Dinamik Populasi Ekologi

Populasi kumpulan individu daripada spesies yang sama yang menduduki kawasan yang sama

Komuniti terdiri daripada dua atau lebih populasi yang menduduki kawasan yang sama Ekosistem terdiri daripada satu atau lebih komuniti dan persekitaran abiotiknya.

Saiz Populasi Bilangan individu yang terdapat pada sesuatu masa Saiz populasi Golden toad = 1,500+ in 1987, and zero a few years later.

1. Taburan PopulasiPerubahan dalam Saiz Populasi Struktur / Taburan Umur Populasi 4 Pertumbuhan Populasi- Potensi Biotik- Rintangan Alam Sekitar, - Keupayaan Muatan5. Kepadatan Populasi - Density dependent and Density Independent Control - Jenis lengkung populasi6. Pola Pembiakan dan Kemandirian - Strategi r dan Strategi K - Survivorship curve

Dinamik Populasi:Trenda perubahan populasi terhadap keadaan persekitaran

Taburan Populasi Susunan spatial individu Figure 5.8RandomClumpedUniform

Taburan Populasi:Bagaimana individu-individu ditaburkan dalam sesuatu kawasanRANDOMUNIFORMCLUMPEDTerdapat 3 pola taburan populasi SERAGAMKELOMPOKRAWAK

Taburan Populasi

Copyright 2002 Pearson Education, Inc., publishing as Benjamin CummingsTaburan Kelompok(Clumped Dispersion)

Taburan populasi kebanyakkan spesies ialah berkelompok. Kenapa?Sumber-sumber yang diperlukan adalah berbeza dari satu tempat ke tempat yang lain.

Perlindungan yang lebih baik daripada pemangsa. (cth: gajah)

Peluang yang lebih baik untuk spesies pemangsa mendapat makanan. (cth: serigala)

4. Kelompok sementara untuk membiak dan menjaga anak

Taburan Seragam (Uniform Dispersion)Lebih peluang untuk mendapat sumber yang kurang

Taburan Rawak (Random Dispersion)

VIDEO

POPULATION DISTRIBUTION

Perubahan dalam saiz populasi

Faktor yang mempengaruhi saiz atau kepadatan populasi Kelahiran Kematian EmigrasiImmigrasiPopulasi (N)

Perubahan dalam saiz populasiSaiz Populasi =(Kelahiran + Immigrasi) (Kematian + Emigrasi)

STRUKTUR UMUR : (Taburan Umur)Pecahan individu pada peringkat umur yang berlainan dalam sesuatu populasi

Struktur Umur Populasi Memberi kesan pada kadar kenaikan atau penurunan saiz populasi

Boleh meramal pertambahan populasi masa depan

Struktur Umur Populasi Jika kurang individu umur reproduktif populasi akan bertambah dengan kadar perlahan

Copyright 2002 Pearson Education, Inc., publishing as Benjamin CummingsFig. 52.22Struktur Umur Populasi

Pertumbuhan Populasi Potensi Biotik (biotic potential) ialah keupayaan pertumbuhan sesuatu populasi

Kadar Pertambahan Intrinsik (intrinsic rate of increase) (r) ialah kadar pertumbuhan populasi jika terdapat sumber yang tidak terhad.

Individu dalam populasi yang mempunyai kadar pertumbuhan intrinsik yang tinggi biasanya membiak pada peringkat umur muda tempoh di antara generasi pendek membiak beberapa kali menghasilkan banyak anak setiap kali membiak

Carrying Capacity (Keupayaan Muatan)

Potensi Biotik Rintangan Keupayaan Alam Sekitar Muatan

Keupayaan Muatan ialah populasi maksimum sesuatu spesies yang boleh dikekalkan oleh habitat tanpa degradasi habitat.

Biotic Potential

Carrying capacity (K)Environmental resistanceBioticpotentialExponentialgrowthPopulation Growth CurvesTime (t)Population size (N)

Potensi Biotik Rintanganalam sekitar

Keupayaan Muatan

Pertumbuhan Eksponen vs Pertumbuhan Logistik Kadar pertumbuhan populasi menjadi perlahan apabila saiz populasi menghampiri keupayaan muatan

Contoh Pertumbuhan EksponenKruger National Park, South Africa

Pertumbuhan Populasi Logistik Kambing Biri-biri OvershootCarrying CapacityYearNumber of sheep (millions)2.01.51.0.5180018251850187519001925

Pertumbuhan Eksponen, Overshoot dan Population Crash ReindeerPopulationOvershootsCarrying CapacityPopulationcrashesCarrying capacityYearNumber of sheep (millions)2,0001,5001,000500019101920193019401950

Pertumbuhan Eksponen dan Logistik

Kepadatan PopulasiKepadatan populasi ialah bilangan individu sesuatu populasi dalam sesuatu kawasan

Jenis Lengkung Perubahan Populasi Semulajadi

Peranan Pemangsa Dalam Mengawal Saiz PopulasiPredator-prey cyclesTop-down controlBottom-up control

VIDEO

POPULATION BIOTIC POTENTIAL

Pola Pembiakan dan Kemandirian Spesies Pembiakan aseksual Pembiakan seksualKelemahanIndividu jantan tidak menghasilkan anakKesilapan genetik boleh berlakuUpacara mencari pasangan membazir tenaga dan masaKekuatan Diversiti genetik kemandirian tinggiIndividu jantan mencari makanan dan memberi perlindungan

Pembaziran tenagaSockeye salmon, berenang 6,000 km dari Lautan Pasifik ke muara sungai, bertelur beribu-ribu telur dan mati kepenatan.

Pola Pembiakan dan Kemandirian Spesies Spesies dengan keupayaan pertumbuhan populasi tinggi Spesies dengan keupayaan pertumbuhan populasi rendah

K-strategistsTerms come from:

K = symbol for carrying capacity. (Populations tend to stabilize near K.)

African elephants produce one offspring at a time, once every few years over a long lifetime, and protect each offspring intensively (much like humans) Few NumberMore resources per individualMore chance of accidental loss

r-Selectedr = intrinsic rate of population increase. (Populations can potentially grow fast, have high r.)

By contrast, many plants and some insects, reproduce once (annually), producing vast numbers of seeds/eggs that are poorly protected, if at all Large NumberLess resources per individualMore chances of successSome fish such as cod (millions of eggs)

Carrying capacityK species;experienceK selectionr species;experiencer selectionKPositions of r-selected and K-selected Species on Population Growth CurveNumber of individualsTimeNumber of individuals

R-selected atau K selected?TURTLE

Life History Strategies: Two general types

Life History traitr-strategists, OpportunisticK-strategists, EquilibriumOffspringMany, small (high r)Fewer, large (low r)Offspring survivalLowHighParental careRareCommonReproductive ageEarlyLaterReprod. seasons1-fewManyHabitatUnstable, temporaryStable, permanentCompetitivenessLowHighPopulation regulationDensity independentDensity dependentPopulation fluctuationIrruptiveStable near K

3 Jenis Survivorship Curves123

Survivorship curve.Menunjukkan mortaliti (kematian)individu pada peringkat umurberlainanType I curve- mortaliti rendah peringkat umur muda (cth kambing, manusia)Type II curve mortaliti sama tinggi pada setiap peringkat umur (constant) (cth burung, tupai)Type III curve mortaliti tinggi peringkat umur muda (cth oysters)

Survivorship Curve

The human population increased relatively slowly until about 1650 when the Plague took an untold number of lives.Ever since, human population numbers have doubled twiceHow might this population increase stop?The human population has been growing almost exponentially for three centuries but cannot do so indefinitely

Copyright 2002 Pearson Education, Inc., publishing as Benjamin CummingsFig. 52.20

POPULATION CYCLESHUMAN POPULATION1650 - 500,000,0001850 - ONE BILLION1930 - TWO BILLION1975 - FOUR BILLION2010 SIX BILLION2017 - EIGHT BILLION

Ramalan saiz populasi tahun 2050.Anggaran Keupayaan Muatan Bumi untuk manusia

Human Growth Rate1.15 - 2005

We may never know Earths carrying capacity for humans, but we have the unique responsibility to decide our fate and the fate of the rest of the biosphere.

1. Taburan PopulasiPerubahan dalam Saiz Populasi Struktur / Taburan Umur Populasi 4 Pertumbuhan Populasi- Potensi Biotik- Rintangan Alam Sekitar, - Keupayaan Muatan5. Kepadatan Populasi - Density dependent and Density Independent Control - Jenis lengkung populasi6. Pola Pembiakan dan Kemandirian - Strategi r dan Strategi K - Survivorship curve

Dinamik Populasi:Trenda perubahan populasi terhadap keadaan persekitaran

*****Reindeer introduced to Bering Sea islandExponential growth, overshoot, population crash, Ireland-Easter Island****Many types of fish migrate on a regular basis, on time scales ranging from daily to annual, and over distances ranging from a few meters to thousands of kilometers. Fish usually migrate because of diet or reproductive needs, although in some cases the reason for migration remains unknown.Some of the best-known anadromous fish are the five species of Pacific salmon, which are Chinook (King), Coho (Silver), Sockeye (Red), Chum (Dog) and Pink (Humpback). The salmon hatch in small freshwater streams. From there they migrate to the sea to mature, living there for two to six years. When mature, the salmon return to the same streams where they were hatched to spawn. Salmon are capable of going hundreds of kilometers upriver, and humans must install fish ladders in dams to enable the salmon to get past. Other examples of anadromous fishes are sea trout, three-spined stickleback, and shad.Different reproductive patterns to help ensure survival******Different reproductive strategies have different life expectancies. 3 types of survivorship curves*