline dataset, 380 plant species were selected following two rules: a) they were detected in Cornwall pre-1970 by Preston et al. and b) their geographical distribution increased or decreased by more than 50% in the period from 1970 to 2002, also by Preston et al . An electronic database was constructed from these data.

Species without published Ellenberg values , synonyms, or species with incorrect taxonomy were also excluded from the database and subsequent analysis, following suggestions of Lavoie . Taxonomic inaccuracy and possible synonyms were checked in The Plant List, the most extensive online database of all known plant species . In total, 1187 plant specimens from West Cornwall were included in the final spatial analysis database.

Geo-referencing of pre-1900 plant species data.

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Patterns Of Species Distribution

Ecologists who study biogeography examine patterns of species distribution. No species exists everywhere for example, the Venus flytrap is endemic to a small area in North and South Carolina. An endemic species is one which is naturally found only in a specific geographic area that is usually restricted in size. Other species are generalists: species which live in a wide variety of geographic areas the raccoon, for example, is native to most of North and Central America.

Since species distribution patterns are based on biotic and abiotic factors and their influences during the very long periods of time required for species evolution, early studies of biogeography were closely linked to the emergence of evolutionary thinking in the eighteenth century. Some of the most distinctive assemblages of plants and animals occur in regions that have been physically separated for millions of years by geographic barriers. Biologists estimate that Australia, for example, has between 600,000 and 700,000 species of plants and animals. Approximately 3/4 of living plant and mammal species are endemic species found solely in Australia.

Habitat Individual And Population Characteristics

Global distribution of the sickle cell gene and geographical ...

Based on spatial gradients in habitat suitability, species often exhibit an abundant center distribution , wherein the highest population densities are observed in the range core, but the species becomes increasingly rare towards its range margin . The abundant center distribution can be exhibited as reduced numbers of populations at range edges, reduced densities within these peripheral populations, and even reduced fitness of individuals within peripheral populations. Those individuals occurring at range limits experience greater physiological stress due to suboptimal conditions, which influences such factors as dispersal, habitat selection, and subsequent reproductive fitness, or the number of offspring an individual produces that survive to reproduce.

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Vicariance Vs Dispersal: The Case Of The Ratite Birds

Biogeography is a very old discipline, dating back to the time when the first naturalist explorers, such as Alexander von Humboldt , were intrigued by the fact that regions with similar climates like the Mediterranean Basin and Chile in South America exhibited faunas with similar physiognomies but in which the inhabiting species were very different. Conversely, regions such as Africa and South America separated by large geographic barriers like the Atlantic Ocean show faunas of similar composition . One of the best examples of this type of disjunct geographic distribution is that of ratites, a primitive group of birds that includes the ostriches, cassowaries, emus, rheas and kiwis. This clade is distributed in all major southern continents , but how did these flightless birds come to be confined to a distribution scattered across different continents, now separated by thousands of miles of ocean?

Fig. 1

Dispersalism And Centers Of Origin

Two criticisms have been raised against the dispersalist approach to biogeography, especially by cladistic biogeographers : Lack of scientific basis: Since any distribution pattern can be explained by invoking a sufficient number of dispersal events, dispersal-based hypotheses cannot be refuted scientifically within a rigorous hypothetic-deductive framework. Also, if we accept dispersal as a possible explanation for disjunct patterns, vicariance explanations would never be inferred . Lack of predictive power: Dispersal-based hypotheses are lineage-specific, idiosyncratic scenarios that can only explain the biogeographic history of individual lineages but cannot provide a general theory to explain how organisms with different ecologies and dispersal abilities came to occupy the same biogeographic regions and to exhibit similar distribution patterns . As we will see below, this is not necessarily true, and dispersal can sometimes generate congruent distribution patterns similar to those expected from vicariance.

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Historical Plant Species Data

Cornwall has a long history of botanical records that date back to Victorian times, which was encouraged by Natural History Societies at the time, in order to construct regional scientific knowledge . In this study, historical records were used from The Flora of Cornwall , a collection of all known herbarium data in the county of Cornwall and the Scilly Isles from the 18th and 19th centuries. In these records Cornwall is divided into eight botanical districts based on river basins . Geo-referencing was undertaken for the 5th, 6th, 7th and 8th districts that cover the area of West Cornwall . Records contained both native and non-native species. Such historical data contain textual descriptions of localities where plant specimens were found , , rather than explicit definitions of longitude and latitude. We therefore acknowledge several uncertainties in the geo-referencing process: taxonomical inaccuracy spatial error bias associated with frequency and time spent on data collection . The latter uncertainty provides particular challenges and details of our methods for dealing with these uncertainties are given below.

Botanical districts of historical herbarium data in Cornwall.

Showing study area and botanical districts that were used in this research. Figure adapted from Davey .

Statistical Determination Of Distribution Patterns

Evidence for Evolution – Biogeography

There are various ways to determine the distribution pattern of species. The ClarkEvans nearest neighbor method can be used to determine if a distribution is clumped, uniform, or random.To utilize the ClarkEvans nearest neighbor method, researchers examine a population of a single species. The distance of an individual to its nearest neighbor is recorded for each individual in the sample. For two individuals that are each other’s nearest neighbor, the distance is recorded twice, once for each individual. To receive accurate results, it is suggested that the number of distance measurements is at least 50. The average distance between nearest neighbors is compared to the expected distance in the case of random distribution to give the ratio:

R density })\times 2}}}

If this ratio R is equal to 1, then the population is randomly dispersed. If R is significantly greater than 1, the population is evenly dispersed. Lastly, if R is significantly less than 1, the population is clumped. Statistical tests can then be used to determine whether R is significantly different from 1.

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Geographical Distribution Of Malaria Biology Essay

Malaria Lifestyle changes this indicated that malaria affects a batch of people each twelvemonth and is really unsafe disease which kills about a million people. Besides malaria is a harmful disease that has great many people s life style and besides affect around the universe. Peoples can populate their whole life with Malaria if they take the proper medicines or treated good.

The environmental factors that influence the malaria life rhythm and by that the distribution and incidence of the disease are three chief clime Factors these are temperature, precipitation and comparative humidness. This indicated that the minimal temperature needed for the mosquito to develop and the minimal temperature for parasite development which could be between 14+ & A deg C the optimal temperature for mosquitoes to populate and engender in is 20+ & A deg C, and the highest temperature that both parasites and the mosquitoes can last is 40 & A deg C.

Skin malignant neoplastic disease is the chiefly common malignant neoplastic disease in adult females work forces in their mid-twentiess. This indicted Sun exposure is the most of import life style alterations identified to forestall skin malignant neoplastic disease. This besides indicated that the upholding healthy life styles after people have been diagnosed with skin malignant neoplastic disease it can be indispensable to the success of their diagnosing.

Contemporary Plant Species Data

Contemporary spatial records of plant distribution in West Cornwall were obtained from the online Vascular Plants Database of the National Biodiversity Network . The NBN database contains the distributions of 6669 taxa of flowering plants and ferns and contains mostly records from the New Atlas of the British and Irish Flora and records collected by volunteer members of the Botanical Society of the British Isles . NBN Vascular Plant records were validated by BSBI members and obtained at a 10×10 km grid resolution for this study.

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What Is Geographic Distribution

Geographic distribution refers to the way that something is distributed over a geographical area and can be represented on a map. Geographical distribution is commonly used to demonstrate the spread of animal species and plants around the world. However, it can also be used to show the distribution of virtually anything on a map, including disease, pollution and unemployment.

Some distributions can be seen visually without a map. For example, one can see the distribution of houses and green spaces in a city from a tall building or an airplane. Similarly, the distribution of forests, deserts, and water can be seen directly from space or satellite imagery. For most things, geographical distribution is represented on maps overlaid with data.

Geographic distribution can be indicative of interrelated phenomena. For instance, malaria occurs mainly in tropical areas of the world. This is related to the climate in these areas, where the hot and humid conditions are favorable for the mosquitoes that carry the disease to reproduce and thrive. As a result, the geographical distribution of human infections of the disease is most concentrated in tropical areas of the world, and is sparse or nonexistent in non-tropical areas.

Information From Molecular Genetics

Figure 1 from Leopard (Panthera pardus) status, distribution, and the ...

As should be clear from the preceding section, while paleontological data are the only direct information source about past distributions of species, they will forever be limited by the incomplete nature imposed by the vagaries of preservation. As a consequence, the paleontological record will always be incomplete , and other sources of information must be sought. These sources, while certainly less direct and clear, have the opportunity to provide some insight into past distributional patterns for a broader diversity of species. One important source comes from phylogeographic studies of spatial patterns of molecular genetic differentiation among extant lineages across their geographic distributions .

A first question that is addressed in phylogeographic studies is the basic existence of population genetic structure across the distribution of a species, which likely reflects past spatial isolation of populations. Some species indeed do not show such structure , likely as a result of recent origin in a single population. Testing this basic hypothesis offers a first insight regarding past distributions of a given lineagefinding significant population structure leads to a next set of hypothesis tests regarding the nature of that structure .

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Vicariance And Cladistic Biogeography

In the second half of the twentieth century, two scientific revolutions contributed to the appearance of a new paradigm in historical biogeography. The first revolution was the surge of cladistics , a new method to reconstruct evolutionary relationships among organisms based on shared, derived biological characteristics . When competing hypotheses of evolutionary relationships exist, those that imply the minimum number of changes or ad hoc assumptions are preferredthe principle of parsimony or Occam’s razor . The second revolution was the development in the 1960s of the theory of plate tectonics. The Earth’s outer layer, the lithosphere, is divided into rigid rocky plates comprised of continental and oceanic crust that move over the surface of the Earth by sliding on the plastic upper layer mantle, the athenosphere. The idea that species could passively ride on the continents as they split and dispersed across the surface of the Earth led to the concept of vicariance, summarized on the Italian botanist Leon Croizat’s famous sentence: Life and Earth evolve together, meaning that geological barriers evolve together with biotas .

Fig. 2

How Do You Describe Geographic Distribution

Distribution refers to the way something is spread out or arranged over a geographic area. Distribution refers to the way something is spread out or arranged over an area. Recognizing distributions on a map is a starting point for many geographic studies.

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Module 2: Ecology Of Living Things

  • Define the term biogeography and the abiotic factors that impact it
  • Discuss how abiotic factors affect species distribution

Biogeography is the study of the geographic distribution of living things and the abiotic factors that affect their distribution. Abiotic factors such as temperature and rainfall vary based mainly on latitude and elevation. As these abiotic factors change, the composition of plant and animal communities also changes. For example, if you were to begin a journey at the equator and walk north, you would notice gradual changes in plant communities. At the beginning of your journey, you would see tropical wet forests with broad-leaved evergreen trees, which are characteristic of plant communities found near the equator. As you continued to travel north, you would see these broad-leaved evergreen plants eventually give rise to seasonally dry forests with scattered trees. You would also begin to notice changes in temperature and moisture. At about 30 degrees north, these forests would give way to deserts, which are characterized by low precipitation and high insolation .

Species Distribution

Figure 1. Australia is home to many endemic species. The wallaby , a medium-sized member of the kangaroo family, is a pouched mammal, or marsupial. The echidna is an egg-laying mammal.

Check out this video to observe a platypus swimming in its natural habitat in New South Wales, Australia. Note that this video has no narration.

Temporal And Geographic Distribution

Lecture-3: Biogeography

The geographic distribution of Q fever is worldwide. As the clinical presentation is nonspecific, the identification of cases depends upon clinical recognition and the availability of a reference laboratory. Thus, incidence figures for the disease vary widely. In southern France, the incidence of acute Q fever is approximately 50 cases per 100,000 people per year approximately 1 case per 1,000,000 people per year are diagnosed with Q fever endocarditis. Cases of acute Q fever in Europe occur more frequently in spring and early summer . Large outbreaks of Q fever have been reported in several countries in Europe and North America cases and outbreaks are probably underestimated in resource-limited countries.

Betsy Ferguson, David Glenn Smith, in, 2015

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