BI 5103 FISIOLOGI TERINTEGRASI (Integrative Physiology)

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BI 5103

FISIOLOGI TERINTEGRASI (Integrative Physiology)

Core Principle 1: EVOLUTION (Konsep Inti I : Evolusi)

Semester I 2013/2014 tjandraanggraeni 1

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Why Evolution?

 Evolusi dapat memberikan penjelasan

secara scientific pada sejarah kehidupan di bumi dan mekanisme yang menyebabkan terjadinya perubahan pada kehidupan

 (Evolution provides a scientific

explanation for the history of life on Earth and the mechanisms by which changes to life have occurred)

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A flower mantid

in Malaysia

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A leaf mantid in Costa Rica

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Sub Topik :

1. Evolusi melalui seleksi alam : asal-usul organisme dan fungsi fisiologisnya

2. Evolusi menjelaskan asal hubungan antara struktur dan fungsi

3. Variasi dalam struktur protein yang mendasari fungsi fisiologis pada tingkat molekuler dikendalikan oleh mekanisme evolusi

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1. Evolusi melalui seleksi alam : asal- usul organisme dan fungsi

fisiologisnya

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Natural Selection

 Darwin’s theory

 Mechanism:

 Variation in populations

 Some variation heritable

 More individuals born than will survive

 Adaptation

EVOLUTION:

Natural selection & development of complex life

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The evolution of insecticide resistance is an example of natural selection in action

Chromosome with gene conferring resistance to insecticide

Additional

applications of the same insecticide will be less effective, and the frequency of resistant insects in the population will grow

Survivor

Insecticide application

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Terminal

bud Lateral buds

Leaves

Kale

Stem

Brussels sprouts

Cauliflower Cabbage

Kohlrabi Wild mustard

Flower clusters

Flowers

and stems

Broccoli

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Dogs varieties

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 Linnaeus used physical appearance to identify

species when he developed the binomial system of naming organisms

◦ This system established the basis for taxonomy

CONCEPTS OF SPECIES

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 But appearance alone does not always define a species

– Example: eastern and western meadowlarks (the songs of the two species are different)

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 Similarities between some species and variation within a species can make defining species

difficult

– Humans exhibit extreme physical diversity

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 The biological species concept defines a species as

– a population or group of populations whose members can interbreed and produce fertile offspring

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 A ring species may illustrate the process of speciation

OREGON POPULATION 1

2 COASTAL

POPULATIONS

Yellow- eyed

Monterey

3

Sierra Nevada

Yellow- blotched Gap in

ring Large-

blotched

INLAND

POPULATIONS

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2. Evolusi menjelaskan asal hubungan antara struktur dan fungsi

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Humerus Radius Ulna Carpals

Metacarpals Phalanges

Human Cat Whale Bat

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◦ Comparative embryology is the comparison of early stages of development among different organisms

– Many vertebrates have common embryonic structures, revealing homologies

– When you were an embryo, you had a tail and pharyngeal pouches (just like an embryonic fish)

A mass of other evidence reinforces the

evolutionary view of life

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Pharyngeal pouches

Post-anal tail

Chick embryo Human embryo

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 Some homologous structures are vestigial organs

– For example, the pelvic and hind-leg bones of some modern whales

A mass of other evidence reinforces the

evolutionary view of life

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Pelvis and hind limb

Rhodocetus (predominantly aquatic) Pakicetus (terrestrial)

Dorudon (fully aquatic)

Balaena (recent whale ancestor) Pelvis and

hind limb

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Mechanisms of respiration : example

 Aquatic animal : diffusion through skin or gills

 Terrestrial animal : diffusion through

alveolus in lungs

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Ikan

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Serangga

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Burung

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Amphibi

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Mamalia

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Manusia

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3. Variasi dalam struktur protein yang mendasari fungsi fisiologis pada tingkat molekuler dikendalikan oleh

mekanisme evolusi

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CONTROL OF GENE EXPRESSIONS

PROTEIN

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Prokaryotic cells

Proteins interacting with DNA turn

prokaryotic genes on or off in response to environmental changes

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DNA

RNA polymerase cannot attach to promoter

Lactose-utilization genes Promoter Operator

Regulatory gene

OPERON

mRNA

Active repressor

Operon turned off (lactose absent)

Protein

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DNA

Protein

Inactive repressor

Lactose Enzymes for lactose utilization

RNA polymerase bound to promoter

Operon turned on (lactose inactivates repressor)

mRNA

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DNA

Inactive repressor

Active repressor

Inactive repressor

Active repressor

Lactose Promoter

Tryptophan Operator Gene

lac operon trp operon

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Eukaryotic cells

 Differentiation results from the

expression of different combinations of genes

◦ Differentiation involves cell specialization, in both structure and function

◦ Differentiation is controlled by turning specific sets of genes on or off

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Muscle cell Pancreas cells Blood cells

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Multiple mechanisms regulate gene expression in eukaryotes

◦ Many possible control points exist; a given gene may be subject to only a few of these

– Chromosome changes (1)

– DNA unpacking

– Control of transcription (2)

– Regulatory proteins and control sequences

– Control of RNA processing

– Addition of 5’ cap and 3’ poly-A tail (3) – Splicing (4)

– Flow through nuclear envelope (5)

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Multiple mechanisms regulate gene expression in eukaryotes

◦ Many possible control points exist; a given gene may be subject to only a few of these

– Breakdown of mRNA (6) – Control of translation (7) – Control after translation

– Cleavage/modification/activation of proteins (8) – Breakdown of protein (9)

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NUCLEUS

DNA unpacking

Other changes to DNA

Addition of cap and tail Chromosome

Gene

RNA transcript

Gene Transcription

Intron Exon

Splicing

mRNA in nucleus Cap

Tail

Flow through

nuclear envelope

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Broken- down mRNA CYTOPLASM

Breakdown of mRNA

Translation mRNA in cytoplasm

Broken- down protein Cleavage / modification /

activation

Breakdown of protein Polypeptide

Active protein

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Cascades of gene expression direct the development of an animal

◦ Role of gene expression in fruit fly development

– Orientation from head to tail

– Maternal mRNAs present in the egg are translated and influence formation of head to tail axis

– Segmentation of the body

– Protein products from one set of genes activate other sets of genes to divide the body into segments

– Production of adult features

– Homeotic genes are master control genes that determine the anatomy of the body, specifying structures that will develop in each segment

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Head of a normal fruit fly Antenna

Eye

Head of a developmental mutant

Leg

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Egg cell

within ovarian follicle

Follicle cells

“Head”

mRNA

Protein signal Egg cell

Gene expression

1

Cascades of

gene expression

2

Embryo

Body

segments

Adult fly

Gene expression

3

4

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Signal transduction pathways convert messages received at the cell surface to responses within the cell

◦ Signal transduction pathway is a series of

molecular changes that converts a signal at the cell’s surface to a response within the cell

– Signal molecule is released by a signaling cell

– Signal molecule binds to a receptor on the surface of a target cell

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Signal transduction pathways convert messages received at the cell surface to responses within the cell

– Relay proteins are activated in a series of reactions – A transcription factor is activated and enters the

nucleus

– Specific genes are transcribed to initiate a cellular response

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Signaling cell

DNA

Nucleus Transcription factor

(activated)

Signaling

molecule Plasma membrane Receptor

protein

Relay proteins

Transcription mRNA

New protein

Translation Target cell

2 1

3

4

5

6

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 Homeotic genes

 are called master control genes and

 determine basic features, such as where pairs of wings or legs develop on a fruit fly.

 Profound alterations in body form can result from

 changes in homeotic genes or

 how or where homeotic genes are expressed.

Genes that control development play a major role in evolution

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 Duplication of developmental genes can also be important in the formation of new morphological features.

 A fruit fly has a single cluster of homeotic genes.

 A mouse has four clusters of homeotic genes.

 Two duplications of these gene clusters occurred in the evolution of vertebrates from invertebrates.

Genes that control development play a major role in evolution

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 In the threespine stickleback fish, those fish that that live

 in the ocean have bony plates and a large set of pelvic spines but

 in lakes have reduced or absent bony plates and pelvic spines, resulting from a change in the expression of a developmental gene in the pelvic region.

Genes that control development play a major role in evolution

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Figure 15.11C

Missing pelvic spine

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 In most cases, complex structures evolve by

increments from simpler versions with the same basic functions.

 In the evolution of an eye or any other complex structure, behavior, or biochemical pathway, each step must

 bring a selective advantage to the organism possessing it and

 increase the organism’s fitness.

Evolutionary novelties may arise in several ways

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 Mollusc eyes evolved from an ancestral patch of photoreceptor cells through a series of incremental modifications that were adaptive at each stage.

 A range of complexity can be seen in the eyes of living molluscs.

 Cephalopod eyes are as complex as vertebrate eyes, but arose separately.

Evolutionary novelties may arise in several ways

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Figure 15.12

Patch of pigmented cells Pigmented cells (photoreceptors)

Eyecup Pigmented

cells

Simple pinhole eye

Fluid-filled cavity

Eyecup Nerve

fibers

Nerve fibers

Optic nerve

Lens

Retina Layer of

pigmented cells (retina)

Optic nerve Eye with

primitive lens Transparent protective

tissue (cornea)

Optic nerve

Cornea Complex camera lens-type eye

Squid Marine snail

Nautilus Abalone

Limpet

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 Adaptations that have evolved in one

environmental context may be able to perform new functions when conditions change

◦ Example: Plant species with

catch basins, an adaptation to dry environments

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Medium ground finch

Cactus ground finch

Small tree finch

Large

ground finch

Small

ground finch

Large cactus ground finch

Sharp-beaked ground finch

Vegetarian finch

Seed eaters

Ground finches

Cactus flower eaters

Bud eaters

Tree finches

Insect eaters Medium tree finch

Large tree finch

Mangrove finch

Woodpecker finch

Green

warbler finch

Gray

warbler finch

Warbler finches

Common ancestor from South America mainland

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 A phylogenetic tree based on molecular data

Pleistocene Pliocene

MioceneOligocene

Brown bear Polar bear

Asiatic black

bear

American black

bear

Sun bear

Sloth bear

Spectacled bear

Giant panda

Raccoon

Lesser panda

Ursidae

Procyonidae

Common ancestral carnivorans

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