AND THE ORIGIN OF L IFE

Evolution

THINKS TO KNOW

Keywords

Species

Reproductively isolated systems of breeding populations with similar morphology.

In simple terms; organisms, that look the same, that are able to breed and produce fertile offspring.

Adaptation & Mutation

Adaptation The evolutionary process whereby an organism

becomes better able to live in its habitat The change of an organism to be better suited to live

in its respective environmentMutation

Changes in the DNA caused by radiation, viruses and errors in DNA replication

A change in the DNA that causes a significant change in the organism’s phenotype or expressed traits

Common Decent, Ancestor & Descendant

Common Decent A group of organisms that share the same ancestor Organisms that descended from the same organism

Ancestor An earlier type A progenitor

Descendant A later evolutionary type The offspring of an earlier organism

Variation and Natural Selection

Variation The difference in characteristics typical of the group The difference between an organism’s traits and

another of the same speciesNatural Selection

The process where favorable traits become more common in each successive generation

The process where nature selects the traits that best suit the environment the particular organism lives in

Missing Link

The intermediate organism between arthropod apes and humans

Genetics, DNA & Genes

Genetics The study of the patterns of inheritance of specific

traitsDNA

Deoxyribonucleic acid Contains the genetic material for cell growth, division

and functionGenes

Segments of DNA that are located on the chromosomes

Controls the traits of an organism

RNA, Allele & Heredity

RNA Ribonucleic acid Single stranded

Allele One member of a pair of genes occupying a specific

part on the chromosome Can either be dominant of recessive

Heredity The passing on of traits from parent to offspring

Central Dogma, Nucleotides & Proteins

Central Dogma DNA is the carrier of genetic information in organisms.

Nucleotides Structural unit of DNA/RND Made up of a 5-carbon sugar, a 3-phosphate group and

one of 5 nitrogen bases; namely Adenine, Thymine, Guanine, Cytosine and Uracil

Proteins Chains of amino acids

Chromosomes & Genetic Drift

Chromosomes Organized structure of DNA and proteins Controls the expressed traits of an organism

Genetic Drift A change in allele frequency Can be caused by a change in the environmental

conditions or a change in the reproductive selection of the species

Phylogenetic Tree

A branching diagram showing inferred evolutionary relationship

Convergent and Divergent Evolution

Convergent Evolution Different organisms develop similar traits to serve

similar functions Butterfly and Bird. They developed wings for the same

purpose.

Divergent Evolution Similar organisms evolve to become more diverse until

they eventually become different species An population becomes separated and each separate

population adapts to a different niche and does so until they become two different species

WHO CONTRIBUTED TO THE THEORY

Scientists

Carolus Linnaeus (1707-1778)

Swedish NaturalistNested HierarchiesOrder of NatureSystema Naturae (1735)Father of TaxonomyOrganized from species

to kingdomTwo-part Name

Binomial Nomenclature

Carolus Linnaeus (1707-1778)

Influenced byPlato

Idealism and essentialismAristotle

Scala Naturae, The Great Chain of Being Organisms are arranged in increasing complexity

Judeo - Christian Creationism Species are individually designed and are permanent

Thomas Malthus (1766-1834)

English economist and clergyman“An Essay on the Principles of Populations”Food supply

ArithmeticPopulation growth

Geometric, logarithmic

Food supply limits population growth

Georges Cuvier (1769-1832)

French PaleontologistCatastrophism

A catastrophic event leads to extinctions of species that are replaced by distant migrating species

Earth’s age 4000 - 6000

Strongly opposed evolutionThe history of living organisms are recorded

in layers of as fossils

Jean Baptiste Lamarck

French naturalistEarly concepts of evolutionPhilosophie Zoologique (1809)

Desire to change Use and disuse Passing on of acquired traits

Species change over time into new species via natural processes

Charles Lyell

Scottish geologistPrinciples of Geology (1830)UniformitarianismGeological processes are so uniform that their

rates and effects must balance out

Influenced byJames Hutton (1726-1797)

Gradualism

Gregor Mendel (1832-1884)

Austrian MonkFather of geneticsProposed the laws of inheritanceUsed pea plants with different characteristics

Alfred Russel Wallace

British NaturalistStudied in the

Amazon Forest and in the Malaysian Isles

“On the Tendency of Varieties to Depart from the Original Type”

Charles Robert Darwin

English NaturalistStudied in the

Galapagos Islands“On the Origin of

Species by means of Natural Selection or the Preservation of Favored Races in the Struggle for Life”

PALEOEMBRYOANATOGEOCHEMISTRY

Evidences

Paleontology

Organisms evolved in a historical sequenceThe present id linked to the pastFossils form by chance and the quality variesFossil reconstruction requires a thorough

knowledge of AnatomyFossil

Preserved remains or traces of organismsDating rocks and fossils

Geological or relative dating (strata) Numerical or radiometric dating (isotopes)

Comparative Anatomy

Homologous Structures Features with different functions but similar structure

due to common ancestry Due to divergent evolution One species gives rise to many species that appear

different externally but are similar internallyAnalogous Structures

Similar in appearance and function but of different origins

Due to convergent evolution Different organisms develop similar structures to serve

the same purpose

Comparative Embryology

Closely related organisms often have similar stages or structure during early development

Similarities in early development should mean that similar genes are at work

This is like a heritage acquired from their common ancestor

Biochemistry

Similarity of the DNA between individuals determine their degree of relatedness

Based on the concept that similar proteins are based from the same DNA or a common genetic code creates the same protiens

Biogeography

Observations about marsupial distribution show that they are only found in America, Australia and New Guinea

Species were not distributed everywhere that they could survive

Islands have species endemic but are closely related to species on the mainland

The 5 Evidences for Evolution

Fossil Record Paleontology

Similarities in Body Structure Comparative Anatomy

Similarities in Early Development Comparative Embryology

Similarities in Chemical Compounds Biochemistry

Distribution of Species Biogeography

A G T C U

Genetics

Scientists

Rediscovered Mendel’s workHugo de VriesCarl CorrensErich von Tshermak-Seysenegg

Discovered the structure of DNAJames WatsonFrancis Crick

Nucleic Acids

Polymers made up of monomers called nucleotides

There are 2 kinds DNA – uses A, T, G, C RNA – uses A, U ,G, C

Stores and transmits information from one generation to another

Found in the nucleus of all cells

Proteins, Genes & Alleles

Protein Polymers made up of monomers called amino acids Workhorses of living systems

Gene A segment of DNA that codes for a particular trait The basic unit of heredity

Allele A particular form of a gene

Genetic Code

Set of rules by which information in DNA/RNA is translated into amino acid sequences

Red in groups of three called codons

Traits

There are two kinds of traitsSingle-gene trait

Only controlled by a pair of genes There are only two varieties Example, Presence of the widow's peak

Polygenic trait Controlled by numerous genes Has multiple varieties Example, Height.

Natural Selection as an Evolutionary Mechanism

Overproduction Each species produce more offspring than will survive to

maturityVariation

There is a variation of traits among the offspringCompetition

Organisms compete with one another for limited resources

Survival to Reproduce Individuals that passes the most favorable combination of

characteristics are most likely to survive and reproduce

Genetic Variation

Mutation Any change in the DNA sequence

Due to an error in DNA replication Due to environmental factors such as radiation

Gene Shuffling / Genetic Recombination Results from sexual reproduction

Genetic Drift When an allele becomes more common in a population

by chance Implies that all characteristics of an organism don’t have

to contribute to the fitness of the organism to be favored

Genetic Variation

Natural selection is not always necessary for genetic change to occur

Genetic variation is not controlled or directed toward a cause. When a variation does occur, natural selection goes to work

If a species has enough genetic variation for it to evolve quickly enough to keep up with the environment, it will survive; if not, it will become extinct

Ecology & Evolution

No two species can occupy the same niche in the same location for a long period of time This idea helps us understand how one species evolves

into many speciesSpeciation by Reproductive Isolation

Separation of populations stops interbreeding between the two

Separate populations adapt to different environments so the gene pool becomes dissimilar

The long separation eventually inhibits the interbreeding between the two populations permanently