Download PPT NOTES_AP Biology Chapter 25 Notes

AP Biology Chapter 25 Notes
The History of Life on Earth
What you need to know…
• The ____________ of the Earth and when prokaryotic and eukaryotic life emerged.
• Characteristics of the _____________ planet and its atmosphere.
• How ___________ and _______________ tested the Oparin-Haldane hypothesis and what they learned.
• Methods used to __________________ fossils and rocks.
• Evidence for _____________________________.
• How continental drift can explain the current ___________________ of species.
Concept 25.1: Conditions on early Earth made the origin of life possible
 Chemical and physical processes on early Earth may have produced very simple cells through a
sequence of 4 stages:
1. Small ________________________ molecules were synthesized
2. Joining of these small molecules into ___________________________ (proteins, carbs, etc)
3. Packaging of molecules into “________________________” (membrane-containing droplets, whose
internal chemistry differed from that of the external environment)
4. Origin of ______________-replicating molecules
 A. I. Oparin and J. B. S. Haldane – hypothesized that the ____________ atmosphere, thick with water
vapor, nitrogen, carbon dioxide, methane, ammonia, hydrogen, and hydrogen sulfide, with energy from
lightening and UV radiation could have formed organic compounds
 Stanley Miller and Harold Urey conducted lab experiments to test this __________________________
and produced a variety of amino acids
 ________________________________ are aggregates of abiotically produced molecules surrounded by
a membrane or membrane-like structure
 The first genetic material was probably self-replicating RNA, not DNA
o RNA molecules called ________________ have been found to catalyze many different reactions
o For example, ribozymes can make complementary copies of short stretches of their own
sequence or other short pieces of _________________
Concept 25.2: The fossil record documents the history of life
• The fossil record is biased in favor of species that
– ___________________ for a long time
– Were __________________________ and _____________________________
– Had ______________________ parts
• The absolute ages of fossils can be determined by ______________________ dating
• Each isotope has a known ________________________, the time required for half the parent isotope to
decay
Concept 25.3: Key events in life’s history include the origins of single-celled and multicelled organisms
and the colonization of land
• The _______________________ record is divided into the Archaean, the Proterozoic, and the
Phanerozoic eons
• The oldest known fossils are _________________________, rock-like structures composed of many
layers of bacteria and sediment
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This “oxygen revolution” from 2.7 to 2.2 billion years ago
– Posed a ______________________ for life
– Provided opportunity to ___________________ energy from light
– Allowed organisms to exploit ____________ ecosystems
The hypothesis of ___________________________ proposes that mitochondria and plastids
(chloroplasts and related organelles) were formerly small prokaryotes living within larger host cells
– An __________________________ is a cell that lives within a host cell
– Key evidence supporting an endosymbiotic origin of mitochondria and plastids:
• Similarities in inner ________________________ structures and functions
• ________________________ is similar in these organelles and some prokaryotes
• These organelles __________________ and ______________________ their own DNA
• Their ______________________ are more similar to prokaryotic than eukaryotic
ribosomes
___________________________________________________ began to colonize land about 500
million years ago
______________________________________ likely colonized land together by 420 million years ago
_______________________________________ are the most widespread and diverse land animals
___________________________ evolved from lobe-finned fishes around 365 million years ago
Concept 25.4: The rise and fall of dominant groups reflect continental drift, mass extinctions, and
adaptive radiations
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Earth’s continents move slowly over the underlying hot mantle through the process of
____________________________________________
– Oceanic and continental plates can collide, separate, or slide past each other
– Interactions between plates cause the formation of mountains and islands, and earthquakes
Formation of the supercontinent _____________________ about 250 million years ago had many
effects
– A _______________ in shallow water habitat
– A _________________ and ______________ climate inland
– Changes in ____________________ as continents moved toward and away from the poles
– Changes in _______________ circulation patterns leading to global cooling
The break-up of Pangaea lead to ______________________ speciation
The current distribution of _______________ reflects the movement of continental drift
At times, the rate of ____________________ has increased dramatically and caused a
___________________________________ (loss of large numbers of species in short periods of time)
– By removing large numbers of species, ecological communities can be drastically altered losing
evolutionary ______________________ forever
Mass extinction can pave the way for _______________________________________ (periods of
evolutionary change where groups of organisms form many new species whose adaptations allow them
to fill different ecological niches)
– EX. Galapagoas finch species
Concept 25.5: Major changes in body form can result from changes in the sequences and regulation of
developmental genes
 “_____________” – a filed of study in which evolutionary biology and developmental biology converge
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Illuminating how slight _____________ divergences can be magnified into major
morphological differences between species
 Sometimes, structures that originally played one role gradually acquire a different one –
___________________
 EX. Feathers of modern birds were co-opted for flight after functioning in some other
capacity such as thermoregulation
 _______________________ is an evolutionary change in the rate or timing of developmental events
 The contrasting shapes of human and chimpanzee skulls are the result of small changes in
relative growth rates
 In ______________________________, the rate of reproductive development accelerates compared
with somatic development
 _________________________ genes determine such basic features as where wings and legs will
develop on a bird or how a flower’s parts are arranged
 Ex. Hox Genes
 Hox genes are a class of homeotic genes that provide ____________________ information
during development
 If Hox genes are expressed in the wrong location, body parts can be produced in the wrong
location
You should now be able to…
1. Define radiometric ____________________, serial ______________________, Pangaea, snowball
Earth, __________________, _______________________, and _________________________
2. Describe the contributions made by Oparin, Haldane, Miller, and Urey toward understanding the
________________ of organic molecules
3. Explain why RNA, not DNA, was likely the _____________________ genetic material
4. Describe and suggest evidence for the ____________________ events in the history of life on Earth
from Earth’s origin to 2 billion years ago
5. Briefly describe the Cambrian explosion
6. Explain how continental drift _____________ to Australia’s unique flora and fauna
7. Describe the ___________________ extinctions that ended the Permian and Cretaceous periods
8. Explain the function of ______________ genes