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• PHYLOGENETIC TREE

  A phylogenetic tree, also known

  as a phylogeny, is a diagram that

  depicts the lines of evolutionary

  descent of different species,

  organisms, or genes from a

  common ancestor.
• The Earth is 4.6

  billion years old!
• The geologic time scale is the

  “calendar” for events in Earth

  history.

  ● The geologic time scale divides

  up the history of the earth based

  on life-forms that have existed

  during specific times since the

  creation of the planet
• Eons are the largest intervals of

  geologic time and and are

  hundreds of millions of years of

  duration.

  • Earth’s

  history

  has

  been

  divided into four eons: Hadean,

  Archean,

  Proterozoic,

  Phanerozoic.
• Hadean is the oldest eon and was

  officially recognized only in 2012.

  • Its name was derived from the

  word

  Hades

  (god

  of

  the

  underworld in Greek mythology),

  referring to the hellish conditions

  and violent cosmic collisions that

  characterized Earth four billion

  years ago
• Archean eon is still not much clear

  among geologists due to the few

  fossil or mineral evidence that

  could support it.
• Proterozoic eon is characterized

  by the presence of oxygen in the

  atmosphere

  due

  to

  the

  emergence

  of

  cyanobacteria,

  allowing other organisms, such as

  eukaryotes and other multicellular

  organisms to live
• Phanerozoic eon spans within the

  past 541 million years up to

  present.

  • The eon is linked with the

  Cambrian explosion, which is rapid

  evolutionary event when complex

  organisms believed to have first

  evolved on Earth appeared.
• Phanerozoic eon spans within the

  past 541 million years up to

  present.

  • The eon is linked with the

  Cambrian explosion, which is rapid

  evolutionary event when complex

  organisms believed to have first

  evolved on Earth appeared.
• Era is the division in an era that span

  time periods of tens to

  hundred of million years.
• Period is a division of geologic history

  that spans no more than one

  hundred million years.
• Epoch is the smallest division of the

  geologic

  time

  scale

  characterized by distinctive

  organism
• The Paleozoic (paleo means

  “ancient”

  or

  “early”,

  zoic

  means “life”) era lasted for 300

  million years.

  Age of invertibrates
• The Mesozoic (meso means

  “middle”) era lasted 180 million

  years.

  • Age of Dinosaurs
• The Cenozoic (ceno means

  “latest”) era began 65 million

  years ago until present.

  Age of Mammals
• Cambrian

  • Explosion of life

  • All existing phyla come into being

  at this time

  • Life forms in warm seas as oxygen

  levels rise enough to support life

  • Dominant

  animals:

  Marine

  invertebrates

  (trilobites

  and

  brachiopods)

  • Supercontinent Gondwana forms

  near the South Pole (note position

  of present-day Florida)
• Ordovician

  • The 1st animals with bones

  appear, though dominant animals

  are still trilobites, brachiopods and

  corals.

  • A very cold time in Earth’s history:

  there was a great extinction due

  to ice caps in present-day Africa

  • Four main continents: Gondwana,

  Baltica, Siberia and Laurentia
• Silurian

  • First land plants appear and

  land animals follow

  • Laurentia collides with Baltica

  and closes Iapetus Sea.

  • Coral reefs expand and land

  plants

  begin

  to

  colonize

  barren land.

  • First millipede fossils and sea

  scorpions (Euryptides) found

  in this period.
• Devonian

  • Forests spread across the

  land

  • The Golden Age of Fish

  • Tetrapods colonise the

  land

  • Development of reefs

  • First insects learn to fly

  • Mass extinction event
• Carboniferous

  • Diversification of insects and

  arachnids

  • Highest ever oxygen levels

  • Extensive formation of coal

  beds

  • Decline of trilobites

  • Evolution of the first reptiles

  • Climate change leads to

  rainforest collapse
• Permian

  • Great climate variation

  • Ancestors of mammals

  evolve

  • Rise of dimetrodons

  • Formation of Pangaea

  • Worst extinction event in

  Earth’s history

  • Major drop in sea levels
• Triassic

  • First dinosaurs appear

  • First

  mammalssmall

  rodents appear

  • Life and fauna re-diversify

  • Rocky Mountains form.

  • First turtle fossil from this

  period

  • Pangea breaks apart
• Jurassic

  • Largest dinosaurs evolve

  • Major maritime radiation

  • First ceratopsians evolve

  • Pangaea supercontinent splits

  up

  • Stegosaurus evolves

  • Missing link between dinosaurs

  and birds appears
• Cretaceous

  • Atlantic Ocean forms

  • Mammals feed on dinosaurs

  • Flowering plants and grasses

  appear

  • Australia and Antarctica split

  apart

  • Tyrannosaurus rex evolves

  • Impact

  event

  devastates

  Earth
• Tertiary

  • First

  horses

  appear

  and

  tropical

  plants

  dominate (Paleocene)

  •Grasses spread and whales, rhinos, elephants and

  other large mammals develop. Sea level rises and

  limestone deposits form in S.C. (Eocene)

  •Dogs, cats, and apes appear (Oligocene)
• Tertiary

  • Horses, mastadons, camels,

  and tigers roam free in S.C.

  (Miocene)

  • Hominids develop and the

  Grand

  Canyon

  forms

  (Pliocene)
• Quaternary

  • Modern humans develop

  and

  ice

  sheets

  are

  predominantIce

  age

  (Pleistocene)

  • Holocene Humans flourish

  (Holocene)