Download Slide 1

• How many species that once lived on
Earth do you think are still present today?
Give a %
• p. 422 #1, 2, p. 440 #2, 5
• (lab) Comparing Bird Adaptations
• 4.6 Billion Years Old
• 4 BYA- early life originates
• 3.2 BYA- oxygen released into atm.
• 2.1 BYA- first eukaryotes
• 530 MYA- first life on land
• 246-144 MYA- dinosaurs
• 150-160 KYA- earliest Homo
sapiens on Earth
• Early Earth’s atmosphere
• NO ORGANIC COMPOUNDS
• contained building blocks (Carbon,
hydrogen in various compounds
• Organics require lots of energy to form
• Thought to have formed as result
of lightning
• bubbles made holding organic cpds.
• Index Fossils
• Fossils used to be compared to
other unknown fossils
• Can see relative age
• if above, = younger
• Carbon Dating
• Method of using radioactive carbon
to give date fossil was formed
• Can use these two to give dates that
different species existed on Earth
• By looking at fossil records, can see
5 major extinctions in Earth’s history
• last one 65 MYA- dinosaurs along
with MANY others
• The 6th extinction?
• Currently, species disappearing at
rates unparalleled in Earth’s history
• Caused by humans?
• Primordial soup
• Molecules present on early Earth
• Combined with energy added, can
make organic compounds
• made simple bacteria
• lipid surrounding DNA
• From bacterial life to multicellular life…
• **Endosymbiotic theory
• one bacteria ingested another,
and developed the ability to work
with that structure
• over time, different bacteria with
different functions were taken in,
resulting in the modern eukaryote
• evidence: mitochondria with their
own DNA!!!
• Punctuated Equillibrium
• Adaptive Radiation
• Coevolution
• Convergent Evolution
• Theory to explain that long periods of
equillibrium exist, followed by short,
rapid phases of evolution
• Generally follow mass extinctions
in Earth’s history
• **WHY?
• When two species evolve in
response to each other
• *Think of snake and newt as example• one develops greater toxicity to
protect itself, while other evolves
higher resistance to toxicity
• When one species evolves into a
number of different species
• Think about Darwin’s finches• began as one species, but evolved
into 14 different species depending
on the niche being filled
• When two species evolve similar,
but distinctly different structures
•Ex- bat wing and fly wing
• How is the “6th extinction” different from the 5
prior extinctions in Earth’s history?
• p. 422 #1, 2, p. 440 #2, 5
• (lab) Comparing Bird Adaptations