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7/29/2019 Englis Task

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THE ORIGIN OF SPECIES

Muhammad Nur Hasan (11620060)Rudin Wijiono (11620061)Ainiyatul Fikriyah (11620062)

Rizkia Rodhia Rohima (11620063)

Supervised by: Oktavia Widiastuti, M.Pd

Written by:


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The 7th Group @Bio-B

INTRODUCTION

In Origin of Species, Charles Darwin introduced the

concept of natural selection. Natural selection is a natural

process which acts to preserve and accumulate minor

advantageous variations within living systems.


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WHATISASPECIES?

The literal meaning of species is kinds.

Species is defined as a group of actually or potentiallyinterbreeding naturalpopulations, which are

reproductively isolated from other such groups(biologicalspecies concept).


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HOW IS REPRODUCTIVE ISOLATION BEETWEN

MAINTAINED?

Reproductive isolation is the existence of biological factors

(barriers) that impede two species from producing viable, fertile

offspring.

Hybrids are the offspring of crosses between different species.

Reproductive isolation can be classified by whether factors actbefore or after fertilization.


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7/32The 7th Group @Bio-B

PREZYGOTIC ISOLATING MECHANISMS

Geographic isolation. Species occur in different areas,separated by a physical barrier such as a river or mountain

range.



Ecological isolation. Species occur in the same area butoccupy different habitats. Survival of hybrids is low because they are

not adapted to either environment of their parents



Temporal isolation. Species reproduce in different seasons orat different times of the day.



Behavioral isolation. Species differ in their mating rituals.



Mechanical isolation. Structural differences between speciessuch as these copepods prevent mating between the sexes.



Prevention of gamete fusion. Gametes of one species usuallyfunction poorly with the gametes of another species, preventing the

formation of a zygote.



POSTZYGOTIC ISOLATING MECHANISMS



HOWDONEWSPECIESFORM?

Speciation is the process by which one species splits into two

species. Not all evolutionary changes result in new species. The critical

process in the formation of new species is the segregation of the gene

pool of the ancestral species into two separate gene pools.



ALLOPATRICSPECIATION

Allopatric speciation is thought to be the dominant form of

speciation among most groups of organisms. Allopatric speciation also may

result when some members of a population cross a barrier and form a new,

isolated population.



SYMPATRICSPECIATIONOCCURS

A partition of a gene pool that occurs without physical

separation is called sympatric speciation. The most common means of

sympatric speciation is polyploidy, an increase in the number of

chromosomes.


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WHAT CAUSES EXTINCTION?


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Habitat Destruction

Aerial photograph of dry forest scrub in

southern Zambia,

fragmented by agricultural land conversion. 2008

Habitat destruction elements include agricultural land conversion,

deforestation, overgrazing and urbanization; within these activities the

process of habitat fragmentation is a sometimes hidden cause of major

biodiversity loss.


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Overexplotation

Modern biotic extracts store in HongKong, China.

Certain of these products represent trade

in organisms that are endangered species.

Source: C. Michael Hogan

Overexploitation consists of intensive mineral and other geological

resource extraction, overharvesting of wild flora and fauna (mainly for

human food), hunting or fishing threatened fauna and killing of threatened

fauna for herbal or cultural extracts.


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POLLUTION

Pollution impacts include buildup of toxic atmospheric substances,

discharge of water pollutants into natural water reserves, chemical

contamination of soils and noise pollution.


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Introduction of Alien Species

The Signal crayfish has been introduced into

vast areas of Europe and Asia, where it has

decimated many native species.

Source: C.Michael Hogan

Introduction of alien species is usually an unintended activity whereseeds, stowaway fauna aboard ships and other viably reproducing biota are

transported by man to a new environment.


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DISEASEANDPARASITISM

The phenomena of disease and parasitism often weaken organisms

and interfere with metabolic function.


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Cryptic Habitats

Small geyser pool at Yellowstone NP, USA showing

a cryptic habitat inhabited by extremophile micro-

organisms. Source: C. Michael Hogan

A special problem arises in the case of cryptic habitats, defined asportions of an ecosystem that are largely hidden from normal investigative

view of scientists, or which have components that are not readily

discoverable with state of the art research techniques.


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EVOLUTIONARY CONNECTION

Evolution is a branch of biology

that studies the history of the origin of

species and the genetic relationship

between one of species with each other.


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LAMARCK'STHEORYOFEVOLUTION

Firstly, the idea of use and disuse.Secondly, the nature or acquired traits can be inherited fromthe environment to the offspring.


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LAMARCK'STHEORYOFEVOLUTION


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DARWIN'S THEORYOF EVOLUTION.

Firstly, the species living today are derived from

species that lived in the past.

Secondly, natural selection is the cause of adaptive

evolution.


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WALLACE'S THEORYOF EVOLUTION.

Developed a theory of natural selection which is basically

the same as that proposed by Darwin. Namely the competition

between intra-and inter-individual species or survival of the

fittest

.


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DARWINAND WALLACE'STHEORY

Natural selection is more profitable long neck giraffe. Long

neck giraffe can reach the high leaves, can survive while the short

neck can not do it.


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WEISMANN THEORYOF EVOLUTION

Evolution involves the inheritance of genes throughsex cells. This means that the evolution of the symptoms

associated with the natural selection of genetic factors.


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Th 7th G @Bi B

THE END. . .

Thanks your attention. . . .

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