Name: Date:

Unit 10: Speciation

Students will be able to:

10.1 The student will be able to analyze and explain how the mechanisms of evolution result in the emergence and extinction of species.

Definition of a biological species

Explain how speciation may occur as a result of different types of isolation, including: behavioral, reproductive, temporal, and gametic isolation

Discuss how the components of natural selection leads to new species over time

o Selective advantage in competition for survival and reproduction

o Adaptation and variation in genetics leads to speciation

Explain how environmental pressures result in convergent and divergent patterns of evolution.

Discuss human evolution and how we became a separate species.

10.2 The student will be able to explain how new species emerge in predictable patterns

Discuss the classification of different species

o Understand the 8 levels of the modern classification system and the two-word naming

system called binomial nomenclature

o Discuss evolutionary classification including:

Common Ancestors

Clades

DNA

o Use multiple factors to build a cladogram to show the relationship between different

species.

Discuss how using multiple factors to compare species strengthens or weakens

the cladogram.

Keywords:

Species

Speciation

Geographic Isolation

Temporal Isolation

Behavioral Isolation

Reproductive

Isolation

Mechanical Isolation

Sexual Selection

Molecular Clock

Neutral mutations

Duplicate Genes

Gene family

Classification

Taxonomy

Binomial

nomenclature

Taxon

Cladogram

Derived

characteristics

Outgroup

Lineage

Common Ancestor

Convergent

Evolution

Divergent Evolution

Coevolution

Gradualism

Punctuated

Equilibrium

Adaptive Radiation

2

Speciation Unit

Date Topic

4/29 Rise of the Vertebrates Video

4/30 Speciation Notes and Practice

5/1 Molecular Evolution Annotated Reading

5/2 Speciation Lab

5/3 Classification Activity

5/6 Classification Notes

5/7 Cladogram Notes

5/8 Cladogram Practice

5/9 Cladogram Practice

5/10 Human Evolution

5/13 Human Evolution

5/14 Patterns of Evolution Notes and Practice

5/15 Unit Review

5/16 Unit 9 and 10 Free Response Question

5/17 Unit 10 Multiple Choice Test

5/20 Semester Review

5/21 Semester Review

5/22-5/23 Semester Finals

4/29/19

Objective: Students will be able to explain the mechanisms that give rise to new species.

Warm-Up: None

4/30/19

Objective: Students will be able to explain the mechanisms that give rise to new species.

Warm-Up:

1. What are two things I want you to know by the end of this unit?

2. When is your unit test?

10.1 Speciation and Mechanisms of Speciation

Species

A species is a population whose members can interbreed and

.

o : the formation of a new species through evolution.

3

Example: Darwin’s Finches

Mechanisms of Speciation: Isolation

: live in different habitats, rarely see each other.

: two species breed during different times of

the day, different seasons or different years.

o Example: Two related frog species, Rana aurora and Rana boylii, breed during different

times of the year.

: special signals attract mates, elaborate

behaviors attract mates

: the existence of biological factors that impede

members of two species from producing viable, fertile hybrids

o Sperm of one species, not able to survive in female of other species.

: they can try but are anatomically incompatible

Sexual Selection

Mating choices can change the composition of a population over time. “

”

o In this case, traits help an organism survive in a particular

environment, but rather help an organism find a !

2 methods:

o : females selecting males for their

“attractiveness”

o : males competing with males for

females.

Note: there are exceptions to this based on species

Cost of Sexual Selection

o Many organisms expend a lot of to get mates:

Large showy tails in peacocks

Seals fight for territories

Males build large, showy nests

o Some organisms have features to attract mates but are harmful to their survival (ie also

attract )

Large antlers of moose

Bright coloration in cardinals

Long tail feathers in pheasants

Benefits of Sexual Selection

o

Get to pass along their genes!

o

The chance of bearing offspring that will survive and also reproduce.

Parental help

Good territory

o !

4

5/1/19

Objective: Students will be able to describe how we use mutations in the DNA to trace evolutionary

lineage of species.

Warm-Up:

1. Explain why reproductive isolation must occur for separate populations of the same species to

evolve into different species.

2. Use the following phrases to identify each process that leads to speciation.

Founders Arrive

Changes in the gene pool

Competition

Geographic Isolation

Behavioral Isolation

Process How it leads to speciation

A population arrives in a new place.

Populations are separated by a geographic barrier and do not

share a gene pool.

Populations evolve new traits in response to natural selection in

their environments.

Species evolve in a way that reduces competition between them.

Groups within a population are separated by different courtship

rituals.

10.2 Molecular Evolution

As you read:

Underline key ideas

Define and draw a picture of the vocabulary words

Put a question mark next to ideas you don’t understand of want to know more about.

Answer the questions in the boxes.

Think About It Recall that an organism’s genome is its complete set of genetic information.

Thousands of ongoing projects are analyzing the genomes of organisms ranging from viruses to humans.

The analysis of genomes enables us to study evolution at the molecular level. By comparing DNA

sequences from all of these organisms, we can often solve important evolutionary puzzles. For example,

DNA evidence may indicate how two species are related to one another, even if their body structures

don’t offer enough clues.

5

Timing Lineage Splits: Molecular Clocks What are molecular clocks?

When researchers use a molecular clock, they compare stretches of

DNA to mark the passage of evolutionary time. A molecular clock uses

mutation rates in DNA to estimate the time that two species have

been evolving independently.

Neutral Mutations as “Ticks” To understand molecular clocks,

think about old-fashioned pendulum clocks. They mark time with a

swinging pendulum. A molecular clock also relies on a repeating

process to mark time-mutation. As you’ve learned, simple mutations

occur all the time, causing slight changes in the sequence of DNA. Some

mutations have a major positive or negative effect on an organisms’

phenotype. These types of mutations are under powerful pressure from

natural selection.

Many mutations, however, have no effect on phenotype. These

neutral mutations tend to accumulate in the DNA of different species at

about the same rate. Researchers can compare such DNA sequences in two species. The comparison

can reveal how many mutations have occurred independently in each group, as shown in the figure

below. The more differences there are between the DNA sequences of the two species, the more time

has elapsed since the two species shared a common ancestor.

1. Which kind of mutation-neutral or negative-will most likely persist in a population over time?

Explain your answer.

Vocabulary:

Molecular Clock:

Picture:

Neutral Mutations:

Picture:

6

Calibrating the Clock The use of molecular clocks is not simple, because there is not just one

molecular clock in a genome. There are many different clocks, each of which “ticks” at a different rate.

This is because some genes accumulate mutations faster than others. These different clocks allow

researchers to time different evolutionary events. Think of a conventional clock. If you want to time a

brief event, you use the second hand. To time an event that lasts longer, you use the minute hand or

the hour hand. In the same way, researchers choose a different molecular clock to compare great apes

than to estimate when mammals and fishes shared a common ancestor.

Researchers check the accuracy of molecular clocks by trying to estimate how often mutations

occur. In other words, they estimate how often the clock they have chosen “ticks”. To do this, they

compare the number of mutations in a particular gene in species whose age has been determined by

other methods.

Gene Duplication Where do new genes come from?

Where did the roughly 25,000 working genes in the human genome come from? Modern genes

probably descended from a much smaller number of genes in the earliest life forms. But how could that

have happened? One way in which new genes evolve is through the duplication, and then

modification, of existing genes.

Copying Genes Most organisms carry several copies of various genes. Sometimes organisms carry

two copies of the same gene. Other times, there may be thousands of copies. Where do those extra

copies come from, and what happens to them?

Remember that homologous chromosomes exchange DNA during meiosis in a process called

crossing-over. Sometimes crossing-over involves an unequal swapping of DNA. In other words, one

chromosome in the pair gets extra DNA. That extra DNA can carry part of a gene, a full gene, of a longer

length of chromosome. Sometimes, in different ways, an entire genome can be duplicated.

Duplicate Genes Evolve What’s so important about gene duplication? Think about using a

computer to write an essay for English class. You then want to submit a new version of the essay to

your school newspaper. So, you make an extra copy of the original file and edit it for the newspaper.

Duplicate genes can work in similar ways. Sometimes, extra

copies of a gene undergo mutations that change their function. The

original gene is still around, just like the original copy of your English

essay. So, the new genes can evolve without affecting the original

gene function or product. The figure to the right shows how this

happens.

7

Gene Families Multiple copies of a duplicated gene can turn

into a group of related genes called a gene family. Members of a

gene family typically produce similar, yet slightly different,

proteins. Your body, for example, produces a number of

molecules that carry oxygen. Several of these compounds-called

globins-are hemoglobins. The globin gene family that produces

them evolved, after gene duplication, from a single ancestral

globin gene. Some of the most important evolution research

focuses on another gene family-Hox genes.

Fishes in Two Lakes

A research team studied two lakes in an area that sometimes

experiences flooding. Each lake contained two types of similar

fishes: a dull brown form and an iridescent gold form. The team

wondered how all the fishes were related, and they considered

the two hypothesis diagramed below.

1. Study the two diagrams. What

does hypothesis A indicate about

the ancestry of the fishes in Lake

1 and Lake 2. What does

hypothesis B indicate?

2. A DNA analysis showed that the

brown and gold fishes from Lake 1 are the most closely related. Which hypothesis does this

evidence support?

Developmental Genes and Body Plans How may Hox genes be involved in evolutionary change?

One exciting new research area is nicknamed “evo-devo” because it studies the relationship between

evolution and embryological development. Darwin himself had a hunch that changes in the growth of

embryos could transform adult body shape and size. Researchers now study how small changes in Hox

gene activity could produce kinds of evolutionary changes we see in the fossil record.

Vocabulary:

Duplicate Genes:

Picture:

Gene Family:

Picture:

8

Hox Genes and Evolution Remember that Hox genes determine which parts of an embryo develop

arms, legs, or wings. Groups of Hox genes also control the size and shape of those structures. In fact,

homologous Hox genes shape the bodies of animals as different insects and humans-even though those

animals last shared a common ancestor no fewer than 500 million years ago!

Small changes in Hox gene activity during embryological development can produce large

changes in adult animals. For example, insects and crustaceans are related to ancient common

ancestors that possessed dozens of legs. Today’s crustaceans, including shrimp and lobsters, still have

large numbers of paired legs, but insects have just 3 pairs of legs. What happened to those extra legs?

Recent studies have shown that mutations in a single Hox gene, known as Ubx, turns off the growth of

legs in the abdominal regions of insects. Thus, a change in one Hox gene accounts for a major

evolutionary difference between two important animal groups.

Timing is Everything Each part of an embryo starts to grow at a certain time, grows for a specific

time, and stops growing at a specific time. Small changes in starting and stopping times can make a big

difference in organisms. For example, small timing changes can make the difference between long,

slender fingers and short, stubby toes. No wonder “evo-devo” is one of the hottest areas in

evolutionary biology!

1. How can HOX genes help reveal how evolution occurred?

5/2/19

Objective: Students will model how organisms undergo speciation.

Warm-Up:

1. Which species is most closely related to Species B? Explain your

answer.

2. How can you tell that Species C is probably not a descendant of the

organism with Gene 2?

9

5/3/19

Objective: Students will classify different objects to simulate the classification of different organisms.

Warm-Up:

1. The members of a particular population of insects live and feed high up in the trunks of trees.

As time passes, some members of the population begin to feed on different parts of the trees.

Eventually, the two groups separate and no longer interbreed. What mechanism of

reproductive isolation does this show?

2. Scientists studied the mating activity of four closely related species of frogs and recorded the

peak mating times of each species. Which two species are the most closely related? Explain

your answer.

Frog Species Peak Mating Time

Leopard Frog First week of April

Pickerel Frog Third week of April

Tree Frog First week of June

Bullfrog First week of July

3. What are two other forms of evidence that could support that these frogs are different species?

Vocabulary Builder: Use the definition to unscramble the vocabulary words. Write the word in the box.

Word Scrambled Word Definition

epsiecs Members of a population who can interbreed and produce fertile offspring.

evhblarioa iinsoltoa Special signals or elaborate behaviors to attract a mate.

mtepaolr slnotiioa Two species breed during different times.

epvrtorucdie nsoliaiot The existence of biological factors that impede members of two species from producing viable, fertile hybrids.

nepiastioc The formation of a new species through evolution.

ecchaanmil aiilnoost Two species are anatomically incompatible.

epoggraich tsonlaiio Populations live in different habitats and rarely see each other.

10

5/6/19

Objective: Students will be able to describe why and how organisms are classified based on many

different factors.

Warm-Up:

1. Why is organization of living organisms important?

2. The mountain lion has many common names: mountain lion, cougar, puma, el leon, and

catamount. Why could using the common name of an organism be confusing?

10.3 Classification

Finding Order in Diversity

is the arrangement of organisms into orderly groups based on

their similarities

Classification is also known as

are scientists that identify and name organisms

Benefits of Classifying

and names organisms

Prevents misnomers such as starfish and jellyfish that aren’t really fish

Uses the (Latin or Greek) for all names

Aristotle’s System

The Greek philosopher grouped all the organisms he knew into

groups: plants and animals.

o He grouped organisms according to their physical structures and their habitat: land, sea,

or air dwellers.

As time passed, more organisms were discovered and some

easily into Aristotle’s groups, but many centuries passed before Aristotle’s system was replaced.

Linnaeus’s System of Binomial Nomenclature

18th Century Taxonomist

Classified organisms by their

Developed the naming system still used today:

o Two-word name ( )

11

o

o Italicized in print

o but not species

o Underline when writing

Classification Groups

o (taxa-plural) is a category into which related organisms are

placed.

o There is a hierarchy of groups (taxa) from broadest to most specific

o , Kingdom, , Class, Order,

, Genus,

Modern Evolutionary Classification

Because classifying organisms based on structure could be problematic, biologists now group

organisms into categories that represent .

o We look for , similar embryo development,

and molecular similarities in , RNA, or the amino acid sequence of proteins.

o Remember that the two organisms in

common-the more they are.

o Example: Crabs, barnacles, limpets

Until about 150 years ago, barnacles and limpets were grouped together

because both had conical shells.

However, we now group them because they share important evolutionary

characteristics, such as: a segmented body and an exoskeleton that the

organisms molts. Limpets do not share these characteristics.

Classification Using Cladograms

A is a diagram that shows how organisms are related

based on and characteristics.

o A is one that appears in recent parts of a

lineage but not in its older members.

o Examples: feathers, hair, or scales

They show a of organisms from ancestral groups.

12

5/7/19

Objective: Students will be able to use shared and derived characteristics to construct a cladogram and

draw conclusions about the evolutionary relationship between living organisms.

Warm-Up: Answer the following questions while watching the short film “The Making of the Fittest: The

Birth and Death of Genes”.

1. How does icefish blood differ from that of other vertebrates?

2. How is the icefish adapted to live in such cold water?

3. How do antifreeze proteins give Nothothenoids a selective advantage?

4. How did the antifreeze gene evolve?

10.4 How to Construct a Cladogram

Quick Review

A cladogram is a diagram that shows how organisms are related based on shared and derived

characteristics.

o A derived characteristic is one that appears in recent parts of a lineage but not in its

older members.

They show a probable evolution of organisms from ancestral groups.

o The more two organisms are related, the they

will be to each other on the tree.

How to Read a Cladogram

The diagram below shows a relationship between 4 relatives.

These relatives share a at the of the

tree.

Note that this diagram is also a timeline. The organism is at

the of the tree.

on the tree represent .

The four descendants at the top of the tree are different species.

13

Example:

o Species A, B, and C each have characteristics that are unique only to them.

o But, they also share some part of their history with species A.

o This shared history is the common ancestor.

How to Construct a Cladogram

1. Select the you want to analyze.

2. For each member of the group, determine some .

a. It is good to choose as many traits to examine as possible. This is because not all traits

may give reliable or useful answers. Thus, to minimize the chance of error, your analysis

should be based on as many traits as possible.

3. Choose an -a group of organisms that is evolutionarily

older than the organisms you are analyzing.

a. Usually the outgroup is the one that has -

it’s the one that does not match!

4. Construct a -this shows the number of identical characters exhibited

by each pair of organisms in your analysis.

5. Identify the organism most to the outgroup-place it

on the cladogram.

a. This is the organism that shares the most characters in common.

6. Place the additional organisms of the tree in order of the shared

characteristics with the outgroup to the shared characteristics with the

outgroup.

5/8/19

Objective: Students will be able to use shared and derived characteristics to construct a cladogram and

draw conclusions about the evolutionary relationship between living organisms.

14

Warm-Up: Examine the cladogram below. Each letter represents a derived character. Match the letter

to its characteristic below.

Wings

6 legs

Segmented body

Double set of wings

Cerci (back appendages)

Crushing mouthparts

Legs

Curly Antennae

5/9/19

Objective: Students will be able to use shared and derived characteristics to construct a cladogram and

draw conclusions about the evolutionary relationship between living organisms.

Warm-Up: Cytochrome c is a protein located in the mitochondira of cells involved with cellular

respiration. Below is a table showing the amino acid sequences for cytochrome c in several organisms.

The more amino acids that an organism has in common, both type and order, indicates the closer the

relationship.

15

1. Compare the biochemical data above. Which organism is most closely related to the lizard?

Why?

2. Which organism is most closely related to the dolphin? Why?

3. What would this look like on a cladogram?

5/10/19

Objective: Students will be able to look at human evolution and be able to discuss how humans became

a separate species over time.

Warm-Up:

1. Which two organisms are more closely related:

hagfish and perch OR perch and lizards?

Explain your answer.

16

2. Which two organisms are more closely related: lizards and pigeons OR mice and chimps? Explain

your answer.

3. Do perch and chimps share a common ancestor? Explain your answer.

5/13/19

Objective: Students will be able to look at human evolution and be able to discuss how humans became

a separate species over time.

Warm-Up:

1. Use the table of derived traits below to draw a cladogram.

Trait

Organism Jaws Lungs Amniotic Membrane

Hair No Tail Bipedal

Lamprey X X X X X X

Shark 1 X X X X X

Salamander 1 1 X X X X

Lizard 1 1 1 X X X

Tiger 1 1 1 1 x X

Gorilla 1 1 1 1 1 X

Human 1 1 1 1 1 1

Cladogram:

17

5/14/19

Objective: Students will be able to explain the patterns of evolution and how species can evolve in

relation to each other.

Warm-Up:

Vocabulary Builder: Define the following words, draw a picture, and describe how you are going to

remember the meaning of the word.

Word Definition Picture How are you going to remember it?

Taxon

Cladogram

Derived Characteristics

Outgroup

Lineage

Common Ancestor

10.5 Patterns of Evolution

Evolution Occurs in Patterns

Evolution through natural selection is .

o Natural selection can have

o The effects of natural selection over time

Patterns of Evolution

: evolution towards

in unrelated species due to a .

o Example: Tuna (fish) and dolphins (mammals). Because they lived in the ocean (a similar

environment) both faced similar evolutionary pressures and developed fins to navigate

the water.

: evolution towards a

in a closely .

18

o Caused by different environments

: two or more species in

response to .

o Evolutionary paths become connected

o Both species receive form the other as a result of

.

o Example: plants and insects

Plants: provide insects with nectar

Insect: transfers pollen from one plant to another

o Can occur in , sometimes called an

.

Example: Crab vs Snail

Extinction:

o

Cause: local changes in the environment

Forest fires, habitat destruction

Affects a few species in a small area

Less severe

Occurs at roughly the as

o

Cause: catastrophic events

Ice ages, meteorites

Very severe

Rare but much more intense

At least 5 mass extinctions in Earth’s history

How fast does evolution occur? No exact time frame!

o of one species into another

Small changes continually build over time

o periods of are

interrupted by periods of .

Due to sudden environment change

Example: Mammal diversity exploded after the dinosaur extinction.

: a process of evolution where one species can

into a number of .

o Ancestral species diversifies into many descendent species.

o Each adapted to a different environment

Example: mammals

19

5/15/19

Objective: Students will demonstrate their knowledge of speciation on a unit review.

Warm-Up:

1. Go back to the front page of this packet and read through the essential outcomes. Put a

question mark next to the topics that you still have questions about. Put a check mark next to

the topics that you feel confident about.

2. How are you going to go about learning those topics that have a question mark next to them?

5/16/19

Objective: Students will demonstrate their knowledge of speciation on a unit free response question.

Warm-Up:

1. None

5/17/19

Objective: Students will demonstrate their knowledge of speciation on a unit test.

Warm-Up:

1. Turn your work in to the basket.