Download Evolution Intro

2/6 Bell Work
A well known fashion designer wanted to escape the hectic
big city. She decided to spend a few days at a rural resort.
She felt like a stroll to relax. That was the last time anyone
saw her alive. The autopsy revealed that the pack on her
back caused her death.
 How could a pack have killed her?
 HINT: Think about different definitions for pack.
2/6 Schedule
 Finish “Teach Every Child About Food” and discussion
 Notes Ch 16.1 “Developing a Theory”
 Dir Rdg Ch 16 “Evolution”
Assignments:
1. Dir Rdg Ch 16 “Evolution” due TBA
Jamie Oliver: “Teach Every Child about Food”
 Are you more likely to be murdered, die from obesityrelated problems, or get lung cancer from smoking?
 Name two of his problems with “Main Street” food.
 What are at least two difficulties school lunch programs
face?
 According to him, why should students learn to cook?
Veggie Evolution
 Identify as many of the plants as possible.
 Compare and contrast them.
Veggie Evolution
 All of the plants on the previous slide were bred from
Brassica oleracea. Humans are Homo sapiens.
 What do these names have in common?
Unit: Evolution
Objectives:
1. Define and describe natural selection.
2. Explain how adaptations and genetic changes lead to
speciation over time.
Evolution Intro
Make a list of some characteristics of birds that could
provide information about their diets.
Ch 16.1 “Developing a
Theory”
Objectives
 Define natural selection.
 Describe the evolution of Darwin’s Theory.
A Theory to Explain
Change over Time
Origin of Species (2 views)
 Christian: species have always existed as they are now
 Darwin presented evidence that evolution happens, and
has changed over time.
 Evolution is the process by which species may change
over time.
Darwin’s Ideas from
Experience
The Voyage of the Beagle
 Darwin’s first evidence was gathered during a global voyage
on the Beagle.
 He was a naturalist and collected natural objects from each
place that he visited.
 He collected fossils and noticed that they were similar to
living organisms.
Darwin’s Voyage
Darwin’s Ideas from
Experience
The Voyage of the Beagle
 Most famous discoveries were made on the Galápagos
Islands.
 Finches
 Several species
 Beaks similar, but specialized for a particular food
 Similar to South American finches
Darwin’s Finches
Darwin’s Ideas from
Experience
The Voyage of the Beagle
 He suggested that all of the finches descended from one
ancestral species that migrated from South America.
 The descendants were modified over time as groups
survived by eating different food.
 Darwin called this descent with modification.
Darwin’s Ideas from
Experience
Years of Reflection
 Darwin spent years studying his data and other sciences
before reporting his ideas about evolution. He needed a
strong explanation.
 Beagle voyage (1831)
 Book published (1859)
 Theory widely accepted (1870s)
Reactions to his
theories were mixed.
2/7 Bell Work
Put in math symbols to make the following equation true.
18 X 12 / 2 + 3 = 111
2/7 Schedule
 Notes Ch 16.1 “Developing a Theory”
 Forks n Beans Lab
 Dir Rdg Ch 16 “Evolution”
Assignments:
1. Dir Rdg Ch 16 “Evolution” due TBA
Darwin’s Ideas from
Experience
Breeding and Selection
 Darwin took interest in the practice of breeding dogs,
cats, crops, etc., especially exotic pigeons.
 Eventually, he realized: breeders take advantage of
natural variation in traits within a species.
Darwin’s Ideas from
Experience
Breeding and Selection
 If a trait can be inherited, breeders can produce more
individuals with the trait.
 Artificial selection : done by humans and not by natural
causes.
Loyal, large, loose
skin…great protectors
short legs to chase badgers down holes
Darwin’s Ideas from
Others
 Darwin was influenced by ideas from the fields of
natural history, economics, and geology.
 The ideas of Lamarck, Malthus, Cuvier, and Lyell were
especially important.
Darwin’s Ideas from
Others
Lamarckian Inheritance
 In 1809, the French scientist Jean Baptiste Lamarck proposed
an explanation for how organisms may change.
 He noticed that each organism is usually well adapted to its
environment.
 He proposed that organisms change over time as they adapt to
changing environments.
Darwin’s Ideas from
Others
Lamarckian Inheritance
 Lamarck was incorrect about inheritance. He proposed
that changes due to use or disuse of a character would be
passed on to offspring.
 This idea was eventually disproved. Darwin accepted
this idea because it proposed a role for inheritance in
evolution.
Darwin’s Ideas from
Others
Population Growth
 In 1798 Malthus, an English economist, observed that
human populations were increasing faster than the food
supply.
 Malthus pointed out that food supplies were increasing
linearly while populations were exponential.
Darwin’s Ideas from
Others
Population Growth
 In contrast, the number of people was increasing
exponentially.
 Malthus noted that the number of humans could not
keep increasing in this way, eventually people would
start to stabilize.
 What is the term for the maximum number of living
things a place can support?
Darwin’s Ideas from
Others
Population Growth
 Darwin saw that all kinds of organisms tend to produce
more offspring than can survive. So, all populations must
be limited by their environments.
Why It Matters -- Dogs
Over time, people bred dogs from wolves for certain physical
and behavior traits. Today breeds are known for their
appearance, behavior traits, and… quirks.
 Can you guess what these dogs were originally bred for?
 Sharpei, Pomeranian, Corgi, Rat Terrier, Poodle
 Which was a companion, sled dog, hunter, herder, guard
dog?
Why It Matters -- Dogs
Most people pick dogs that fit their lifestyles in size,
personality, amount of care needed, etc.
 If you could create a new breed of dog, what traits
would you select for? Why? (4-6 sentences)
 Name of breed
 Physical (size, coat, height,…)
 Personality (very friendly, loyal, protective, tough, etc.)
 Purpose and explanation (guard dog, companion,
herder…)
 Draw It
Forks ‘n Beans Data
Utensil
People
Beans
2/8 Bell Work
Shadow drove into the Speedy Service Station and pulled up
to the pumps. “Fill it up please,” said Shadow. “This may
sound strange,” said the owner, “but I’d rather fill up two cars
from out of town than one car from this town.” Shadow
looked at the man and replied, “I know just what you mean.”
 Why does his statement make sense, economically
speaking?
2/8 Schedule
 Notes Ch 16.2 “Applying Darwin’s Ideas”
 Work Time
 Finish Forks n Beans Lab due THURSDAY
 Dir Rdg Ch 16 “Evolution”
Open House TONIGHT
• 4-7 pm
• Athletics meeting
• Burgers
Assignments:
1. Dir Rdg Ch 16 “Evolution” due TBA
2. Forks n Beans Lab due THURSDAY
Ch 16.2 “Applying
Darwin’s Ideas”
Objectives
 Explain why Darwin’s ideas are widely accepted.
 Identify strengths and weaknesses to Darwin’s arguments.
Why Fossils?
How do you think studying fossils can tell you about how an
organism lived?
Evolution by Natural
Selection
Darwin’s key idea… natural selection
 Individuals that have traits that better suit their
environment are more likely to survive.
 They also tend to produce more offspring than others.
Evolution by Natural
Selection
Steps in Darwin’s Theory
 The theory predicts that the number of individuals that
carry good traits will increase in a population.
Evolution by Natural
Selection
Steps in Darwin’s Theory
1. Overproduction
Every population is capable of producing more offspring
than can possibly survive.
2. Variation
Variation exists within every population. Much of this
variation is in the form of inherited traits..
Evolution by Natural
Selection
Steps in Darwin’s Theory
3. Selection
In a given environment, having a particular trait can make
individuals more or less likely to survive. So, some
individuals leave more offspring than others do.
4. Adaptation
Traits that improve survival and reproduction will become
more common over time.
Natural Selection
Evolution by Natural
Selection
Selection and Adaptation
 Each species becomes adapted to its
environment as a result of living in it
over time.
 Darwin’s theory explains evolution as
a gradual process of adaptations.
Adaptations created
kangaroos, koalas, and
Tasmanian devils from a
common ancestor.
Evolution by Natural
Selection
Selection and Adaptation
 Note that Darwin’s theory refers to POPULATIONS and
SPECIES—not individuals—as the units that evolve.
Evolution by Natural
Selection
Publication of the Theory
 Darwin’s book On the Origin of Species by Means of Natural
Selection presented evidence that evolution happens and
offered a logical explanation of how.
 Biologists began to accept that evolution occurs and that
natural selection helps explain it.
What Darwin Explained
The Fossil Record
 You can infer past events by looking at fossils.
 Sometimes, comparing fossils and living things reveals a
pattern of gradual change.
 Darwin noticed these patterns, but he was aware of
many gaps.
What Darwin Explained
The Fossil Record
 Darwin predicted that intermediate forms between groups
of species might be found.
archeopteryx… bird
or dinosaur?
Evolution on “Islands”
 Evolution in Lake Malawi (Africa) cichlids.
What Darwin Explained
Biogeography
 Generally, scientists have found that the movement of
landforms in Earth’s past helps to explain patterns in the
types and locations of both living and fossil organisms.
Fossil map
What Darwin Explained
Developmental Biology
 The ancestry of organisms is also evident in developing
embryos.
 Compare the development of species to look for similar
patterns.
 Similarities often derive from an ancestor that the species
have in common.
What Darwin Explained
Developmental Biology
 EX: all animals with a backbone (vertebrates),
embryos have a tail at some time.
 Based on this and similar internal structures…
ALL vertebrates had a common ancestor.
2/9 Bell Work
 Create an equation with addition and exponents that
equals 9.
2/9 Schedule
 Notes Ch 16.2 “Applying Darwin’s Ideas”
 Start Natural Selection Simulation
 Work Time
 Finish Forks n Beans Lab due TODAY
 Dir Rdg Ch 16 “Evolution”
Assignments:
1. Dir Rdg Ch 16 “Evolution” due TBA
2. Forks n Beans Lab due TODAY
What Darwin Explained
Anatomy
 When modern vertebrates are compared, the difference
in the size, number, and shape of their bones is clear. Yet
the basic pattern of bones is similar.
 In particular, the forelimbs of many vertebrates are
composed of the same basic groups of bones.
What Darwin Explained
Anatomy
 Homologous structures: characteristics that are similar
in two or more species and that have been inherited from
a common ancestor of those species.
What Darwin Explained
Biochemistry
 Genes can change by mutation and that such change can
make new varieties appear.
 Natural selection may “select against” some varieties
and so “favor” others.
What Darwin Explained
Biochemistry
 A comparison of DNA or amino-acid sequences shows
that some species are more genetically similar than
others.
 These comparisons are more evidence of hereditary
relationships among the species.
Evaluating Darwin’s Ideas
Strengths
1. Evidence, data, numbers!
2. Presented a logical and testable mechanism that could
account for the process of evolution.
Evaluating Darwin’s Ideas
Strengths
3. Changed the way scientists thought about the diversity of
life.
 Before Darwin, most scientists saw species as stable and
unchanging.
 They classified species based on average appearances
and ignored variation.
Evaluating Darwin’s Ideas
Weaknesses
1. Darwin’s explanations contain very little about genetics.
2. Darwin’s theory lacked a clear mechanism for
inheritance.
 Mendel’s mechanism wasn’t widely published until 1900.
2/10 Bell Work
 Solve the word puzzles.
2/10 Schedule
 Natural Selection Simulation
 Finish Gen 3 TODAY
 Work smart!
Assignments:
1. Dir Rdg Ch 16 “Evolution” due TBA
2. Forks n Beans Lab due LATE
2/13 Bell Work
 Solve the word puzzles.
2/13 Schedule
 Quiz Ch 16.1-16.2 in desk groups
 Natural Selection Simulation
 Finish Collecting data TODAY
 Work smart! Due TUESDAY
Assignments:
1. Dir Rdg Ch 16 “Evolution” due TBA
2. Forks n Beans Lab due LATE
3. Natural Selection Simulation - TUESDAY
2/14 Bell Work
Heigh ho, heigh ho, it’s off to school you go…Disney
released its first full-length animated film in 1938.
 Name the film.
2/14 Schedule
 Grade sheets and letters home due THURSDAY
 Quiz Ch 16.1-16.2?
 Natural Selection Simulation due TODAY
 Notes Ch 16.3 “Beyond Darwinian Theory”
Assignments:
1. Dir Rdg Ch 16 “Evolution” due THURSDAY
2. Forks n Beans Lab due LATE
3. Natural Selection Simulation – TODAY
4. Signed Letter and Grade Sheet - THURSDAY
Think About It…
Which do you think evolve faster, short-lived species or
long-lived ones? Why?
Ch 16.3 “Beyond
Darwinian Theory”
 Identify how Darwin’s theory has changed over time.
 Describe different scales for studying evolution.
Darwin’s Theory Updated
Changes to Darwin’s Theory
 1900: Genetics, Mendel’s Law of Heredity
 1940s: Scientists begin to combine Darwin’s theory
together with newer studies of fossils, anatomy, and
genetics.
 Natural selection isn’t the only option.
Darwin’s Theory Updated
Changes to Darwin’s Theory
 Survival and reproduction can be limited by chance or
by the way that genes work in addition to natural
selection.
Some species respond
well to changes, others
don’t.
Darwin’s Theory Updated
Remaining Questions
Can an individual evolve?
They may respond to outside forces, but individuals do not pass
on their RESPONSES as traits. Populations evolve when natural
selection acts (indirectly) on genes.
Click the picture for
another example of crow
problem solving.
Darwin’s Theory Updated
Remaining Questions
Is evolution the survival of the fittest?
Natural selection can act only on the heritable variation.
Chance variations do not always provide the best adaptation
for a given time and place. So, evolution just allows those that
“fit” well enough to leave offspring.
Who survives
better in the
grasslands?
Darwin’s Theory Updated
Remaining Questions
Is evolution predictable?
Not really…evolution sometimes results in larger or morecomplex forms of life, but sometimes simpler.
Snake born with vestigial legs.
Studying Evolution at All
Scales
Different levels of evolution.
 Microevolution: change in genes.
 Macroevolution: appearance of new species over time.
Studying Evolution at All
Scales
Processes of Microevolution
 Looks at the processes by which inherited traits change
over time in a population.
 Five major processes—





natural selection
migration
mate choice
mutation
genetic drift.
Studying Evolution at All
Scales
Processes of Microevolution
 Natural Selection
Natural selection can cause an increase or decrease in
certain alleles in a population.
Studying Evolution at All
Scales
Processes of Microevolution
 Migration
Migration is the movement of individuals into, out of, or
between populations. Migration can change the numbers
and types of alleles in a population.
Studying Evolution at All
Scales
Processes of Microevolution
 Mate Choice
If parents are paired up randomly in a population, traits
will be passed on randomly. If parents are limited or
selective in their choice of mates, a limited set of traits
will be passed on.
Studying Evolution at All
Scales
Processes of Microevolution
 Mutation
Mutation can change the numbers and types of alleles
from one generation to the next. Such changes are rare.
Recessive mutant white Bengal tiger.
Studying Evolution at All
Scales
Processes of Microevolution
 Genetic Drift
The random effects of everyday life can cause differences
in the survival and reproduction of individuals. Some
alleles may become more or less common in a
population, especially in a SMALL population.
Studying Evolution at All
Scales
Patterns of Macroevolution
 Coevolution
Organisms are part of one other’s environment, so they
can affect one another’s evolution.
Studying Evolution at All
Scales
Patterns of Macroevolution
 Adaptive Radiation
Over time, species may split into two or more lines of
descendants, or lineages.
Studying Evolution at All
Scales
 Describe the adaptive radiation you see in these giraffes.
Studying Evolution at All
Scales
 Is a giraffe’s neck long or short?
 Answer… it depends on the situation
Studying Evolution at All
Scales
Patterns of Macroevolution
 Extinction
If all members of a lineage die off or simply fail to
reproduce.
Moving Lions
Answer the questions.
 What would happen if we moved a community of lions to
Arizona?
 What would they eat?
 Would anything eat them? Which lions would survive and
why?