Name: ___________________________________________
Date: _________________________
Forces of Change Notes
Evolution (review):
 The process of change in a species over a long period of time
 Organisms with the traits that help them survive best in their environment, will survive longer and pass
on their genes to more offspring.
 This will cause these traits or adaptations to be found in higher frequencies in future populations.
Forces of Change:
 Overproduction
 Finite Resouces
 Natural Selection
 Genetic Variation
Overproduction:
 Every generation produces more offspring than can possibly
survive.
 If all of these organisms survived they would overrun the
Earth.
 These organisms compete for the finite resources to
determine which organisms survive and which die.
Finite Resources:
 Overproduction lead to competition for resources.
 Most resources, such as food, water, shelter, mates, and sunlight, will run out.
 These are finite resources because there is not enough to support every organism born.
Natural Selection:
 The organisms with adaptations that help them outcompete other organisms for the finite resources
are the ones who will survive to pass on their genes.
 These organisms typically have traits that help them evade predators, deal with harsh conditions of the
environment, and find or hunt food.
Genetic Variation:
 New traits usually start from normal variations that already exist within a population.
 Some of these variations give an organism an advantage .
 For example, the whiter a arctic hare is, the more it will blend in with its surrounding to hide from
predators. This is a high adaptive value.
 Genetic variation is cause by:
 Sexual reproduction
 Crossing over during meiosis
 Mutations
 Changes in genes can lead to:
 Structural changes (ex: skin color, limb structure, etc)
 Functional Changes (ex: eels using the electrical output created by muscles to electrocute prey)
 Behavioral Changes (ex: blinking of fireflies that allows them to communicate)
Biodiversity:
 Variation in a population is important because the environment changes.
 If all organisms of a species were exactly the same, a small environmental change could wipe out an
entire species.
 Once diversity is lost it is nearly impossible to get back.
 That is why scientists try to protect endangered species.
Patterns of Change:
 Changes in a species is often related to environmental changes
› So, a rapidly changing environment will lead evolution to occur more rapidly.
 Species with short reproductive cycles producing more offspring tend to evolve more quickly.
 Failure to adapt to a change in the environment may lead to extinction.
Extinction:
 The disappearance of an entire species.
 Extinction is possible when the death rate is
higher than the birth rate.
 Extinction is usually caused by big
environmental changes
 Sometimes these big environmental changes
are the fault of humans.
Phylogenetic Trees:
 Phylogenetic trees show us when a species
divided to become two separate species.
 We can also see which species were poorly
adapted and became extinct.
 We can determine which organisms are most
closely related, by looking at which organisms
have the most recent common ancestor.
Name: ___________________________________________
Date: _________________________
Forces of Change Notes
Evolution (review):
 The process of change in a ____________ over a ____________ period of time
 Organisms with the traits that help them ________________ best in their environment, will survive
longer and pass on their _____________ to more __________________
 This will cause these traits or __________________ to be found in _______________ frequencies in
future populations.
Forces of Change:
 Overproduction
 Finite Resouces
 Natural Selection
 Genetic Variation
Overproduction:
 Every generation produces ____________ offspring than can possibly ________________
 If all of these organisms survived they would overrun the Earth.
 These organisms ________________ for the finite ________________ to determine which organisms
_______________ and which die.
Finite Resources:
 Overproduction lead to competition for resources.
 Most resources, such as ___________, water, shelter, ____________, and sunlight, will run out.
 These are _______________ resources because there is ________ enough to _______________ every
organism born.
Natural Selection:
 The organisms with _______________________ that help them ___________________ other
organisms for the finite resources are the ones who will survive to pass on their genes.
 These organisms typically have traits that help them _____________ predators, deal with harsh
conditions of the __________________, and find or hunt ______________
Genetic Variation:
 ___________ traits usually start from __________________ variations that already exist within a
population.
 Some of these variations give an organism an __________________
 For example, the whiter an arctic hare is, the more it will ____________ in with its surrounding to hide
from predators. This is a __________ adaptive ___________
 Genetic variation is cause by:
 ______________ reproduction
 Crossing over during ______________
 ____________________
 Changes in genes can lead to:
 Structural changes (ex: skin color, limb structure, etc)
 Functional Changes (ex: eels using the electrical output created by muscles to electrocute prey)
 Behavioral Changes (ex: blinking of fireflies that allows them to communicate)
Biodiversity:
 Variation in a population is important because the environment _______________
 If all organisms of a species were exactly the ____________, a small environmental change could wipe
out an _____________ species.
 Once diversity is ____________ it is nearly __________________ to get back.
 That is why scientists try to protect ______________________ species.
Patterns of Change:
 Changes in a _______________ is often related to ____________________ changes
›
So, a rapidly _______________ environment will lead _________________ to occur more
__________________
 Species with short ___________________ cycles producing ____________ offspring tend to evolve
more __________________
 _______________ to adapt to a change in the environment may lead to ___________________
Extinction:
 The _________________________ of an entire species.
 Extinction is possible when the _______________ rate is ____________________ than the
__________ rate.
 Extinction is usually caused by __________ environmental changes
 Sometimes these big environmental changes are the fault of __________________
Phylogenetic Trees:
 Phylogenetic trees show us when a species
________________ to become two separate
species.
 We can also see which species were
_________________ adapted and became
_________________
 We can determine which organisms are
most closely _________________, by
looking at which organisms have the most
___________________ common ancestor.
Classification Notes
1: What everyday things do we categorize into groups?
2: How do we determine these groups?
Classification - ________________________________________________________________
 Must be ___________________ and ________________ to understand.
 Must be ___________________ (the same) at different times in different
____________.
Taxonomy - __________________________________________________________________
_____________________________________________________________________________
History of Classification:
Aristotle
 Created two kingdoms: ______________ and ______________________
 Grouped animals based on where they ________________: creatures of the
__________, _______________, and _________________.
 Too many animals did not fit into those categories. (Ex:_____________________)
Linnaeus
 Created a system of classifying animals based on their ______________________
 These similarities included _____________ structure, body __________________,
shape, color, and means of obtaining ________________.
Modern Classification
 Looks at the traits ___________________ used (ex: size and body ___________) and
also traits that are not so easy to observe (ex: ____________________ in the body and
____________)
 Our modern classification system has ________________ levels.
K_________________
Phylum
King
P________________
C______________
Came
Order
O_______________
F______________
Genus
S________________
For
G_____________
Spaghetti
Phylogeny:
 Since ________________ came up with the theory of common descent, we have been
trying to make ___________________________ between species and figure out how
the ____________________ of life progressed
 We use _________________ to show these connections
 Any _________________ point on a tree indicates when a common
_________________ changed to become ___________ or more separate
_______________
 The organisms that share a more _________________ common ancestor are more
closely ________________
Phylogenetic Trees:
 Uses __________ or __________ questions to create groups.
 Gives a visual of the ____________________.
Dichotomous Key:
 An ______________________ way for other scientists to find out which group(s) and
new ____________________ might belong to.
 Puts the ____________ into chart form.
Questions:
1: What is a Dichotomous (Die-cot-o-mus) Key used for?
2: Who was the first to start to categorize animals?
3: What are Phylogenetic trees and what do they show us?
4: What does it mean for something to go extinct?
5: What does finite resource mean?
6: What is Biodiversity and why is it important?
7: Why is Genetic Variation important for survival?
8: What is Natural Selection?
9: What is Evolution and what causes it to happen?