1. Phylum
    2. 1. Classification of Animals
    2. Protozoa
    3. Porifera
    4. Coelenterata
    5. Platyhelminthes
    6. Nemathelminthes
    7. Annelida
    8. Earthworm
    9. Arthropoda
    10. Cockroach
    11. Mosquito
    12. Honey bee and Silk moth
    13. Mollusca
    14. Echinodermata
    15. Hemichordata
    16. Chordata
    17. Pisces
    18. Amphibia
    19. Frog
    20. Reptile
    21. Aves
    22. Mammalia
    23. Rabbit bone
  2. Animal Behaviour and Adaptation
    3. 24. Animal behaviour
    25. Animal adaptation
    26. Migration
  3. Developmental Biology
    4. 27. Development of Animals
    28. Development of Frog
  4. Human Biology
    5. 29. Tissues
    30. Sense organs
    31. Digestive system
    32. Circulatory system
    33. Respiratory system
    34. Nervous system
    35. Endocrine system
    36. Reproductive system
    37. Excretory system
    38. Skeletal system
    39. Basic concept of Immunology
    40. Human diseases
  5. Evolutionary Biology
    6. 41. Origin of Life
    42. Organic Evolution
    43. Theories of Evolution
    44. Evolution of Human beings
    45. Horse Evolution
Evolutionary Biology
42. Organic Evolution
INTRODUCTION
Term
The term ‘evolution’ (L., evolvere = to unfold or unroll) was introduced by English philosopher, Herbert Spencer (1820-1903).
Definition
Biological (organic) evolution is the change in the properties of groups of organisms over the course of generations.
Study
Evolutionary Biology is the study of history of life forms on Earth.
Central Theme
‘Descent with modification’ is the central theme of evolution.
Scope
Organic evolution deals with changes in the properties of population of organisms from time to time.
Hypothesis
Evolution is an excellent working hypothesis to approach the problem of diversity of organisms.
Process
The process of evolution is continuous, taking place even now.
Quote
Theodosius Dobzhansky: 'Nothing in biology makes sense except in the light of evolution'.
Postulates
  1. Organisms that appeared earlier were simpler
  2. Earlier simpler organisms have gradually changed into existing complex forms
  3. All organisms are interrelated because of common origin
EVIDENCES
Taxonomy
Definition
Taxonomy is the science of classification of organisms
Common Characteristics
Members of each taxonomic group posses some common characteristics due to common ancestry
Complexity
Categorization of animals in increasing complex form provides obvious evidence of evolution under taxonomy
Phylogenetic Tree
Scheme of classification provides a proof of descent from a common ancestor
Biogeography
Definition
Study of geographic distribution of plants and animals
Biogeographical Realm
Region characterized by a distinct biota
Regions
Palaeartic
Europe and Asia north of the tropics, north-western corners of Africa
Nearctic
North America exclusive of the tropics
Neotropical
Central America including low lands of Mexico, Islands of the Caribbean and all of South America
Ethiopian
Africa (with exception of the Atlas Mountains), Madagascar and adjacent islands
Oriental
Tropical part of Asia, south of the Himalaya Mountains
Australian
Australia, Tasmania, New Guinea and islands east of Borneo
Separated Regions
Palaearctic and Oriental regions separated by high mountain ranges
Prototherians
Most primitive mammals found in Australia
Adaptive Radiation
Production of ecologically diverse species from a common ancestral stock (e.g., marsupials in Australia)
Parallel Evolution
Evolutionary change where marsupials resemble equivalent placental mammals
Galapagos Islands
Description
'A living laboratory of evolution', named after giant tortoises
Darwin's Finches
13 species showing adaptive radiation in beak shapes and sizes
Comparative Anatomy
Tectology
Study of functional anatomy
Types
  1. Homology and Homologous organs
  2. Analogy and Analogous organs (e.g., Sting gland of Honey bee and Scorpion)
  3. Vestigial organs
  4. Connecting Links
  5. Atavism
Atavism Examples
  1. Large canines
  2. Thick body hairs ('Lion's boy' of Russia)
  3. Monstral face
  4. Short temporary tails
  5. Gill slits
  6. Multiple nipples
Comparative Embryology
Principle
Common patterns of development provide evidence of evolution
Von Baer
Basic rules of embryonic development
Biogenetic Law
Ernst Haeckel: 'Ontogeny recapitulates phylogeny'
Examples
  1. Tadpole larva resembles fishes
  2. Gill clefts in vertebrate embryos
Physiology and Biochemistry
Molecular Evidence
Comparisons of DNA, RNA or proteins evaluate evolutionary relationships
Examples
  1. Uniform occurrence of enzymes (trypsin, amylase)
  2. Thyroxine effectiveness across vertebrates
  3. Amino acid configuration of cytochrome C (Dickerson, 1972)
  4. Precipitation test (Nuttall, 1904)
Palaeontology
Definition
Study of fossils (direct evidence of evolution)
Types
  1. Palaeobotany (fossil plants)
  2. Palaeozoology (fossil animals)
Fossil Types
  1. Petrifaction (bones, shells, teeth)
  2. Moulds
  3. Casts
  4. Compressions
  5. Coprolites (preserved intestinal contents)
  6. Palynofossils (spores, pollen)
  7. Pseudofossils (mineral patterns)
Notable Finds
  1. 20 million year old fossil forest (Birbal Sahni Institute)
  2. 25,000 year old frozen mammoths in Siberia
Pioneers
  1. Leonardo da Vinci (Father of Palaeontology)
  2. Georges Cuvier (Father of Modern Palaeontology)
Dating Methods
Radioactive Clock
Introduced by Boltwood (1907)
Radiometric Dating
  1. William F. Libby (Nobel 1960 for Carbon-14 dating)
  2. Half-life: 5568 years for C-14 → N-14 (useful up to 70,000 years)
  3. Potassium-Argon method (for hominid fossils)
  4. Electron-Spin Resonance (ESR, Zeller 1967 - most accurate)
GEOLOGICAL TIME SCALE
Era
Period
Epoch
Years Ago
Major Biological Events
Precambrian
4.6 billion
Origin of Earth
3.5 billion
First prokaryotes appear
2.5 billion
Oxygen accumulates in atmosphere
1.5 billion
First Eukaryotes appear
0.7 billion
Origin of first animals
Palaeozoic
Cambrian
0.57 billion
Origin of most invertebrate phyla
Ordovician
0.52 billion
First fish (Ostracoderm)
Silurian
0.45 billion
First jawed fish; land colonization
Devonian
0.42 billion
Age of fishes; Origin of Amphibians
Carboniferous
0.375 billion
Age of Amphibians; Origin of Reptiles
Permian
0.285 billion
Radiation of reptiles
Mesozoic
Triassic
0.240 billion
First dinosaurs and mammals
Jurassic
0.195 billion
First bird (Archaeopteryx)
Cretaceous
0.135 billion
Extinction of Dinosaurs
Coenozoic
Palaeogene
Palaeocene
65 million
Primitive primates appear
Eocene
57 million
Origin of horse
Oligocene
34 million
Monkey-like primates appear
Neogene
Miocene
23 million
Radiation of Mammals
Pliocene
5 million
First hominids appear
Pleistocene
1.8 million
Man evolved
Holocene
0.01 million
Age of Man
CONTENT
Extinct Reptiles
  1. Ichthyosaurs (fish-like)
  2. Pterosaurs (bird-like flying)
Best Fossil Record
Horse
AGES
Stone Age
  1. Paleolithic
  2. Mesolithic
  3. Neolithic
Bronze Age
Iron Age
KEY TERMS
Term
Coined/Used by
Evolution
Spencer
Organic evolution
Charles Darwin (theory by Lamarck)
Founder of Evolution concept
Empedocles
Father of Evolutionary concept
Buffon
Prebiotic soup
Oparin
Coacervates
Oparin
Hot dilute soup
Haldane
Protenoid microspheres
Sydney Fox
Natural selection
Darwin
Survival of the fittest
Spencer
Concepts
  1. Nucleic acids - Most important for Origin of Life
  2. Protobiont components: Amino acids + Sugar + Glycerol + Fatty acid
  3. Microsphere - Protobiont made of Polypeptides
  4. Liposomes - Protobiont made of Lipids
  5. Coacervates - Protobiont made of Polypeptide + Nucleic acid + Polysaccharide
  6. Pre-cell - Coacervate with nucleoprotein and surface membrane
Laws
Dollo's Law
Evolution is irreversible
Parallelism
Adaptive convergence of closely related groups
Discontinuous Distribution
Organisms present at different places without traces in between
Miscellaneous
  1. Process of evolution is continuous
  2. Darwin's finches evidence from Biogeography
  3. Cladistics - Study of evolutionary branches
  4. Phylogeny - Study based on homologous development