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Pertanyaan via email. Populasi Efektif (N e ) lanjutan. Sejenis anjing laut (1 jantan vs gerombolan betina) N e = (4 Nm x Nf)/(Nm + Nf) Nm = N jantan matang seksual Nf = N betina matang seksual. Paper : mating behavior. Species and Speciation. Aktualita: Nobel Prize 2008 O. Shimomura
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Populasi Efektif (Ne) lanjutan Sejenis anjing laut (1 jantan vs gerombolan betina) Ne = (4 Nm x Nf)/(Nm + Nf) Nm = N jantan matang seksual Nf = N betina matang seksual
Species and Speciation Aktualita: Nobel Prize 2008 O. Shimomura M. Chalfie R. Tsien
BioluminescenceBioluminescence, the emission of light from a living organism, is demonstrated by the comb jellyfish shown here. This emission also occurs in bacteria, dinoflagellates, fungi, and in many kinds of animals including insects, and fish. Specialized structures called photophores are found on the surface of a bioluminescent organism. The photophores contain the molecule luciferin and the enzyme luciferase, which act together in a cycle to emit flashes of light. Bioluminescence serves a variety of functions. It can be used to attract prey, disguise an organism from a predator, signal a mating partner, or act as a flashlight in the murky depths of the ocean.
Jellyfish variation environmental changes selection type of selection speciation species environmental changes variation … so on ………………………
Geographic Variation • Geographic variants reflect the selective environmental forces acting on various genotypes, adapting each population to the locality it inhabits
Cline • Cline: some measurable gradual change over a geographic region in the average of some phenotypic characters e.g size, coloration, gene freq etc
Cline (cont) • Cline are usually associated with an ecological gradient such as temperature, moisture, light or altitude • Because environmental selection pressures vary along the gradient, any one population will differ genetically to some degree from the other • There for: population at the two extremes along the gradient may behave as different species
Clinal Differences: • Animal: size, body proportion, coloration, physiological adaptation Deer, Mosquito, Frog
This beetle is a member of the weevil family, the largest beetle family with over 50,000 species identified. Weevils primarily feed on plants, boring into plant tissue with their long, slender beaks. Scientists estimate that nearly every terrestrial plant species on Earth has at least one weevil species that feeds on it.
Cline (cont) Plant: size, time of flowering, depth of root Exp : Bamboo, Tapak Liman, grass, Durian
Ecotype • a subgroup of a species of plant or other organism whose members show genetically determined adaptations to certain environmental conditions in their habitat and reflect abrupt changes in selection pressure • Abrupt: environment disaster, sub lethal dosage • Unique local environment
Ecotype (cont) • Mountain top vs bottom of the slope with intermediate form • Scatter like a mosaic • Different climate at various altitude • Indonesia: wereng dan moa
Geographic isolates • Geographic isolation subpopulation population etc (river, canyon, sea etc) • Extrinsic barrier • Degree of isolation depends upon the barrier • Indonesia: orang utan
Polymorphism • Polymorphism: several; distinct forms of a species in the same habitat at same time • Forms are distinct, discontinues, no intermediate • (Biston, turtle)
Isolating Mechanism • Morphological distinctive • Behavioral • Habitat selection • Temporal isolation • Ethological barriers (difference of courtship and mating behavior)
Allopatric Speciation • Allopatric (geographic speciation, two spatially isolated populations, mountain uplift, land sinks, other catastrophe) reproductive isolation complete barrier broken, species exist sympatrically A’ B A & B A A’ A”
Parapatric speciation • Invade new habitat • Little genetic interchange • New species adapted to new habitat • Characteristics of short lived, rapidly reproducing species (snail, rat, grass) B A’ A A A
Sympatric speciation • Take place at the same habitat • Polymorphism forms • Genetic race evolve • New species exploits new habitat, niche • Example: parasitic insect A’ A & A’ B A” B A A
Polyploidy • Adaptive Radiation • Convergence • Gradualism • Punctualism
Evolution among some populations is always taking place somewhere on earth
Evolution among some populations is always taking place somewhere on earth Speciation S.p.e.c.i.e.s STOP / GOES ON ?