Download Evolution Guided Notes

Guided Notes: Evolution
The Theory of Evolution



______________ is the change in ____________ traits through generations
______________ over ______________!
Occurs in _________________, NOT individual organisms
How Have Organisms Changed?






At the time life emerged, the Earth was thought to contain very little
_________________
o First cells were thought to be ________________________
o Recall that “anaerobic” means “__________________________________”
As the atmosphere of Earth changed, so did the development of organisms
These ________________ (simple), anaerobic cells were able to exist in Earth’s early
atmosphere
As Earth’s atmosphere and conditions changed, ___________________ prokaryotes
evolved, using sunlight to produce food.
o What molecule do photosynthetic organisms produce as waste? ___________
Eventually, Earth’s atmosphere became filled with ____________________
o ______________organisms evolved
This resulted in the evolution of ___________________ complex ________________
organisms we have on Earth today!
The Endosymbiotic Theory:



The __________________________ proposes that eukaryotic cells arose from living communities
formed by prokaryotic organisms.
~2 billion years ago - ________________ of internal membranes in _________________
o The result was the ancestor of all _____________ cells.
Endosymbiotic Theory: Eukaryotic cells formed from a____________ among several different
prokaryotic organisms
o Prokaryotes that use oxygen to generate energy-rich molecules of ATP evolved into
_______________________
o Prokaryotes that carried out photosynthesis evolved into ________________________
Evidence of Evolution



Fossil Evidence: ___________________ show us the similarities between organisms of the
past and present
__________________ describe similarities between the
anatomical structures of species
__________________ are anatomical structures that still
appear, but are no longer used!
o Examples: _____________________________
______________________________________
o Suggests that these structures may have existed
at a previous time or in an ancestor; organisms
evolved and structures

Comparative Embryology: Insects and animals often have very
similar _________________ development
o Ex. _________________________________________
o Suggests a _________________________

Biochemical Evidence: Comparison of ______________ and macromolecules between
organisms
o Through _____________________________________
o Tells us what organisms are closely related
Evolution and Natural Selection





________________ is best known for his contributions to the theory of Evolution
On a five year voyage on a ship called the Beagle, Darwin recorded his observations of
_______________________________ he found along the way
This led Darwin to develop the idea of __________________ and __________________
_____________________________means that those organisms best adapted to their
environment will survive, reproduce, and ______________________
o “Fittest” means _____________________, not strongest!
Adaptation: Any _______________ trait an organism has that helps it to ________________
o If an organism does not have adaptations to best fit its environment, it will die
o “Survival of the Fittest”
o Example: Bird beaks-Imagine that birds had different sized beaks in an area where the
food source was seeds. In order to crack them, the birds needed a large, strong beak.
Which would survive and reproduce?

Species have the potential to increase _____________________, but environmental factors
maintain lower population numbers
o Resources required to sustain _____________
o ___________________ conditions
o Relationships among organisms in ________________

Changing environments select for specific ____________________
o Those organisms with favorable _______________________ survive, reproduce, and
pass on their _____________ to future generation
o Over time, the accumulation of favored alleles leads to a change in ________________
(change over time = evolution)
Case Study: Antibiotic Resistance




Organisms are constantly changing and adapting; __________________ reproduce and
evolve quickly to adapt to constant changes!
Humans often use ____________________ to combat harmful bacteria (ex. Staphylococcus)
Some bacteria are born with a ______________ resistance (an adaptation!) to the antibiotic
These bacteria will ________________ and ________________, creating a group that are
resistant to the drugs
Other Disease Agents in Natural Selection


__________________ Resistance in Plants
Antivirals

Passive Immunity: Immunity to certain diseases is given from ________________ to
____________ at birth
o Continued through antibodies passed through ___________________

Active Immunity: Immunity acquired through exposure to a ______________
o After exposure, your body builds up an ________________
o _________________ allow you to artificially gain an active immunity without exposure
to the actual disease
Causes of Variation

Genetic Recombination: Dominant and Recessive alleles in genes, along with polygenetic
traits and complex genetics, lead to individual organisms with different ________________
(and thus, adaptations)

Mutations: Changes in DNA sequences can introduce both good and bad new ___________
into a population (ex. Immunities, resistant bacteria, pesticide resistant plants)
Speciation

____________________ refers to the ____________________ process by which new species
arise

Directional Selection
o When ____________________ phenotype has the best
chance to survive
o As a result, the______________ (number) of those with
that phenotype shift over time
o Example: The evolution of horses
Using the diagram as evidence, how did the horse evolve over
time? Hypothesize why these changes could have happened.

Stabilizing Selection
o When the ____________________ phenotype has the
best chance to survive
o _______________________ advantage
o Example: Birth weight

Disruptive Selection
o When _______________________ phenotypes have the
best chance to survive
o Example: Peppered moth
Geographic Isolation



When mountains, islands, etc. keep a population __________________
Species will meet different environmental challenges, change and evolve
____________________than the ____________________ population
Geographic Isolation leads to ______________________________, when one species
evolves into many different species over time due to competition of habitat or food!
Variation

Differences in ________________ within one ________________
o Example: _____________________________________
o Brown eyes are naturally protected from the sun’s glare
Coevolution

When one _______________ evolves due to a specific interaction with __________________
o Example: ______________________________________________________________
Genetic Drift

The change in a___________________ of a gene variant (allele) in a population due to
random _______________________
o Due to a random event, a ____________________________ happens to the organisms
in a population
o Much more frequent in _______________ populations!
o Example:
 Founder Effect
 Bottleneck Effect
Classification Systems





Classification systems are how we __________________organisms
o This is called _____________________
The classification of organisms has changed and evolved over the years due to new
____________________
Greater understanding of evolutionary relationships, thanks to ________________________,
has allowed for more detailed classification
The classification of organisms begins with the______________ groupings and moves down
to the _________________ (domain species)
The classification order is as follows:
_________ _________  _________  _________  _________  _________  _________

Species: Group of the _________________ organisms
o Live together
o Mate and produce viable _________________
o “______________” means they can have babies of their own

Scientific Name: The scientific name of an organism is the____________ and
_____________ of an organism
o Always written in ______________
o Example: Humans are Homo Sapians
o Only species are able to ________________!

Case Study: Interbreeding
o Only species are able to interbreed. Organisms of two different species normally will not
_______________________
o Sometimes, organisms within the same genus are able to ________________, but the
offspring are not _________________ (they cannot reproduce!)
o Example: _____________________________________
o These hybrid organisms are much more common in captivity than in the wild
Dichotomous Keys



A key that helps ________________ an organism
Uses ___________________ to lead you to the ___________________ of an organism
By looking at features of an organism, the key will help you determine what it is!
Phylogenetic Trees


Shows the ______________________________ between organisms
Can show which organisms are more closely _______________ than other organisms
Which organism is more closely
related to man? __________
Which organism is man more closely
related to: Frog or bird? Why?
 Cladogram: Shows relationships up-close;
___________________they share