Evolution Ad

8/3/2019 Evolution Ad

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Tema : orixe da vida. Experimento de Miller:

hipótese química



The Modern Theory of Evolution

Or neo-Darwinism



Early Theories of Evolution:

Lamark The more an animal

uses a particular part

of its body , thestronger and better

developed that part

becomes.

The characteristics

developed can be

passed on its offspring



Darwinv

s Theory of Evolution Darwin collected data on

many species between theyears 1831 and 1836 when

he took part in a scientificexpedition on board theship Beagle

Wallace had also the sameideas and published a a

paper together at 1858

The origin os species(Darwin) was published in1859

4 main points:

Overproduction and

variation

Competition and

adaptations

Natural selection Speciation



A pplying Darwin

v

s Theory



Darwinism today: Neodarwinism.

The rate of Evolution Genetics today explain the

variations and howheredity passes offspring

At present scientist do notagree on the rate at whichspecies formation occurs:

- slowly and continuously:

gradualism- short periods of rapidevolution and long periodof any changes:

punctuated equilibrium



Genetics and Evolution Modern biologists have combined Darwinvs

basic theory and population biology

Individuals do not evolve, their genes

remains the same throughout their lives.

However populations do evolve

Evolution es the gradual change of the allele

frequencies found in a population



Genetic sources of variation: how

a gene pool can change? Mutations

Genetic recombination: crossing over

between the paired chromosomes at meiosis

Migration into or out of a population

Genetic Drift: it is a change by change in

the gene pool of a small population



Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.

Crossing-over:

Para ver esta película, debedisponer de QuickTime y de

un descompresor TIFF (sin comprimir).

.



EVIDENCE OF EVOLUTION

STRUCTUR ALADAPTATIONS

± MIMICRY

± CAMOUFLAGE


http://evolution.berkeley.edu/evolibrary/home.phphttp://science.howstuffworks.com/animal-camouflage2.htm



EVIDENCE OF EVOLUTION

STRUCTUR ALADAPTATIONS

± MIMICRY

± CAMOUFLAGE

± MILLIONS OF YEARS

PHYSIOLOGICAL ADAPTATIONS

± CHA NGE IN A METABOLIC PROCESS

± WHAT DO YOU HEAR ABOUT IN THE NEWS ABOUT

SOME BACTERIA?




WHAT OTHER INDUSTRIES WOULD BE WORRIEDABOUT

RESISTA NCE?


http://evolution.berkeley.edu/evolibrary/home.php



OTHER EVIDENCE OF EVOLUTION

FOSSILS

A NATOMY

± HOMOLOGOUS STRUCTURES






FOSSILS

A NATOMY


± A NALOGOUS STRUCTURES






FOSSILS A NATOMY



± VESTIGIAL STRUCTURE

± EMBRYOS

WHAT ISA NOTHER EXAMPLE

OF VESTIGIAL STRUCTURES?






FOSSILS

A NATOMY



± VESTIGIAL STRUCTURE

± EMBRYOS BIOCHEMISTRY

± WHAT 2 THINGS?





Molecules reflect evolutionary divergence. You can see that the greater

the evolutionary distance from humans (yellow cladogram), the greater the

number of amino acid differences in the vertebrate hemoglobinpolypeptide.







A phylogenetic tree of living hominoids based

on DN A-DN A hybridization data





Aphylogenetic treeThis tree shows the relationship

between 20 species of eukaryotes. The numbersrepresent the minimum number of nucleotide substitutions in thegene for cytochrome c needed to

produce these 20 proteins from aseries of hypothetical ancestralgenes at the various branchingpoints (nodes). Cytochrome c isan ancient molecule, and it hasevolved very slowly. Even after more than 2 billion years, one-third of its amino acids areunchanged. This conservatism isa great help in working out theevolutionary relationshipsbetween distantly-relatedcreatures like fish and humans.



Types of Natural Selection (deer mice)

In a vivid illustration of natural selection at work, scientists at Harvard University have

found that deer mice living in Nebraska¶s Sand Hills quickly evolved lighter coloration after glaciers deposited sand dunes atop what had been much darker soil. The work is described

this week (Aug. 27) in the journal Science.



Directional selection: individuals with

more extreme values for a trait have greater fitnessresult: directional

change in the traite.g., Darwin's Finchesgo to:http://www.bio.georgiasouthern.edu/bio-

home/harvey/lect/lectures.html?flnm=nsln&ttl=Population%20change%20and%20natural%20selection&ccode=el&mda=scrn



Stabilizing selection:Most common (average) phenotype is

most stabilizing because it eliminates extremes example: human

birth weight The graph is based on infants born in London from 1935 to 1946. From Karn andPenrose (1951).



Disruptive (diversifying):

occurs when extreme individuals aremore fit, it diversifies the population







Sexual selection Darwin realized that not all traits

could be explained by natural selectionsome traits enhance

mating success, even at the expense of survivaldefinitionsexual selection favors traits that improve

the mating success of the individualin most animals,operates most intensely among males





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Intrasexual selectionFavors traits that dealwith conflict between individuals of the

same sex



Intersexual selection (mate choice) Favors traits that enhanceattractiveness to the opposite sexresult:ornaments (plumes, wattles,bright color, songs, symmetry, etc.) - apparently these "attractive"

features are preferred by the opposite sex; why?



Speciation: allopatric &

sympatric



Allopatric or Sympatric?



Is it likely that both populations would continue to evolve

in the same way? Why or why not?Are they different

species at thi s point?



And the consequence of speciation are well

documented in the fossil record:



Convergent evolution: natural selection causes that

unrelated species to resemble one another



Coevolution: 2 or more species

can evolve in response to eachother It reduces competetion

between species and benefits both species

An example of Antagoni stic Coevolution is Papiliomachaon caterpillar whichlives on Ruta chalepensisplant. Rue plant producesetheric oils which repelplant-eating insects. Thecaterpillar developedresistance to thesepoisonous substances, thusreducing competition of other plant-eating insects.



Some good examples of natural

selection:Deer mouse & peppered moth





El experimento llevado a cabo por Luria y Delbrück

(1943) sugiere que el fago T1 selecciona a

las bacterias que ya son previamente resistentes yno induce su aparición



A

rtificial Selection

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