evolution

EVOLUTION AND THE DIVERSITY OF LIFE

• Source of Evolution:

  • Evolution is the process of gradual change that results in the emergence of new species from older species.

  • It takes place over time, involving genetic differentiation and distribution.

  • Natural selection plays a key role, with all species descending from a single common ancestor.

• Carl Linnaeus:

  • Organised known species of organisms.

  • Naming of animals is done by identifying the genus and species, utilizing:

    • Binomial Nomenclature:

      • "Nomen" means name in Latin. Examples include:

        • Dog: Canis lupus familiaris (italicized for formal writing)

        • Cat: Felis catus domesticus

        • Corn: Zea mays

        • Human: Homo sapiens

• Mnemonic for Classification:

  • "DEAR KING PHILLIP CAME OVER FOR GOOD SOUP"

TENETS OF EVOLUTION BY NATURAL SELECTION

• Charles Darwin:

  • Observed diverse animal forms, noting deviations from original ancestors.

• Natural Selection:

1. Variation: Organisms exhibit genetic variation.

   • DNA is the genetic material encoding these variations.

2. Overproduction: More organisms are born than can survive due to limited environmental resources.

3. Non-random Survival:

   • Only those with variations that suit their environment survive, passing these traits to their offspring.

   • Variation can be skill-based or rooted in genetic makeup for survival.

4. Inheritance of Variations: Variations are transmitted to offspring.

5. Change in Gene Pool: The genetic makeup of a population changes over time.

6. Divergence into New Species: Given enough time, populations can diverge, leading to the formation of new species.

• Evolutionary Dynamics:

  • Individuals Do Not Evolve: Evolution reflects changes in the genetic composition of entire populations rather than individual organisms.

• Predictive Value of Natural Selection:

  • Evolution by natural selection does not possess predictive value; predictions cannot be controlled.

    • Example: Using Punnett squares is limited in evolutionary predictions.

  • Natural Process:

    • Evolution causes species to adapt and arise over time.

  • Biological Basis of Evolution:

    • All species originate through biological evolution, marked by changes in genetic material (DNA).

  • Species Concept:

    • Defined as an interbreeding group, with scientific naming conventions.

  • Genetic Changes and Mutation:

    • Change in DNA due to mutations can influence survival.

  • Population-Level Change:

    • Focus on the population as a unit that experiences genetic adaptation over time.

  • Natural Selection and Adaptation:

    • Concept of "survival of the fittest" highlights the mechanisms behind natural selection.

HUMAN EVOLUTION AND ADAPTATION

• Environmental Adaptation:

  • Early human ancestors evolved through genetic variations, enhancing adaptation to changing environments.

• Lifestyle Changes:

  • Evolutionary adaptations shaped human lifestyles, intelligence, and survival strategies.

Phylogenetic Relationships in Great Apes

• Hominidae Family:

  • Humans are classified within this family.

• Genetic Closeness:

  • Genetic evidence indicates that humans are closely related to chimpanzees, but they do not directly evolve from them.

    • There are no direct descendants; rather, a shared ancestor links them.

  • Hominins:

    • This refers to our group within evolutionary studies, emphasizing our lineage.