Ultimate Family Tree: The Evolutionary Tree of Life

Introduction

• Presented by Matt Baker, known for family trees.
• Focus on the ultimate family tree connecting all living things: the evolutionary tree of life.
• For copies, visit useful charts.com.

LUCA: Last Universal Common Ancestor

• LUCA is the single-celled organism from which all living things descended.
• Includes bacteria and archaea (ARA).
• Origins of LUCA and its ancestors fall outside the theory of evolution; related concepts: abiogenesis.

Viruses

• Placed outside the main tree; unclear relationship to life.
• Differences between life and viruses:
  • Life can reproduce independently.
  • Viruses require a living host to replicate.
• Categorized into three realms:
  • Duplo DNA viira: Double-stranded DNA viruses (e.g., herpes).
  • VAR DNA viira: Various DNA viruses (e.g., smallpox).
  • Ribbo viira: RNA-based viruses (e.g., common cold, flu, COVID).

Evolutionary Domains

• Initial thought: life evolved in three domains (bacteria, eukarya, ARA).
• Current theory: Two domains: bacteria and ARA; eukarya evolved from ARA.

Bacteria

• Familiar single-celled organisms; cause diseases (e.g., streptococcus, staphylococcus).
• Includes Basiliaphi and Pseudomonadota (e.g., E. coli, bubonic plague).
• Good bacteria: probiotics (e.g., Lactobacillus).

ARA (Archaea)

• Distinct from bacteria; includes extremophiles (thermophiles, halophiles).
• Proposed Asgard superphylum - potential origin of eukaryotic cells.

Eukaryotic Cells

• Larger, complex cells with organelles (e.g., nucleus, mitochondria).
• Evolved via endosymbiosis (bacteria entering eukaryotic cells).
• Early forms: amoebas, brown algae, etc.

Classification of Life Forms

• Eukaryotic life forms were previously classified into a fourth kingdom (protists); current classification is still under debate.
• Fungi are more closely related to animals than plants.
• Early animal forms included sponges and corals, leading to bilateral symmetry and nervous systems.

Animal Evolution

Protosome vs. Deuterostome Branches

• Protosomes: Mouth forms first (e.g., flatworms, insects).
• Deuterostomes: Anus forms first (e.g., chordates, vertebrates).

Insects

• Evolved from early arthropods; significant varieties (e.g., hexapods).
• Insects undergo metamorphosis (e.g., holometabolous insects).

Chordates (Vertebrates)

• Include lancelets and vertebrates with backbones.
• Early vertebrates had cartilage skeletons; later evolved bony skeletons.
• Two main fish types: ray-finned and lobe-finned fish.

Transition to Land

• Lobe-finned fish are ancestors of land vertebrates (tetrapods).
• Tiktaalik: Fossil evidence of fish-like tetrapods.

Amphibians and Amniotes

• Early tetrapods diversified into amphibians and amniotes.
• Amniotes developed protective eggs, allowing reproduction away from water.

Synapsids vs. Diapsids

• Synapsids led to mammals; diapsids led to reptiles and birds.
• Major reptile orders: Squamata (lizards), Testudines (turtles), Crocodylia (crocodiles).

Dinosaurs and Their Evolution

• Divided into Ornithischia (bird-hipped) and Saurischia (lizard-hipped).
• Birds evolved from theropod dinosaurs.

The Age of Mammals

• Post-KT extinction led to mammal diversification.
• Major mammal categories: monotremes (egg-laying), marsupials, placentals.

Placental Mammals

• Split into Boreoeutheria and Atlantogenata, with diverse orders (e.g., carnivores, primates).

Primates

• Divided into prosimians (e.g., tarsiers) and simians (monkeys and apes).
• Humans closely related to chimpanzees.
• Important genera: Australopithecus and Homo.

Conclusion

• Acceptance of evolution does not contradict belief in God.
• Recommended readings:
  • "Why Evolution is True" by Jerry Coyne.
  • "The Greatest Show on Earth" by Richard Dawkins.
  • "Your Inner Fish" by Neil Shubin.
  • "Finding Darwin's God" by Kenneth Miller.