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.

3

ii. Artificial selection: ________________________________________________________________ b. Natural Selection is: "______________________________________"; a mechanism by which individuals

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

________________________________________________________________________________

d. 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.

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.

e. Darwin’s Theory of natural selection explains how evolution works. He published a book: “On the Origin of Species by Means of Natural Selection.”

4

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.

5

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 organisms 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

6

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?

7

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

8

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%).

9

V. 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 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: _________________________________________________________________

______________________________________________________________________________

10

VI. 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. 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.

11

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)

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 ______________________________________________________

______________________________________________________________________________.

12

VII. Concept 11.5: Speciation Through Isolation a. Species: ______________________________________________________________________________

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

i. Through evolution, speciation 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 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.

13

e. Reproductive Isolation i. Reproductive isolation: prevents gene flow among

populations - condition caused by ___________________ __________________________________________________________________________________________________________________________________________

ii. Two Types of Reproductive Isolation 1. Prezygotic Isolation (before fertilization):

a. Prevents reproduction by making fertilization unlikely

b. Behavioral Isolation: differences in _____________________________________ __________________________ behaviors, leading to difficulty in attracting mates

c. Geographic Isolation: different _________________________________________ _____________________________________________________ the population

d. Temporal Isolation: _________________________________________________ ____________________________ of year

2. Postzygotic isolation (after fertilization): a. Prevents reproduction because ________________________________________

_________________________________________________________________

14

VIII. 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.)

d. Rates of Speciation i. Punctuated equilibrium: _______________________________

______________________________________________________________________________________________________________________________________________________

ii. Gradualism: ________________________________________ __________________________________________________

16

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.) 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.