Biological Diversity and Evolution Notes

Our Solar System

  • Relative size and interesting facts for all known objects over 1500 km in diameter.
  • Positions not to scale; approximately true color.
    • Sun
      • Main sequence star.
      • The Sun's hot plasma twists its powerful magnetic field into knots, causing sunspots and intense solar flares.
    • Planets (in order from the sun)
      • Mercury
        • Terrestrial planet.
        • Mercury rotates so slowly that sunrise to sunset lasts a full Mercury year (about 88 Earth days).
      • Venus
        • Terrestrial planet.
        • Venus's thick CO2CO_2 atmosphere and sulfuric acid clouds trap heat like a greenhouse: its surface is hot enough to melt lead!
      • Earth
        • Terrestrial planet.
        • On this tiny planet, alone in the vastness of space, every person you've ever loved has lived out their lives.
      • Mars
        • Terrestrial planet.
        • The ice caps of Mars grow a layer of dry ice each winter. In spring it turns back into CO2CO_2 gas, causing 400 km/h winds and global dust storms.
      • Jupiter
        • Gas giant planet.
        • Jupiter's ammonia cloud bands include the Great Red Spot, a vast vortex storm that has persisted for hundreds of years.
      • Saturn
        • Gas giant planet.
        • The rings of Saturn consist of innumerable small clumps of ice and dust orbiting the planet together.
      • Uranus
        • Gas giant planet.
        • The axis of rotation of Uranus is tilted sideways, probably due to a collision with an Earth-sized object soon after it formed.
      • Neptune
        • Gas giant planet.
        • Neptune has very active weather systems, including the strongest sustained winds in the solar system: up to 2100 km/h.
      • Pluto
        • Dwarf planet - Kuiper belt.
        • Pluto's elliptical orbit sometimes brings it even closer to the Sun than Neptune.
      • Eris
        • Dwarf planet - Scattered disk.
        • Eris is covered in ices; it partly thaws when it nears the Sun every 557 years.
    • Other Objects Mentioned
      • Asteroid Belt
      • Kuiper Belt
    • Moons
      • Moon (of Earth)
        • Probably formed when a Mars-sized object collided with the early Earth.
      • Largest Moons of Jupiter
        • Io: Over 400 active volcanoes due to Jupiter's gravity.
        • Europa: Has an ocean of liquid water under its ice crust.
        • Ganymede: So large that it creates its own magnetic field.
        • Callisto: Stable surface and low radiation due to its wide orbit.
      • Largest Moons of Saturn
        • Iapetus: A 13 km high ridge runs halfway around its equator.
        • Titan: Has rivers, lakes, and rain made of liquid natural gas.
        • Rhea: Giant ice cliffs from tectonic activity streak its surface.
      • Largest Moons of Uranus
        • Titania: Enormous canyons: one goes nearly from equator to pole.
        • Oberon: Its ancient surface is almost entirely covered with craters.
      • Triton (A moon of Neptune)
        • Orbits backward and has geysers of liquid nitrogen.
      • Charon (A moon of Pluto)
        • Charon and Pluto itself mutually orbit a point between the two.
      • Ceres
        • Dwarf planet – Asteroid belt.
        • Ceres contains of the mass of the entire asteroid belt.

Principles of Biology and Biological Hierarchies

  • Sun and planets impose gravitational forces on each other.
    • It is the mass difference that makes them distinct; a planet with small mass is restrained more by the sun.
    • There is an integration where an entity at a level constrains members at a lower level (Sun ↔ planets ↔ moons).
  • Cells are held together by a greater density of covalent and hydrogen bonds of tissue features than these tissue features are held together by organ features, and organ features are held together by organismal features.
    • In a cellular system, there are different hierarchical levels. These levels define complexity.

Hierarchical Units in Biology

  • Atoms: Smallest unit of most chemical compounds.
    • Example molecules found ``` Carbohydrate, Protein, DNA
  • Cell: Basic biological unit.
    • Example ``` Epidermal cell, Parenchyma cell, Blood cell
  • Tissue: A group of similar cells.
    • Example ``` Muscle tissue, Nerve tissue
  • Organ: A structure composed of different tissues.
    • Example ``` Liver, leaf, eye
  • System: Functional unit made up of correlated and semi-independent parts.
    • Example ``` Digestive system, Photosynthetic system
  • Organism: Any living thing.
    • Example ``` Animal, Plant, or a microbe
  • Population or Colony: Similar individual organisms (species) in a specific locality.
    • Example ``` Asiatic Lion population in Gir forests of Gujarath, India; E. coli population in the mouth
  • Biome: Major regional community of organisms defined by the habitat and determined by the interaction of the substrate, climate, flora, and fauna.
    • Example ``` Grassland biome, Desert biome, Ocean biome
  • Ecosystem: A collection that includes all the biotic organisms and abiotic components of the total environment.
    • Example ``` Marine ecosystem, Himalayan ecosystem
  • Biosphere: The part of Earth that contains all the ecosystems.
    • Example ``` Earth

Features of Biological Hierarchy

  • Atoms ↔ Molecules ↔ Cells ↔ Tissues ↔ Organs ↔ System ↔ Organism
    • Constrains imparted by each component.
    • Biological hierarchy can undergo decomposition similar to many systems.
      • One can pick a leaf (organ) off a shoot (organ system) without destroying the lower-level leaf tissues.
      • Applying a little perturbation energy removes the top levels; as energy increases, progressively lower levels are uncoupled.
    • Structure and function are correlated at all levels of biological organization.
      • Structural hierarchy is simpler and can be explained by the forces operating within the system.
      • Functional hierarchy is constrained by the mental state regulated by the nervous system.
      • Example: Feeling energetic after consuming a soft drink due to sugar supply influencing cells, particularly intestinal cells.
  • Living hierarchies are composed of sub-hierarchies.
    • Atoms are built into macromolecules like enzymes (chemical sub-hierarchy).
    • Macromolecules self-assemble into cells (cellular sub-hierarchy).
    • Cells differentiate into organisms (specialization sub-hierarchy).
    • Organisms form populations by mating patterns (evolution sub-hierarchy).
    • The coordinated actions of constrained parts fitting together toward a complex goal.
      • A painter begins a part of his whole painting, later elaborating according to the relative size and orientation of the first part.
  • Novel properties appear at each level of the biological hierarchy as a result of interactions among components at the lower levels.

Principles of Biology

  • Biology is a very complex subject due to many levels of hierarchies and interactions (regulations).
    • To study biology, we need to understand what is happening inside at each hierarchical level, also considering the surrounding physical, chemical, and biological environment.

Key Biological Principles

  • Survival and Reproduction as the primary goal.
    • Reproduction is most important because the ultimate goal is that genetic material survives for the next generation.
    • The more genetic code similarity, the more willingness to share and vice versa.
  • Evolving: Changes occur in living things gradually.
  • Reproductive Advantage
    • Territorial Behavior: Animals defend territory to increase reproductive advantage.
    • Natural selection has favored the evolution of behaviors that maximize the reproductive success of males and females.
      • By evaluating and selecting mates with superior qualities, an animal can increase their reproductive success.
  • Life is redundant: The redundant structures and processes of life enable it to face environmental challenges.
  • Co-existence: Living things adapt themselves for co-existence.
  • Genes are passed from one generation to the next.
    • Pattern baldness results from an autosomal gene that is thought to be dominant in males and recessive in females.
  • Cost: Each distinguishing biological trait is made valuable by its cost.
  • Interactions of genes and environment: The expression of some genotypes depends on specific environments.
    • Example: Himalayan rabbits reared at different temperatures.
      • Reared at 20°C or less
      • Reared at temperatures above 30°C
  • Life is conservative: A new species is the modification of an existing system.
  • Simple building blocks of living things
    • Polymer - Monomer - Function
      • Polysaccharides - Sugars - Store house of energy
      • Proteins - Amino acids - Provide cells structure and perform cellular tasks
      • Nucleic acids - nucleotides - Carry genetic information
  • Extremes: Life will exploit its environment to the maximum extent possible.
    • Example ``` Thermophilus aquaticus

Summary of Principles

  • The primary goal of life is survival and reproduction.
  • Living things are constantly changing: Evolving.
  • Long-term changes occur in a species only if there is a reproductive advantage.
  • Life is redundant.
  • Co-existence of species requires that each adapts to a different ecological niche.
  • Attributes passed from one generation to the next require an information legacy: Genetics.
  • Each distinguishing biological trait is made valuable by its cost.
  • An individual is a product of both its genetic code and its environment - Interaction.
  • Life is conservative.
  • Living things use simple building blocks with complex interactions – diversity and commonality.
  • Extremes are not tolerated well by living things, nor do living things create extreme conditions.