Transcript Emergence of Evolutionary Thought

Emergence of Evolutionary Thought
Evolution: __________________ in populations of
organisms over time
Early Explanation of life’s diversity
Species individually created ________________ and
__________________
Questions arising from such thoughts
Why were organisms ________________ in different
regions of earth?
Why are ____________organisms different from
________________ organisms?
If each species is different, why are there the same
________________________________ (bone plans)
that do different things in animals?
New Ideas
Scientists thought that species _________ over time
Both animals, though very different,
exhibit similar wing structures
Extinction, fossil record, and Carbon-14 dating
suggest that organisms arose (and became
extinct) at different time periods
Dinosaurs- Arise ~ 200 myaExtinct 65 mya
Chimps- Arose on earth ~6 million years ago
Woolly Mammoth- Extinct
4500 years ago
Different regions of planet have animals
with unique traits that help them survive
New Ideas
Scientists thought that species ___________
over time
Lamarck’s Disproven Theory of Evolution
Jean Baptiste Lamarck
Believed that an animal’s ____________
_____ determine its development and genes
Exp. Giraffe
Early Giraffes stretched their necks to feed
Long neck was then _________ to offspring
____________________
Charles Darwin 1809-1882
Putting the Picture Together
Darwin Travels to the Galapagos Islands
Witnessed ______________________ of animal life
Fascinated by differences among _______________
Becomes convinced that species _______________
Young bull
Old bull
Thomas Malthus & Charles Darwin
Malthus
Populations tend to ______________ than
the food supply needed to feed it
Charles Lyell & Charles Darwin
Lyell
Changes occur over time in geology; land
______________________________________
Darwn’s Descent with Modification
Evolutionary pathway resembled a _____________
_______ a ladder from lower forms to higher forms
No species that exists today was an ____________
to another living species
Darwin’s Observations
•_____________ in a population ___________,
some of these variations are inheritable
•Populations produce __________________ than
the environment’s food, space, and other assets.
•Therefore, species _______________for resources
Lions and cheetahs compete for food
Dolphins compete for baitfish
The Mechanism of Natural Selection
Natural Selection ___________________________ displayed
by individuals with _____________ traits
Nature _____________ traits that are passed on to the next
generation
Variation _________________ within a population
Adaptations traits that are selected for because they help
an __________________________________
Evolution occurs when _________ in a population change
shift to enhance ___________________________
Exp. Giraffe
How Do Variations Arise?
•Natural selection __________ the cause of variation
•Mutation-> Random ______________ in DNA
sequences in the parents genome
•Gene Shuffling ________ of parental
chromosomes can create ____ genetic combinations
•Variation arises _________________. Variations are
then selected on by nature.
•Variations which are selected for are called
_____________________
Adaptations and Speciation
Types of Adaptations
•Structural Adaptations  Involve ___________ or
_________________
Bird’s beak, Anteaters _____________________
•Physiological Adaptations  ___________________
in organisms
Poison ___________in a snake, _____ of an octopus
•Behavioral Adaptations  _______________ aids in
survival and reproduction
Wildabeasts/ Caribou/ Bird ___________________
Wolves ______________ in Packs
Fish swim in ___________________
Types of Adaptations
Structural
Physiological
Wolf Pack
Herd of African Gazelles
Species & Speciation
Species  group of organisms that can
__________________and produce ________offspring
Horses + Donkey = ________…Not the same species
Human male + human female = _______________
baby…same species!
Speciation  Organisms which are separated by
distance + gene pool will ______________
interbreed. Each group becomes ________________
Horse
Donkey
Mule
Types of Natural Selection
Directional Selection  shifts a population toward
____________________ form of a trait
Example: 4 million years ago; heavy cheetahs
Over time, _______________________ animals
reproduced more successfully
Natural selection favored the genes that pushed the
cheetah’s weight in ___________________________
Types of Natural Selection
Stabilizing Selection shifts a population toward
________________________ traits
Example: Most human babies weight ~ ___________
Disruptive Selection  ______________ phenotypes
are more common
Example: African butterflies appear as either bright
_____________________________
These colors mimic other butterflies that are ______
____________________; less likely to be eaten
Intermediate butterflies look like __________, and
are _____________________ to be eaten
Patterns of Evolution
Species become ____________________ over time
Gradual Change  Genetic changes occur
_____________over ______________ generations
Divergent Evolution  Single population is split
into ________________ populations.
Exp. Ground squirrels in the Grand Canyon were
split into _________________ after canyon widened
Patterns of Evolution
Adaptive Radiation  Organisms occupy
________________niches in an environment and
_______________________from one another
Exp. Darwin’s Finches
Convergent Evolution  ________________ species
evolve in ways to make them _________more similar
Exp. Sugar Gliders winged marsupials in ________
Flying Squirrels  Winged squirrels in ___________
_____________________________
Sugar Glider
Flying Squirrel
Populations & Evolution
• Larger populations tend to have ______ genetic variation
• Smaller populations tend to have ________ genetic variation
• Genetic Drift/Founder Effect _____________________due
small population sizes. _______________ more likely
• 10,000 years ago, _____________________go extinct due to
climate changes. Resulting cheetahs have little genetic
diversity
Pace of Evolution
Gradualism  Over time, new species arise as
environment change
If true, we should see ____________________ in
fossil record…not always true
Punctuated Equilibrium  Species exist for long
periods of time without changes, then
________________ occur over short periods of time
Evidence for Evolution
Fossil  ______________ that is preserved in rock
Found in _________________________
Fossils show overall ___________________ of how
living things evolved
Body ___________
Feeding __________
Mobility
Society?
_____________ fossils in upper layers, __________
fossils in lower layers
Examples
Burgess Shale
Location : ___________________________________
Development: Foot of _________________________
Organisms: Early Marine worms ________________
Badlands, SD
Development: ______________________
Organisms: _________________________
Badlands
Importance
Land _____________________
Were once covered _________________________
Species ________________________
Comparative Anatomy
Homologous structures ____________________ in
related organisms
Suggests that organisms ______________________
ancestor
Exp. Cheetah forelimb = _______________________
Wing = ________________________
Vestigial Organs
Organs with no apparent use, but resemble
______________________ in ancestors
Whale ____________
Whale ____________
Wisdom __________
__________________
Comparative Embryology
Organisms with common descent have
_________________
Vertebrates breathe _____________________
As embryos, ________________________ (turns into
Eustachian tube)
Biochemistry
Common ancestors have similar fundamental body
chemistry
Most organisms have:
Same ______________________
Same ______________________
Biogeography
Study of species distribution on Galapagos Islands
____________________________________ species
Each island would have to had it own special
creation event for each species; more likely
____________________________________________
Direct Evidence
Bacteria & _____________________
Fruit Flies (Drosophila)
Artificial Selection
Artificial selection (or selective breeding) describes
intentional breeding for certain traits, or combination of traits
Dogs are a prime example.
Bulldogs selectively bred for increasingly large heads. Most
bulldogs delivered via Caesarian Section. Trait not favored
in nature, but selected for by humans