EKOLOGI EVOLUSI

Evolutionism

Dunia ada dalam waktu yang panjang dan selalu mengalami perubahan, dunia selalu berkembang.

Creationism (Faham Penciptaan) VS Evolutionism (Faham Perubahan)

Creationist

“Tuhan menciptakan sesuatu dengan begitu bijaksana sehingga setiap organisme secara sempurna beradaptasi terhadap lingkungannya di alam”.

Evolusi dan Landasan Pemikiran

• All species are so specialized that they are always absent from almost everywhere

• A great part of the science of the ecology tries to explain:

•Why there are so many types of organisms

•Why their distribution are so restricted

• Darwin & Wallace had read “An Essay on the Principle of Population” published by Malthus in 1798

LANDASAN PEMIKIRAN & HISTORICAL PERSPECTIVE

An answer depend fundamentally on an understanding of the processes of evolution

Malthus (1798): „Population, when unchecked, increases in geometrical ratio. Subsistence increases only in an arithmetical ratio. A Slight acquaintance with number will show the immensity of the first power in comparison of the second. By that law of our nature which makes food necessary to te life of man, the effect of these two unequal power must be kept equal. This implies a strong and constantly operating check on population from the difficulty of subsistence. This difficulty must fall somewhere and must necessarily be severely left by a large portion of mankind“

When unchecked, human population would be capable of doubling every 25 years & overrunning the planet

• Darwin sailed around the world in the 5-year expedition of HMS Beagle (1831-1836) recording & collecting in the enormous variety of environment that he explored on the way

• Wallace explored (with H.W. Bates) 1847-1852 and collected in the river basins of the Amazon and Rio Negro and from 1854-1862 made an extensive expedition in the Malay Archipelago

• Darwin & Wallace were always obsessed by this great truth:

The living world of nature is dominated by reproduction, overcrowding, and death

DEFINISI EVOLUSI DAN LANDASAN TEORIEvolusi

•Proses bertahap dari dunia kehidupan yang berkembang dari bentuk awal suatu kehidupan

•Evolusi = perubahan yang terarah

•Lima teori utama evolusi dari Darwin•The nonconstancy of species

•The descent of all organism from common ancestors (branching evolution)

•The gradualness of evolution (no saltations, no discontinuities)

•The multiplication of species (the origin of diversity)

•Natural selection

•On The Origin of species by Natural selection merupakan teori evolusi yang banyak mengilhami perkembangan biologi

NATURAL SELECTION (Seleksi Alamiah)• Individu dari spesies yang membentuk populasi tidak identik

(Individual that form a population of a species are not identical)

• Variasi antar individu merupakan sifat yang diturunkan(Some of the variation between individuals is heritable)

• Sebagian besar populasi memiliki kemampuan untuk melakukan pertumbuhan eksponensial untuk melebihi kemampuan lingkungan, akan tetapi sebagian besar individu akan mati sebelum reproduksi dan umumnya akan memiliki kemampuan reproduksi yang di bawah kemampuan potensialnya

(All population are capable of exponential growth that would greatly overwhelm the environment, but most individual die before reproduction and most (usually all) reproduce at less than their maximal rate)

• Tetua yang berbeda akan melahirkan keturunan yang mana keturunannya tidak memiliki kontribusi yang sama terhadap generasi berikutnya

(Different ancestors leave different of descendants (N.B. descendants, not just offspring): they do not all contribute equally to subsequent generation

Given the four truths, the heritable feature that define a population will change over time. Evolution will happen

THE SURVIVAL OF THE FITTEST Fitness is the proportionate contribution that an individual makes to future

generation (The contribution made to a population of descendants by an individuals relative to the contribution made by others in its population. The relative contribution that an individual makes to the gene pool of the next generation)

The fittest individuals in a population are those that leave the greatest number of descendants relative to the number of descendants left by other individual in the population having greatest influence on the heritable characteristic of population

Selection conducted by human (breeder) has the same direction. The different is in particular that human selection has an aim for the future. Evolution happens because some individuals have survived the death and destruction of the past, not because they were somehow chosen or selected by “Mother Nature” as improvement for the future case study INDUSTRIAL MELANISM on Biston betularia, first black specimen 1848, by 1895 98%

Evolution forces the characteristics of population to diverge from each other only if there is sufficient heritable variation on which selection can act and provided that the forces of selection favoring divergence are strong enough to counteract the hybridization which promote mixing. Two population will not diverge completely if their members are continually migrating between them, mating & mixing their genes

MODEL OF NATURAL SELECTIONNatural selection change the character of a population by shifting out and eliminating much of its variation and leaving behind a residue for future generation with a narrower range and more restricted potential. This is commonly pictures as a force that drives population toward peaks of perfection– of perfect match between organism and environment (optimistic view). An alternative picture of natural selection is that it forces population into ever-narrowing ruts of overspecialization—ever-deepening traps.

Figure (a) An optimistic & (b) A pessimistic interpretation of natural selection. Horizontal plane represent dimension of a range of environment condition. In (a) The vertical scale is a measure of the range of fitness of the organism in the population and natural selection is shown as arrows driving the population to ever higher “adaptive” peaks. Population 1 is highly variable and tolerates a wide range of conditions. Natural selection is relatively weak. Population 2 is a very uniform population, and natural selection is fierce and driving the population to very high degree of specialization and local fitness. In (b) Natural selection is shown as arrows driving the population into ruts, troughs, and pits. The vertical downward axis is a measure of the intensity of specialization. The highly variable population with weak selection is rather safe if the environment change but population 2 is at extreme risk of extinction. The two depictions should not been as one right and one wrong impression of natural selection in action, but rather as two views of the same truths

THE ECOLOGY OF SPECIATION On the origin of Species is about natural selection and evolution but is not really about

the origin of species The origin of species is normally a process rather than an event Concept of Species

– Phenetic species concept ciri-ciri morfologi – Biological Species consept berdasarkan perkawinan– The recognition species concept (species mate recognition/SMRS) cara-cara

umum mengenal pasangan. Mekanisme isolasi merupakan sebab yang mengawali munculnya spesies baru

– Ecological species concept persamaan peranan dalam ekosistem

ISOLATION & EVOLUTION as main factors to form a new true BIOSPECIESIsolation (barrier) prevents gene flow between two population

Isolated population may then evolve and become so different that, if two population meet again, they can no longer hybridize and their population can no longer exchange genesFigure based on Model of Mayr (1942). A uniform species with a large range (1) differentiates (2) into local forms, varieties, or subspecies, which (3) become genetically isolated from each other, for example, separated by geographic barriers or dispersed onto different island. After evolution they may meet again when they (4) are unable to hybridize and have become true bio-species or (5) retain an ability to hybridize and form hybrid zones—not true biospecies

KONSEP SPESIESSPESIES

Merupakan istilah untuk menyebutkan tingkat terendah dalam penggolongan organisme dalam konteks klasifikasi

• Kingdom : Animalia

• Phylum : Arthropoda

• Class : Insecta

• Ordo : Lepidoptera

• Family : Noctuidae

• Genus : Spodoptera

• Species: litura

EFFECTS OF CLIMATE CHANGE ON THE EVOLUTION & DISTRIBUTION OF SPECIES

Much of what we see in the present distribution of species and animals on Earth represents phases in a recovery from past climatic change.

Changes in climate, particularly during the ice ages of the Pleistocene (the past 2-3 mill. Years), bear a lot of the responsibility for the present patterns of distribution of plants and animals

As climate have changed, species population have advanced and retreated; have been fragmented into isolated patches, terrestrial “island” in a sea of other vegetation; and have then rejoined

The patterns of species formation that occur on islands appear on an even larger scale in the evolution of genera and families across continents.

The occasional rare events of dispersal undoubtedly account for some of the invasions and subsequent isolation across oceans.

Biologists (especially Wegener 1915), met outraged scorn from geologists and geographers when they argued that it must have been the continents that had moved rather than the organism that had dispersed Continental Drift

The established drift of the continents answers many questions in the ecology of evolution, eg. for distribution of large flightless birds

FAKTOR DISTRIBUSIa. Terbawa oleh manusia

b. Migrasi

c. Aerial plankton

d. Continental drift sebagai konsekuensi dari Plate Tectonic

Figure (a) The distribution of terrestrial flightless birds, (b) The phylogenetic tree of the flightless birds and the estimated times (mill years [Meyr]) of their divergence. (After Diamond, 1983; From data of Sibley & Ahlquist.).

Techniques of molecular biology make it possible to analyze the time at which the various flightless birds started their evolutionary divergence. The Tinamous seem to have been first to diverge and became evolutionary separate from the rest, the ratites. Australia became separated from the other Southern continents leaving the ancestral stock of ostriches & rheas to be separated when the Atlantic opened up between Africa & South America. The Tasman Sea opened up about 80 million years ago and ancestors of the kiwi are thought to have made their way, by island hopping, about 40 mill years ago across to New Zealand, where divergence into the present species happened relatively recently

Faktor yang mana yang paling memungkinkan untuk distribusi flightless birds?

PLATE TECTONIC SALAH SATU PENYEBAB ISOLASIa. 200 juta tahun yang

lalu, bumi masih satu

b. 135 jt thn yg lalu, Grondwanaland & Laurasia terbelah

c. 65 jt thn yg lalu, Amerika latin dan Afrika terpisah

d. Keadaan saat ini

e. 50 jt thn ke depan, Australia bergerak ke utara, Samudra India dan Atlantik semakin lebar. Di wlayah California akan semakin banyak pulau

INTERPRETING THE RESULTS OF EVOLUTION: CONVERGENT AND PARALLEL EVOLUTION

Convergent evolution = the process by which organisms of different evolutionary lineages to have similar form or behavior

Parallel evolution = the evolution along similar lines of systematic groups that had been separated geographically at an earlier stage in their history

Figure of an example of convergent evolution of body form among large marine carnivore from different evolutionary lines

Figure of an example of parallel evolution of marsupial & placental mammals. The pairs of species are similar in both appearance & habit & usually (but not always) in life-style

FAKTA-FAKTA EVOLUSI• Kesamaan organ internal dan eksternal pada

vertebrata• Kesamaan pola perkembangan embrio pada

vertebrata• Banyak vertebrata memiliki organ vestigial• Rekaman fosil• Proses biogeografi• Kesamaan DNA

Figure (a) Map of the Galapagos Islands showing their position relative to Central America; on the equator 5o equals approximately 560 km, (b) A reconstruction of the evolutionary history of the Galapagos finches based on variation in the length of micro-satellite deoxyribonucleic acid (DNA). The genetic distance (a measure of the genetic difference) between species is shown by the length of horizontal lines. Notices the great and early separation of the warbler finch (Certhidea olivacea) from the others, suggesting that it may closely resemble the founders that colonized the islands. G = Geospiza, C = Camarhynchus, Ce = Certhidea (Petren at al. 1999. A phylogeny of Darwin’s finches based on microsatellite DNA variation. Proc. The Royal Soc. Lond, Series B, 266: 321-329).

REMARKS There is a temptation to regard each case as an example of evolved

perfection. But there is nothing in the process of evolution by natural selection that

implies perfection No population of organisms can contain all the possible genetic variants

that might exist and might influence fitness. The evolutionary process works on the genetic variation that is available It favors only those forms that are fittest from among the range of variety

available, and this may be a very restricted choice. The very essence of natural selection is that organisms come to match

their environments by being “the fittest available” or “the fittest yet”: they are not “the best imaginable”

KOEVOLUSIKoevolusi

Evolusi yang paralel dari dua organisme yang saling terkait atau salah satu tergantung dari yang lainnya. Perubahan yang terjadi pada satu organisme akan diikuti oleh adaptasi yang lainnya

• Predator vs mangsanya

• Bunga dan Pollinator

• Hama dan tanaman

• Penyakit dan inangnya