انتخاب طبیعی (Biodiversity)

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Biodiversity Week Five 

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Biodiversity Biological diversity: is a variety of the Earth’s species, the genes they contain, the ecosystems in which they live, and the ecosystem processes such as energy flow and nutrient cycling that sustain all life. Itis a vital renewable resource. Genes diversity: is a part of BD that enable life on the Earth to adapt to and survive dramatic environmental changes and sustain the life of Earth. Species diversity: is the most obvious component of BD. There are 4-100 million species, 1.8 M identified including a million of insects, 270000 plants, 45000 vertebrate. Ecosystem diversity : is a storehouse of genetic and species D. Functional diversity: is the variety of process such as matter cycling and energy flow taking place within the ecosystems as species interact in food chains and webs 

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(Be eS es ‏حر 010 سس‎ Sustainable © Life depend on energy from sun (solar capital) and on natural resources and natural services (natural capital) provided be the Earth and its biodiversity. ® Living sustainably means living off the earth’s natural income without depleting or degrading the natural capital that supplies it. 

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Natural Capital of Biodiversity and its ecological services © Supplying food, wood, fibers, energy and medicines © Preserving the quality of the air and water ® Maintaining the fertility of soil ® Disposing of wastes and controlling population of pests 

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Biodiversity and Species theories ©» Evolution theory explain how life on the earth changes over time though changes in the genes of populations (Wallace and Darwin) © Populations evolve when genes mutate and give some individuals genetic traits that enhance their abilities to survive and to produce offspring with these characters (natural selection) 

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Process of Biological evolution by natural selection ® Genes mutation ® Individual selection ® Population evolution ® Better adaptation ® Surviving and reproducing under existing environmental conditions 

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مبانی و مفهوم انتخاب طبیعی گونه ها در مجادله دائمی با یکدیگر برای بدست آوردن غذا و سایر منابع برای ادامه بقا هستند. در داخل یک جمعیت گونه ای که دارای توانایی های نسبی است شانس بیشتری برای بقا و تولید نسل دارد این توانایبهای نسبی و مزیتها با ویژگیهای فردی ارگانیسم در داخل جمعیت گونه خود مرتبت است. * این ویژگیهای بقا به ارگانیسم کمک میکند تا در طول فرآیند انتخاب طبیعی بر جمعیت فایق آید. فرایند انتخاب طبیعی هنگامی کامل مبگردد که این ویژگیها با تحول ائیتیکنن قر آرگائیسم همراة گزدفا: تحول ژنتیکی از یک نسل به نسل بعدی را تکامل بیولوژیک ‎acltye Biological Evolution‏ 

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Species Reaction to Environmental Conditions Change ® Adapt to the new conditions through natural selection ® Migrate to an area with more favorable conditions ® Become extinct 

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سه مفهوم غلط مصطلح در تئوری انتخاب طبیعی #مفهوم 5ع111] 0۴ 5۱1۲۷۱۷۵۱ بمعنی بقای نزاد قویتر یا 0۴ 5۳۷۱۷۵1 51۳0۳96۶ 1۱6 نیست بلکه بقای اصلح است. ۴1111655 بمعنى توانايى تطابق با تفییرات و شرائط محیطی بصورت مناسبتر برای تولید نسل بیشتر ‎NV‏ ارگانیسم ویژگیهای خاص ۲۳۵5 را كسب كرده و توسعه میدهد زیرا بدانها زرافه است. نیازمند است یا میخواهد به اين ویژگیها دست یابد. مثال گرد درحالیکه ارگانیسمی باقی میماند که شرایطش بهتر با محیط تطبیق کند. این ارگانیسم ژن ویژگی خاص را در اجدادش داشته که به او برتری را نسبت به سایر ارگانیسم داخل جمعیت داده تا تولید نسل بیشتری را صورت دهد. #تکامل از طریق انتخاب طبیعی براساس یک نقشه کلان و طراحی شده و هدفدار طبیعت صورت گرفته و میگیرد تا گونه هایی با توانایی تطبیق بیشتربا تغفییرات محیطی به گونه های کاملتری مبدل گردند. از منظر علمی در روند تکامل هیچ هدف یا نقشه کلان علمی کمال ژنتیکی مشاهده نميشود. بلکه تکامل یک فرایند اتفاقی. رندومی وانشعابی 0۲3۲/۱109 میباشد 

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)> ( تاثیر روندهای طبیعی بر تکامل گونه ها # پروسه های جغرافیایی بر انتخاب طبیعی از طرق زیر تاتیر میگذارد: گاز طریق جدایی صفحات قاره ای یا 0۱165 86801712 از 225 ميليون سال قبل كه 5 قاره بهم پیوسته بود ۴۵۲9368 تا 135 و 65 میلیون سال قبل که 4 قاره و سپس اکنون که هر 5 قاره جدا و شبه قاره هند از پاتاگونیا جدا و به ارواسیا پیوست. این شرایط دو تاثیر بر حیات در زمين داشت: 1) موقعیت و نحوه قرار گیری اقیانوسها و قاره ها بر اقلیم تاثیر گذارد و برخی از گونه ها را نابود و گونه های دیگری ظاهر شدند. 2) گونه با پیوستن به قاره جدید امکان تحول از طریق انتخاب طبیعی را یافته و با جدا شدن از قاره قدیم امکان تطابق یا حذف را پیدا کردند. برخی گونه ها نابود و برخی ظهور یافتند. زمین لرزه با ایجاد شکاف در پوسته زمین زیستگاهها را از هم جدا و ز تحول در گونه ها را بوجود آورد آتشفشان ها با گسترش غبارها بعضی از زیستگاهها را نابود و بر گونه ها تاثیر گذاردند. 

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‎lees als ١‏ طیسن مر كامل كونه ها ‏* تغییر شرایط حیات در زمین بدلیل پروسه تذ ‏ات اب و هوایی: ‏گرم و سرد شدن مکرر کره زمین در طول حیات خود منجر به ازبین رفتن برخی از گونه ها و ظهور گونه های مقاوم به شرایط جدید محیطی, تغییر زيستكاههاء مهاجرت گونه ها به زیستگاههای جدید و تکامل گونه در ائز ‏یرات زیستگاهی منجر گردیده است ‏وضعیت زمین بدلیل برخورد اجرام آسمانی: ‏در طول زندگی چهار و نیم میلیارد ساله زمین تعدادقابل ملاحظه ای از اجرام آسمانی به کره زمین برخورد و شرایط اکوسیستمی آنرا تغییر و زیستگاهها را جابجا کرده و بر حیات برخی از گونه ها تاثیر گذارده اند. ‎ ‎ ‎ ‎ ‎ ‎ 

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Affecting Biodiversity by: ® Speciation: under certain conditions, natural selection can lead to an entirely new species and two species may arise from one. It takes place in two phases; ® Geographic isolation by: migration for food, earthquake, physical barriers © Reproductive isolation © Extinction happens when an entire species cease to exist. ©» Endemic species are found in only one area and are especially vulnerable to extinction. ©» Background extinction: disappearance of species in low rate (1-5 for every one million species). ® Mass extinction: is a significant rise in extinction rate (20- 70% of species within geological period of 5 million. years) by catastrophic and widespread events. Based on fossil evidence, Earth experienced 5 mass extinction during the last 500 million years (every 20-60million years). A big loss of 95% in 250 million years ago. © Human Activities Conclusion: As environmental conditions changes, the balance between formation of new species and extinction of existing species determined the earth’s biodiversity. 

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(species Diversity and ‏5ا]]‎ ۰ importance © Species Diversity: is an important characteristic of a community and the ecosystem to which belongs. The number of different species which an ecosystem contains (species richness) combined with the relative abundance of individuals within each of those species (species evenness). تنوع گونه ای عبارت است از تعداد مختلف گونه های موجو در یک اکوسیستم (غنای گونه ای) همراه با فراوانی نسبی و تراکم هرگونه در بین گونه های دیگر (یکنواختی گونه ای) ® Species richness normally is contrary to species evenness. © SD of communities varies with their geographical location and decline from equator toward the poles. © The most species - rich ecosystems are tropical rain forests, coral reefs, the ocean bottom zone, and large tropical lakes. 

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۲ . ۴ ‏نظریه تعادل09۲۵0۳ع009 20اوز‎ ۱ © This mode introduce by Robert MacArthur and Edward o. Wilson in 1960s and describe that; the number of different species found in an island is determined by interactions of two factors: © The rate at which new species immigrate to the island and; ° The rate at which species become extinct, or cease to exist, on the island. In balance point or equilibrium point, the rate of species immigration and extinction should balance so that neither rate increasing or decreasing sharply. ©» Two features are effecting the migration and extinction of species in this model: © The size of island (the biggest has the more SD) © The distance with mainland (the nearest is the richest) This model is applicable to National Parks and protected areas surrounded by development 

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fF EON? ARC EET EI ‏زد‎ ‎ecosystems © آیا انبوه گباهی موجب ارتقای غنای گونه ای در یک اکوسیتم میشود؟ و آیا غدای گونه ای موجب یایداری بیشتر اکوسیستم میگردد؟ ® The more diverse an ecosystem is, the more productive it will be, because it produces more plant biomass which support a greater variety of consumer species. © The greater species richness and productivity as well as accompanying web of feeding and biotic interaction in an ecosystem makes it more stable or sustainable to stand with environmental disturbances such as drought and insect infestations. ® David Tilman hypothesize: Communities with higher plant species richness produce a certain amount of biomass more consistently than communities with fewer species. Higher level of biomass less affect by drought, more consume CO2 and N2. © An average annual net primary productivity of an ecosystem reaches a peak with 10-40 producer species. More than that does not necessarily produce more biomass 

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و اد اش 0 مات .از ‎ecosystem‏ ® Ecological niche: each species has a distinct role to play in the ecosystems where it is found. It is a species way of life in a community and includes everything that affects its survival and production (such as water, kind of feed, space, sunlight, temperature etc it needs). It is its pattern of living and is different from its habitat. ® Niche is used for classifying the species into: ® Generalist species: species with a broad niche and ability to live in many different places, eat various foods, tolerate range of environmental conditions. (flies, cockroaches, mice, rats, raccoons, and human) © Specialist species: species that occupy narrow niches and able to live in only one type of habitat, eat a few types of food, and tolerate a narrow range of climatic and environmental conditions 

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ال ال ۳ زر ‎Niche‏ ‎Niche classified in terms of species roles within‏ ® ‎ecosystems to five role.‏ ©» Certain species may play one or more of these roles: ® Native Species: are those that normally live and thrive in a particular ecosystem. © Nonnative Species: are those that migrate or deliberately or accidentally introduce into an ecosystem. They also called invasive, alien, or exotic species. © Indicator Species: provide early warnings of damage to community or an ecosystem such as trout for water quality, birds for environmental changes, butterflies for plant and habitat loss, amphibians for environmental condition and pollution and increase in UV and climate change and global warming, © Keystone Species: are the species that have a large effect on the types and abundances of other species in an ecosystem. (pollination or top predator) ۰ Foundation Species: play a major role in shaping communities by creating and enhancing their habitats in ways that benefit others. (elephants for forest openings, Beavers making wetlands, birds draping seeds) 

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How do species interact ° Five basic types of interaction between species for sharing limited resources such as food, light, shelter, and space: © Interspecific competition: occurs when members of two or more species interact to gain access to the same limited resources © Predation: occurs when a member of one species (predator) feeds directly on all or part of member of another species(prey) ® Parasitism: occurs when one organism (parasite) feeds on the body of, or the energy used by, another organism (host), usually living on or in the host © Mutualism: is an interaction that benefits both species by providing each one limited resources © Commensalism: is an interaction that benefits one species but has little, if any, effect on the other Conclusion: these interaction have significant effects on the resources use and population sizes of the species in an ecosystem.