1

Name: _______________________________________________ Date: ________________________ Block: _________

Guided Notes Unit 8: Evolution

With your table partner, jot down answers to the following questions. (This is a GUESS!)

1. How old is the universe? ___________________________

2. How old is the Earth? ___________________________

3. How long has there been life on the Earth? ___________________________

4. How old is the human species (Homo sapiens)? ___________________________

As we discuss in class, right down the CORRECT answers.

1. How old is the universe? ___________________________

2. How old is the Earth? ___________________________

3. How long has there been life on the Earth? ___________________________

4. How old is the human species (Homo sapiens)? ___________________________

Chapter 10: Principles of Evolution

I. Concept 10.1: Early Ideas About Evolution

a. Evolution: _____________________________________________________________________________

b. Beliefs Before Darwin:

i. Species are fixed. (They do not change over time.)

ii. Earth is less than 10,000 years old.

c. How did these ideas change?

i. _______________________________________: studied fossils and hypothesized that the Earth

is much older than a few thousand years old; specific fossils and living animals have certain traits

that are similar, but not exact

ii. _______________________________________: proposed that life evolves or changes; species

are not permanent

2

iii. _______________________________________: proposed that gradual and observable geologic

processes such as erosion could explain the physical features of today’s Earth

iv. _______________________________________: collected specimens & observed the Galapagos

Islands developing two main points

1. Descent with modification: __________________________________________________

________________________________________________________________________

2. Natural selection: _________________________________________________________

________________________________________________________________________

II. Concept 10.2: Darwin’s Observations

a. In 1831, the ship HMA Beagle set sail from England on a 5-

year journey to South America and the Pacific Islands.

Darwin spent most of this trip ashore, observing the land

and its inhabitants.

b. Variation: ________________________________________________________________________

c. Galápagos tortoises that live in areas with tall plants have long necks and legs.

d. Adaptation: a feature that allows __________________________________________________________;

adaptations can lead to __________________________________________________________________

e. What types of observations did Darwin make?

i. Darwin found fossils of extinct animals that resemble modern animals.

ii. Darwin found fossil shells high up in the Andes Mountains.

III. Concept 10.3: Theory of Natural Selection

a. Key Insights for Darwin's Theory of Natural Selection

i. Darwin noticed a lot of variation in domesticated plants and animals.

ii. Artificial selection: ________________________________________________________________

3

1. Examples of Artificial Selection

a. There likely was just a single dog species

500 years ago. Humans have been able to

produce dogs that range widely in different

qualities over a short period of time.

b. Some plants (like corn) show another

example of artificial selection - as

farmers will select the corn with the

"best" traits to continue

reproduction.

b. Natural Selection is: "______________________________________"; a mechanism by which individuals

that have inherited beneficial adaptations produce more offspring on average than do other individuals

c. Biological fitness _______________________________________________________________________

_____________________________________________________________________________________

d. Basically, the more offspring an organism produces during its lifetime, the greater its biological fitness.

e. Example: animal species colonizes a chain of distant and isolated islands (each group of individuals on

each island = a population)

i. Populations learn to adapt to their environments, and over time, the isolated populations become

more different

f. ___________________________________________

___________________________________________

___________________________________________

___________________________________________

g. Natural selection explains how evolution can occur.

h. ___________________________________________

is the mechanism of evolution.

i. Darwin reasoned that natural selection could eventually cause two isolated populations of the same

species to become separate species as they adapted to their different environments.

j. The 4 Basics of Natural Selection

i. _____________________: Individuals in a population show a variety of genes (black fur vs. brown

fur, etc.). And these variations can be passed on from parent to offspring.

4

ii. _______________________________: Some variations allow organisms to be better-suited for

their environment.

iii. _______________________________: Organisms produce more offspring than the environment

can support (you can assume some will die).

iv. _____________________________________________________: These variations that increase

reproductive success will have a better chance of being passed down to the next generation.

k. Darwin’s Theory of natural selection explains how evolution works. He published a book: “On the Origin of

Species by Means of Natural Selection.”

l. Evolution is a remodeling process.

i. In some cases, a complex structure may have evolved from a simpler structure having the same

basic function—a process of refinement.

ii. Chitin: exoskeleton of arthropods originally served as protection for sea creatures from predators -

now serves additional function for land-dwelling descendants, protecting them from dehydration

iii. Growth of the feet of tree-dwelling salamanders ends

earlier in development than those of ground or water-

dwelling salamanders, an adaptation made due to

lifestyle needs of each

5

IV. Concept 10.4: Evidence for Evolution

a. The Fossil Record

i. Fossils: ________________________________________________________________________

______________________________________________________________________________

ii. Most found in sedimentary rock

iii. Fossils show that ancient species share similarities with modern species

iv. Fossil Record: chronological collection of life’s remains in the rock layer (older is usually on the

bottom, newer on top)

v. Derived Traits (newer): _______________________________________________________ (such

as feathers) - They do not appear in the fossils of common ancestors.

vi. Ancestral Traits (older): ______________________________________________________ (teeth,

tails, etc) that appear in older fossils

vii. Example of Evolution:

1. Feathers could have began as “insulation”, eventually becoming useful for flight!?

2. First feathers are believed to be from a non-bird like dinosaur 125 million years ago.

6

b. Geographic Distribution

i. Biogeography: __________________________________________________________________

______________________________________________________________________________

ii. Similar species of organisms (adapted to similar environments) that are geographically closer

share more common characteristics

iii. Patterns of migration explained the relationships

1. (Example: Island species most closely resemble nearest mainland species; Populations

can show variation from one island to another)

2. For example, the mara (left) of South America occupies the same niche (environment, diet,

etc.) as the rabbit in Europe, but they are surprisingly not THAT closely related (evolved

separately)

.

c. Comparative Embryology

i. Embryo: pre-birth stage of an organism’s development (“in the womb”)

ii. ______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

iii. Example: Vertebrate embryos have pharyngeal silts which develop into:

1. In fish = gills

2. In reptiles, birds, & mammals = ears, jaw, and/or the throat

7

d. Comparative Anatomy

i. The relationship between the structure of ancient species and modern species

ii. Think: Comparative = Compare; Anatomy = Body Parts (Structure & Function)

iii. Three Types:

1. _________________________________ Structures

2. _________________________________ Structures

3. _________________________________ Structures

iv. Homologous Structures

1. ________________________________________________________________________

________________________________________________________________________

2. Evolution predicts that body parts of different organisms are more likely to be modifications

of ancestors than completely new features.

3. Think Pair Share: Can you think of an example?

v. Analogous Structures

1. ________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

2. They show that similar features can evolve independently in similar environments.

3. Think Pair Share: Can you think of an example?

8

vi. Vestigial Structures

1. ________________________________________________________________________

________________________________________________________________________

a. (In other words… things that don’t really work anymore.)

2. Think Pair Share: Can you think of an example?

3. Brainstorm

a. Evolutionary theory predicts that Vestigial Structures will become smaller and

disappear… Why?

vii. Using the terms from comparative anatomy, what type of structures are these?

A) Homologous structures

B) Vestigial structures

C) Analogous structures

viii. Using the terms from comparative anatomy, what type of structures are these?

A) Homologous structures

B) Vestigial structures

C) Analogous structures

9

ix. Using the terms from comparative anatomy, what type of structures are these?

A) Homologous structures

B) Vestigial structures

C) Analogous structures

e. Comparative Biochemistry

i. Biochemistry: ___________________________________________________________________

______________________________________________________________________________

ii. The more DNA 2 organisms have in common, the more proteins they produce that are the same,

so the more similar they are.

iii. For example:

1. Humans have more common DNA with chimps (98%) than with moths (68%).

Chapter 11: The Evolution of Populations

I. Concept 11.1: Genetic Variation Within Populations

a. Genetic Variation

i. Leads to _______________________________ variation, which is necessary for natural selection

ii. Stored in a population’s gene pool

10

iii. Population: ____________________________________

_____________________________________________

_____________________________________________

_____________________________________________

iv. Gene pool: ____________________________________

_____________________________________________

_____________________________________________

_____________________________________________

v. Remember: Natural selection (and thus evolution) is not

random. The environment favors genetic combinations

that contribute to survival and reproductive success. Thus,

some alleles may become more common than others in

the gene pool.

vi. Allele frequencies: _______________________________

______________________________________________

______________________________________________

______________________________________________

b. Sources of Genetic Variation

i. Mutation: _______________________________________________________________________

______________________________________________________________________________

ii. Recombination: _________________________________________________________________

______________________________________________________________________________

II. Concept 11.3: Other Mechanisms of Evolution

a. Gene Flow

i. Gene flow: _____________________________________________________________________

______________________________; occurs when individuals join new populations and reproduce

1. Gene flow keeps neighboring populations similar.

11

2. Low gene flow increases the chance that two populations will evolve into different species.

b. Genetic Drift

i. Genetic drift: ____________________________________________________________________

______________________________________________________________________________

1. Genetic drift causes a loss of genetic diversity.

2. It is most common in small populations.

ii. Types of Genetic Drift

1. Bottleneck Effect

a. Bottleneck effect: can lead to genetic drift;

_________________________________

_________________________________

_________________________________

____________________________ (called

a bottleneck event); population usually rebounds with individuals having many of

the same alleles

2. Founder Effect

a. The founding of a small population can lead to genetic drift.

b. The founder effect is genetic drift that occurs after start of new population.

c. Founder effect: _____________________________________________________

_________________________________________________________________

(whatever traits they have keep getting passed on and on, which can lead to a

change in allele frequency,

so the new population

becomes more and more

different over time)

12

iii. Genetic drift has ______________________________ effects on a population.

1. Less likely to have some individuals that can adapt

2. Harmful alleles can become more common due to chance

c. Sexual Selection

i. The more attractive to the opposite sex, the more likely one is to reproduce and pass on those

genes!

ii. Sexual selection occurs when ______________________________________________________

______________________________________________________________________________.

III. Concept 11.5: Speciation Through Isolation

a. Species: ______________________________________________________________________________

_____________________________________________________________________________________

b. So… how do we come up with new species?

i. Through evolution, _______________________________________ occurs, whereby some

members of a sexually reproducing population change so much that they can no longer produce

fertile offspring with members of the original population.

c. How does the population change so much from the original population?

i. ______________________________________________________________________________

d. Types of Speciation

i. Allopatric Speciation: a __________________________________________________ two or more

populations (mountains, rivers, separate ponds, etc.)

1. AKA geographic isolation

13

2. The separate populations become more and more

different over time – eventually they cannot breed

with each other to produce a fertile offspring

ii. Sympatric Speciation: a ___________________________________________________________

____________________________________________ (happens more in plants)- could come from

behavioral differences- what they eat, etc.

1. AKA reproductive isolation

2. Ancestor species and modern species live together

during the process

3. Evidence found in

insects – apple

maggot flies diverged

into two species

based on the fruit they

ate.

e. Reproductive Isolation

i. Reproductive isolation: prevents gene flow among

populations - condition caused by ___________________

______________________________________________

______________________________________________

______________________________________________

14

IV. Concept 11.6: Patterns in Evolution

a. _____________________________________________________________________________________

_____________________________________________________________________________________

b. Patterns of Evolution

i. Convergent Evolution

1. ________________________________________________________________________

________________________________________________________________________

2. The environments are far apart, but the ecology and climate are similar.

ii. Divergent Evolution

1. AKA Adaptive Radiation

2. _______________________________________________

_______________________________________________

_______________________________________________

3. (Often follows mass-extinction – such as the diversity of

mammals after the extinction of the dinosaurs)

15

iii. Coevolution

1. _____________________________________________

_____________________________________________

_____________________________________________

_____________________________________________

2. Example: comet orchids and the moth that pollinate

3. Foot long flower = foot long tongue of the moth

4. Coevolution often occurs as a beneficial (mutualistic) relationship.

5. Coevolution can also occur in competitive relationships.

c. Extinction

i. Extinction: ______________________________________________________________________

______________________________________________________________________________

ii. Extinctions can occur as slow, __________________________ extinctions that occur continuously

at a very low rate or as _________________ extinctions, which are rare but much more intense.

1. (Mass extinctions destroy many species at the global level, usually due to some

catastrophic event, whereas background extinctions usually affect a few species in a small

area and are caused by local changes in environment.)

Chapter 12: The History of Life

I. Concept 12.4: Early Single-Celled Organisms

a. Where did life originally come from?

i. If Earth’s early atmosphere had a mix of certain gases, organic molecules could have been

synthesized from simple reactions involving those gases in the early oceans. (Amino acids

formed… which formed proteins, and so on down the line).

ii. The First Cells

1. Probably ________________________________

2. Eukaryotes appear in the fossil record about 1.8 Billion

years ago. (Remember: Eukaryotes have organelles.)

16

b. Endosymbiosis

i. Endosymbiosis: _________________________________________________________________

______________________________________________________________________________

ii. _______________________________ and _______________________________ may have

developed through endosymbiosis.

iii. The Endosymbiont Theory

1. Small aerobic prokaryotes were ________________________ by larger prokaryotes, and

eventually had a ___________________________ relationship (they both benefited) …

which led to modern day ______________________________.

2. Evidence: Chloroplasts & mitochondria contain their own DNA – which is circular like

bacteria DNA.

17

Chapter 17: The Tree of Life

I. Concept 17.1: The Linnaean System of Classification

a. Taxonomy

i. Taxonomy: _____________________________________________________________________

______________________________________________________________________________

ii. Taxon: ________________________________________________________________________

______________________________________________________________________________

iii. Binomial nomenclature: ___________________________________________________________

______________________________________________________________________________

1. Uses _________________ words

2. Always written in __________________________

3. Each species has a “first & last” name, or 2 names - two parts are the genus name and

species descriptor

4. Introduced by Carolus ____________________________________

iv. Common names work well in everyday language, but can cause confusion for scientists.

1. Scientific names help scientists to communicate.

2. (Some species have very similar common names. Some species have many common

names.)

18

v. Classification is broken down into _____________ categories, but Linnaeus’

classification system has only _____________ levels.

1. Levels get increasingly specific from kingdom to species.

19

vi. Common Name: The Brown Squirrel

1. Kingdom (Animalia, or “animal”)

2. Phylum (Chordata, or “has a backbone”)

3. Class (Mammalia, or “nurses its young”)

4. Order (Rodentia, or “has long, sharp front teeth”)

5. Family (Scuridae, or “has a bushy tail”)

6. Genus (Tamiasciurus, or “climbs trees”)

7. Species (hudsonicus, or “has brown fur on its back and white fur on its under-parts”)

a. Put it all together: This animal has a backbone, nurses its young, has long sharp

front teeth, a bushy tail, climbs trees and has brown fur on its back and white fur

on its under-parts

b. Use the last 2 (Genus & Species) as scientific name - “First & Last” name,

Tamiasciurus hudsonicus

vii. Linnaean classification system limitations

1. Linnaeus taxonomy doesn’t account for molecular evidence. (The technology didn’t exist

during Linneaus’ time.)

2. Linnaean system based only on physical similarities.

a. Physical similarities are not always the result of close relationships.

b. _________________________________________________________________

_________________________________________________________________

_________________________________________________________________

II. Concept 17.2: Classification Based on Evolutionary Relationships

a. Phylogeny: ____________________________________________________________________________

_____________________________________________________________________________________

b. Phylogenetic tree: a ____________________________

__________________________ that represents the

proposed phylogeny of evolutionary history of a species

or group

20

c. Cladistics: a common method to make _______________

_____________________________________________;

classification based on common ancestry; species placed

in order that they descended from common ancestor

i. Cladogram: an evolutionary tree that specifies the ______________________________________

______________________________________________________________________________

ii. Clade: _________________________________________________________________________

______________________________________________________________________________

iii. Each species in a clade shares some traits with the ancestor. Each species in a clade has traits

that have changed.

iv. Derived characters: traits shared in different degrees by clade members; ____________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

21

d. Molecular Data

i. Molecular data may confirm classification based on physical similarities.

ii. Molecular data may lead scientists to propose a new classification.

III. Concept 17.4: Domains and Kingdoms

a. Grouping Species

i. The current tree of life has 3 domains:

1. ________________________________________________________________________

ii. Within these domains, there are 6 kingdoms:

1. ________________________________________________________________________

________________________________________________________________________

22

b. Domain Bacteria

i. Kingdoms within this domain: ____________________________________________

1. ____________________________________________

2. ____________________________________________

3. ________________________________________________________________________

ii. There are more bacteria in your body than there are people in the world!

c. Domain Archaea

i. Kingdoms within this domain: ____________________________________________

1. Cell walls chemically different from bacteria

2. Differences discovered by studying RNA

3. ________________________________________________________________________

4. Known for living in extreme environments (hot, salty, no oxygen, etc.)

d. Domain Eukarya

i. Kingdoms within this domain: _______________________________________________________

______________________________________________________________________________

1. ____________________________________________

2. ________________________________________________________________________

23

ii. Kingdom Protista

1. ____________________________________________

2. ________________________________________________________________________

3. Do not have organs

4. 3 Main Examples:

a. Algae (plant-like, photosynthetic)

b. Protozoans (animal-like, heterotrophs)

c. Fungus-like (mold/mildew)

iii. Kingdom Fungi

1. ________________________________________________________________________

2. absorbs nutrients from its environment (digestion occurs outside the organism)

3. ____________________________________________

4. have cell walls (like plants)

5. immobile

iv. Kingdom Plantae

1. ____________________________________________

2. have cell walls (made of cellulose)

3. most are ______________________________________ (with chloroplasts)

4. immobile (many possess roots, stems & leaves)

v. Kingdom Animalia

1. ____________________________________________

2. ____________________________________________

e. Viruses

i. Viruses are nucleic acid surrounded by a protein coat.

1. Are they living???

a. 7 Characteristics of Life:

i. Made of Cells, Grows & Develops, Reproduces, Responsive, Requires

Energy (Metabolism), Homeostasis, Adapts over time

2. Because ________________________________________________________________,

they do not have a place in the scientific system of classification of life.