BSC2010-evolution-10-2024 (1)

Page 3: Outline of Contents

  1. Humans in the Tree of Life

  2. The Evolution of Primates

  3. The Evolution of H. sapiens

  • Selective Forces

  • Phenotypic Changes

  • Geography

  • Source: Scientific American, 2014

Page 4: Evolutionary Tree

  • Highlights of the evolutionary tree include:

    • Domains: Archeabacteria, Protists, Fungi, Plants, Animals

    • Various groups of life, such as echinoderms, chordates, arthropods, etc.

    • Includes ancient life forms like cyanobacteria and the molecular origin of life.

Page 5: Ancestry of Various Groups

  • Chordates: Includes echinoderms, arthropods, annelids, mollusks, etc.

    • Highlights the evolution from single-celled ancestors to complex multicellular organisms.

  • Key Lineages: Mammals, Birds, Reptiles, etc.

Page 6: Urochordates and Cephalochordates

  • Features shared by these organisms with other chordates include:

    • Notochord, dorsal hollow nerve cord, gill slits, post-anal tail

    • They first appeared in the fossil record > 500 MYA

Page 7: Characteristics of Mammals

  • Origin: Mammals arose > 175 MYA

  • Key Characteristics: Warm-blooded, different types of teeth, mammary glands.

Page 8: Adaptive Radiation of Primates

  • Occurred around 65 MYA, leading to groups including:

    • Lemurs

    • Prosimians

    • New World monkeys, Old World monkeys, Lesser apes, Great apes and humans

Page 9: Ancestry of Primates

  • Primates evolved from ancestral arboreal insectivores approximately 65 MYA

Page 11: Great Apes

  • Lineage:

    • Great apes lineage includes Gorillas, Orangutans, Gibbons, Humans, and Chimpanzees, evolved around 25 MYA.

Page 12: Environmental Changes

  • Refers to the Miocene epoch (23-5 MYA):

    • Environmental conditions transitioned from warm and wet to cool and dry, influencing evolutionary paths.

Page 14: Phylogeny of Hominidae

  • Timeline of hominids' evolution

    • H. neanderthalensis, H. sapiens, H. erectus, etc.

  • Split from other great apes about 5 MYA.

Page 15: Common Misconceptions

  • Not all ancestors of modern humans were chimps or any modern apes

  • Evolution is not a linear process; multiple human species coexisted and many led to evolutionary dead ends.

Page 19: Homo sapiens

  • Modern humans emerged around 200,000 years ago.

  • Key differences from Homo erectus include:

    • Smaller teeth and jaws

    • Smaller facial bones

    • Larger brain volume

    • Ability for symbolic thought

Page 21: Phenotypic Changes Through Time

  • Key Changes:

    • Mouth/Dentition

    • Brain Size

    • Bipedalism

    • Timeframe: 3-2.3 MYA to present (H. sapiens).

Page 24: Bipedalism

  • Evidence from Laetoli footprints traced back to 3.7 MYA.

Page 25: Reasons for Bipedalism

  • Provided energy-efficient locomotion, facilitated provisioning of offspring, food gathering, freeing hands, predator avoidance, and tracking migrations.

Page 26: Cultural Evolution

  • Intersections with biological evolution illustrated through technological progress:

    • Old Stone Age to Industrial Ages:

      • Key periods: Agricultural revolution, metal working.

Page 28: Key Dates for Exam

  • Important timelines include:

    • Adaptive radiation of primates

    • Origin of mammals

    • Rise of great apes (hominoids)

    • Emergence of hominids

    • Appearance of Homo sapiens.