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.