Dessi Endriyani

Ecological Succession - Summary An example of succession. Open water such as a lake or pond eventually becomes climax woodland. Hold your mouse pointer over each image for more information or for a full explanation click here . Ecological succession is the gradual process by which ecosystems change and develop over time. Nothing remains the same and habitats are constantly changing. There are two main types of succession, primary and secondary. Primary succession is the series of community changes which occur on an entirely new habitat which has never been colonized before. For example, a newly quarried rock face or sand dunes. Secondary succession is the series of community changes which take place on a previously colonized, but disturbed or damaged habitat. For example, after felling trees in a woodland, land clearance or a fire. The Major Points: ...

An invasive species is a species occurring, as a result of human activities, beyond its accepted normal distribution and which threatens valued environmental, agricultural or other social resources by the damage it causes. Invasive species have a major impact on Australia's environment, threatening our unique biodiversity and reducing overall species abundance and diversity. Invasive species include: diseases, fungi and parasites Invasive diseases, fungi and parasites in Australia affect many native plants and animals and agricultural crops. Quite often when plants and animals have come into contact with introduced diseases, fungi or parasites they do not respond well to treatment. Vaccines are often very expensive to produce and are not feasible to apply broadly to wild animals. Some diseases have contributed to significant losses of species leading to some species becoming threatened or extinct. Some of the diseases, fungi and parasites currently of concern ...

By far the most popular way to measure the size of a population is called the Mark and Recapture Technique. This technique is commonly used by fish and wildlife managers to estimate population sizes before fishing or hunting seasons. The mark and recapture method involves marking a number of individuals in a natural population, returning them to that population, and subsequently recapturing some of them as a basis for estimating the size of the population at the time of marking and release. This procedure was first used by C.J.G. Petersen in studies of marine fishes and F.C. Lincoln in studies of waterfowl populations, and is often referred to as the Lincoln Index or the Petersen Index. It is based on the principle that if a proportion of the population was marked in some way, returned to the original population and then, after complete mixing, a second sample was taken, the proportion of marked individuals in the second sample would be the same as was marked initially in the tota...

POPULASI    Populasi adalah sekelompok individu sejenis yang terdapat di suatu daerah   tertentu. Populasi dapat didefinisikan pada berbagai skala ruang. Bahkan seluruh individu sejenis dapat dipandang sebagai sebuah populasi. Beberapa   populasi local atau deme yang dihubungkan oleh individu-individu yang menyebar disebut metapopulasi. Populasi sementara yang terdiri atas tahap tertentu dari daur hidup suatu organisme membentuk hemipopulasi. Beberapa karakteristik populasi di antaranya adalah kepadatan, ukuran, dispersi, rasio kelamin, struktur atau komposisi umur, dan dinamika. Penyebab Perubahan Populasi (1)    Persaingan intraspesifik mempengaruhi kelahiran, kematian, dan pertumbuhan individu-individu melalui cara terkait kepadatan. Pengaruhnya datang perlahan, yaitu pertama-tama melibatkan kualitas hidup daripada kelangsungan hidup individu. Selanjutnya, ketika dampaknya semakin meningkat, persaingan intraspesifik mempengaruhi kebugaran in...

Populasi Populasi didefinisikan sebagai kelompok organisme spesies yang sama yang menduduki ruang atau tempat tertentu, memiliki berbagai sifat tertentu sebagai sifat dari kelompok tersebut dan bukan sifat individu. Beberapa dari sifat tersebut adalah kerapatan, natalitas (laju kelahiran), mortalitas (laju kematian), penyebaran umur, potensi biotic, dispersi, dan bentuk pertumbuhan atau perkembangan.. Populasi juga memiliki sifat-sifat genetic yang secara langsung berkaitan dengan ekologinya, misalnya sifat adaptif, sifat keserasian reproduktif, dan ketahanan. Kepadatan (densitas) populasi: jumlah individu suatu spesies per satuan luas atau volume. Faktor-faktor yang mempengaruhi penyebaran populasi: •Distribusi sumberdaya •Perilaku sosial (pada hewan) •Faktorlain (interaksiorganisme, tempat berlindung,oksigen terlarut, dll). Kurva Pertumbuhan Eksponensial (kurva berbentuk hurufJ) Faktor Pembatas Pertumbuhan Populasi Faktor pembatas : •tergantung ke...