ZOO-100 Module 1 Quiz

Course Information

• Course Code: ZOO-100
• Course Title: Amazing World of Animals
• Credits: 04 (3+1)
• Instructor: Dr. Sandesh Gawas
• Instructor's Credentials: Ph.D. Life Science-Zoology

Module 1: Origin, Diversity, and Distribution of Animals

• Topics covered:
  • Evolution of Earth, first living cell
  • Geological time line and animal evolution
  • Animal kingdom classification
  • Major animal habitats (desert, savanna, grassland, forest, cave, oceanic)
  • Paleozoology as an evolutionary tool

Evolution of Earth

• Speculation on Earth's origin spans thousands of years.
• Numerous hypotheses exist:
  • Nebular Hypothesis
  • Planetesimal Hypothesis
  • Tidal Hypothesis
  • Dust-Cloud Hypothesis
  • Nova Hypothesis
  • Binary-star Hypothesis

Nebular Hypothesis

• Proposed by Kant and Laplace in the 18th century.
• Describes solar system formation from a rotating nebula of gas and dust.
• Explains the formation of the Sun, planets, and other celestial bodies from a rotating cloud of gas and dust.
• Contraction of the cloud leads to spinning and flattening into a disk shape.
• The central region of the disk becomes the protosun, initiating nuclear fusion.
• Remaining material forms planetesimals.
• Planetesimals collide and accrete, forming larger bodies (protoplanets).
• Differentiation occurs, with denser materials sinking to the core and lighter materials to the mantle and crust.
• This process generates heat, leading to a molten interior.
• Objections:
  • Planets possess 98% of the solar system's rotational energy while the sun has 99.87% of the mass.
  • Earth's heavy elements require higher temperatures than those found in the sun.
  • Some satellites have retrograde orbits, and some rotate faster than their planet.

Planetesimal Hypothesis

• Proposed by Chamberlin and Moulton in 1895.
• Suggests that the solar system formed from a collision between the Sun and another star.
• The collision causes ejection of material from the sun's surface.
• Near-side ejections form larger planets.
• Far-side ejections form terrestrial planets.
• This material forms planetesimals that accrete to form planets.
• Objections:
  • Difficult to explain the massive passing star's proximity to the Sun.
  • Stars are too far apart for such alignment to occur.
  • Does not account for the differing sizes of the planets.

Tidal Hypothesis

• Proposed by James Jeans and Harold Jeffreys in 1917.
• Discusses a gaseous two-star Hypothesis.
• A passing star approaches the sun, creating tidal bulges and emitting a filament of gas.
• This filament condenses and forms the planets.
• Explains planet formation as a result of solar gas interactions.

Theories of Origin of Life

• Innate curiosity about life's origins has driven scientific inquiries.
• Understanding early Earth conditions is crucial.
• Multiple theories have been proposed:
  • Theory of Special Creation
  • Theory of Spontaneous Generation
  • Theory of Biogenesis
  • Theory of Eternity of Life
  • Theory of Catastrophism
  • Theory of Organic Evolution

Theory of Special Creation

• Based on religious or divine creation.
• States that each organism appeared independently in their present form.
• Supported by religious beliefs, not scientific evidence.

Theory of Spontaneous Generation

• Life arises from non-living matter.
• Proposed by ancient thinkers like Anaximander and Anaxagoras.
• Believed that some simple organisms originated in nonliving matter.
• Supported by observations of life emerging from decaying matter but lacked scientific basis.

Theory of Biogenesis

• Life originates from pre-existing life.
• Refutes spontaneous generation.
• Francesco Redi's experiments disproved spontaneous generation.
• Lazzaro Spallanzani disproved spontaneous generation using broth experiments under controlled conditions.
• Louis Pasteur further disproved it using swan-neck flask experiments.

Theory of Eternity of Life

• Life has always existed.
• Proposes that life can originate from other extraterrestrial sources or that life appeared under certain conditions when Earth was a molten mass.
• Has not been supported by scientific evidence

Theory of Catastrophism

• Explains extinction by catastrophic events.
• Suggests that life emerged after a cataclysmic event.
• Argues that life forms were wiped out and evolved in new ways based on what is needed.
• Belief that a catastrophe occurs and then life is repopulated by evolution.

Theory of Organic Evolution

• Life emerged gradually through a slow process of change.
• Organisms evolved from simpler forms.
• Theories of organic evolution are based on observation and the idea of natural selection.