Download EVOLUTION NOTES PACKET

EVOLUTION NOTES PACKET
Theory:
 Definition: ________________________________________________________

__________________________________________________________________
o Observations lead to hypotheses, hypotheses lead to experiments, many
experiments lead to a theory.
o Can be modified, or even proven false
o Considered successful if it can be used to make measurable, testable
predictions that are correct
EX: Cell Theory
Law:
 Definition: ________________________________________________________
__________________________________________________________________
o Observations lead to a mathematical model, model is used to describe
events, measurements of events are used to reinforce model
o Always the same outcomes under the same conditions
o Can be modified, or even proven false

EX: Newton’s Laws of Motion, Law of Gravity
Biology deals with theories, not laws. Physics and Chemistry deal more with laws
then theories.
The Theory of Evolution:

A collection of facts, observations, hypotheses and explanations about how
__________________________________________________________________
__________________________________________________________________

Evolution: ________________________________________________________
Introduction and Terminology
Variation and Species:
 A species is an _______________________ population of organisms that can
reproduce __________________, _________________________ offspring

Variation is the ____________________________________________________
__________________________________________________________________
o EX: hair color; fur color; height; size

Variations can be physical, behavioral, or chemical
o EX:
 Physical - color, size
 Behavioral - mating rituals, diet
 Chemical - blood type, hormone levels

Variation creates a population w/ ____________________________________
and these traits determine the _________________________________________
in an environment.

________________________ and _____________________________________
(during crossing over of meiosis) cause variations with in populations
o Mutations can be positive, negative, or have no effect for an organism
 Positive mutations help the organism to survive allowing them to
__________________________ and pass that positive mutation on
to their offspring
Adaptations:
 ___________________________________ are inherited traits that increase an
organism’s (or population’s) chances of survival in an environment

There are many types of adaptations that help organisms to survive better

Adaptations allow populations to become suited to a specific niche
o Niche is a _________________________________________________
___________________________________________. A niche includes:
 Habitat, diet, raising offspring, and predation
Jean Baptiste LaMarck

A French naturalist that did his work prior to Charles Darwin and Alfred R.
Wallace

Suggested evolution as a ________________________________________ to
explain relationships of fossils to current organisms
o Among the first scientist to recognize that living things changed over time

LaMarck’s Theory of Acquired Characters had 3 main ideas:
1. Desire to Change: __________________________________________________
a. EX: Giraffes – according to LaMarck, giraffes have long necks because
they stretched their necks to reach the leaves that were higher on trees
2. Use and disuse: most used body structures ____________________________ and
the unused structures ____________________________________
a. EX: Giraffes – used their necks for reaching leaves, so their necks
continued to develop and get longer
3. Passing on of ______________________________ traits
a. EX: Giraffes – giraffes that stretched their necks passed on their stretched
neck
IMPORTANT: LaMarck was incorrect, but he is still credited with being one of the
first people to devise a theory of evolution and adaptation!
Charles Darwin

A little history
o Boat he traveled on: ____________________________________
o Islands he spent a lot of time on: ___________________________
o Animals he focused on: __________________________________
o Book he wrote: _____________________________________
Natural Selection

Natural Selection: ___________________________________________________
____________________________________________________________________
o Some part of the organism's environment selects the traits
o Organisms with traits beneficial in the environment survive, reproduce and
pass those traits on to their offspring
 Which would be more likely to survive in a muddy pond, a bright
red frog or a brown frog? Why?
Main Points of Natural Selection
1. Living things ______________________________________________
 More offspring are produced than survive
o EX: frogs produce hundreds of eggs, but only a few develop into adult
frogs
2. There is _____________________________________ in traits among individuals
 Each living thing does not appear exactly like all the others
3. There is a struggle to __________________________, _____________ for resources
 There are more living things than there are resources
 Organisms compete with each other for resources and survival
4. _______________________________________________ is always taking place
o Individuals with traits that increase fitness have more offspring than those
without those traits
 Fitness: ______________________________________________
_____________________________________________________

Individuals that survive and reproduce will pass their traits to their offspring, so
the traits of better adapted individuals will increase in proportion in the population
over time.
***Remember: New traits arise from mutations, or changes in DNA***
The Development of New Species
Species
 Species: __________________________________________________________
_________________________________________________________________
Speciation

Speciation: ________________________________________________________
o Speciation commonly occurs when members of a species have been
separated
Separation of Species

New species may form due to:
o _______________________________________________ (rivers, oceans,
mountains, glaciers, lava flows)

Animals of the same species find themselves living in different
environments

This causes ________________________________________, or
the separation of population so that species cannot interbreed

Natural Selection will work separately on each group


With different gene pools, different adaptations can appear
in each group

This increases the differences between the groups and their
gene pools become more dissimilar, eventually creating 2
different species
EX: species of finches on Galapagos Islands

Each species of finch had a different beak shape to suit the
food on their island
Evidence of Evolution
Fossils
 Fossils are _________________________________________________________

Fossils are found in ___________________________________ rocks
o Position of fossils in rock layers reveal the relative age of the organism

Fossil record: ______________________________________________________
__________________________________________________________________
o Some fossils are not preserved well and some organisms do not leave
fossils at all - this accounts for gaps in the fossil record
o The fossil record provides information about:
 The _____________ of the Earth

___________________ in Earth

Evolution of _______________________

Earth’s _____________________ and ______________________
Homologous Structures (aka comparative anatomy)

Homologous Structures are traits that have _______________________ structures
but _______________________________ functions in different species
o EX: Flippers, hands, bat wings, and bird wings all function differently, yet
are made up of the same group of bones!

Certain anatomical similarities among species support evolutionary history
Vestigial Structures

Vestigial Structures are structures that are _____________________________
and often ___________________________
o Historical remnants of structures important in ancestors

EX: whales of today lack hindlimbs, yet have vestiges of the pelvis
and leg bones of their 4-footed terrestrial ancestors
Comparative Embryology

Comparison of structures that appear during the development of different
organisms

Closely related organisms often have similar stages in embryonic development

Evidence that vertebrates evolved from a ________________________________
o All vertebrates (fishes, frogs, snakes, birds, apes) have gill pouches/slits
on sides of throat during embryonic stage
Comparative Biochemistry (molecular biology)

Common genetic code shared by all species

Evolutionary relationships among species leave signs in DNA/proteins
(genes/gene products)

If 2 species have genes/proteins with sequences that match closely, sequences
must have been copied from __________________________________________

EX:
o _______________________________________is a protein used in
respiration by all organisms
o _____________________ is an energy molecule for all living things
o All organisms use _________ and __________ to transmit genetic info
Biogeography

Biogeography is the study of __________________________________________
__________________________________________________________________
o Suggested to Darwin that organisms evolved from ancestral forms


Galapagos animals resembled species of South American mainland
more than animals on similar but distant islands
EX:
o Tropical animals of South America more closely related to species in
South American deserts than to species in African tropics