Transcript Chapter 7 Changes Over Time

Chapter 7 Changes Over Time
Table of Contents
Chapter Preview
7.1 Darwin’s Theory
7.2 Evidence of Evolution
7.3 Evolution of Species
7.4 Classifying Organisms
7.5 Branching Trees
Chapter 7 Changes Over Time
Chapter Preview Questions
1. Compared to body cells, the cells that result from meiosis
have
a. half the number of chromosomes.
b. the same number of chromosomes.
c. double the number of chromosomes.
d. triple the number of chromosomes.
Chapter 7 Changes Over Time
Chapter Preview Questions
1. Compared to body cells, the cells that result from meiosis
have
a. half the number of chromosomes.
b. the same number of chromosomes.
c. double the number of chromosomes.
d. triple the number of chromosomes.
Chapter 7 Changes Over Time
Chapter Preview Questions
2. Which is true of the alleles for a gene?
a. There are only two alleles for every gene.
b. The alleles are always identical.
c. The alleles are never identical.
d. One allele may be dominant.
Chapter 7 Changes Over Time
Chapter Preview Questions
2. Which is true of the alleles for a gene?
a. There are only two alleles for every gene.
b. The alleles are always identical.
c. The alleles are never identical.
d. One allele may be dominant.
Chapter 7 Changes Over Time
Chapter Preview Questions
3. An organism’s traits are determined by its
a. carbohydrates.
b. DNA.
c. mitochondria.
d. chloroplasts.
Chapter 7 Changes Over Time
Chapter Preview Questions
3. An organism’s traits are determined by its
a. carbohydrates.
b. DNA.
c. mitochondria.
d. chloroplasts.
Chapter 7 Changes Over Time
Chapter Preview Questions
4. Where do sexually reproducing organisms inherit their
alleles from?
a. half from each parent
b. mostly from their mother
c. mostly from their father
d. only from their mother
Chapter 7 Changes Over Time
Chapter Preview Questions
4. Where do sexually reproducing organisms inherit their
alleles from?
a. half from each parent
b. mostly from their mother
c. mostly from their father
d. only from their mother
Chapter 7 Changes Over Time
What factors have caused the evolution and diversity of
organisms?
You plant a packet of zinnia
seeds, and later, the zinnias
begin to bloom. You notice that
no two plants are exactly alike.
For example, some flowers have
different colors than others. What
accounts for these differences?
Write an explanation.
Chapter 7 Changes Over Time
Identify Multiple Meanings
Word
Everyday Meaning
Scientific Meaning
n. A guess; an idea of how
or why something might
happen
n. A well-tested concept that
explains a wide range of
observations
Example: Emily has a
theory that basketball is
harder to play than baseball.
Example: The cell theory says
that all organisms are made of
cells.
theory
Chapter 7 Changes Over Time
Identify Multiple Meanings
Word
Everyday Meaning
Scientific Meaning
n. A device that protects a
broken bone by
preventing it from moving
n. A type of fossil that forms
when a mold becomes filled
with minerals
Example: Tim's broken
elbow has healed, so the
cast can be removed.
Example: The cast of the
foot print shows that the
extinct animal had five toes.
cast
Chapter 7 Changes Over Time
Apply It!
In the sentences below, identify which meaning of the word
theory was used—the everyday meaning or the scientific
meaning.
1.
The theory of evolution explains how organisms have changed
over time.
Theory (science use)
2.
Do you have a theory about why Sarah is a vegetarian?
Theory (everyday use)
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Changes Over Time
End of Chapter
Preview
Chapter 7 Changes Over Time
Changes Over Time
Section 1:
Darwin’s Theory
What important observations did Darwin make on his
voyage?
How did Darwin account for the diversity of species
and the differences between similar species?
How does natural selection lead to evolution?
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Changes Over Time
Darwin’s Voyage
Charles Darwin sailed on the Beagle, from England to the
Galápagos Islands.
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Changes Over Time
Overproduction and Variation
Natural selection is the process by which individuals who are
better adapted to their environment are more likely to survive
and reproduce than other members of the same species.
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Changes Over Time
Competition and Selection
Variations among turtles make some of them better able to
survive. Turtles that survive to become adults will be able to
reproduce.
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Changes Over Time
End of Section:
Darwin’s Theory
Chapter 7 Changes Over Time
Section 2:
Evidence of Evolution
What evidence supports the theory of evolution?
How do fossils form?
What do scientists learn from fossils?
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Homologous Structures
The structure of the bones in a dolphin’s flipper, a bird’s
wing, and a dog’s leg is similar. Homologous bones are
shown in the same color.
Chapter 7 Changes Over Time
How Do Fossils Form?
Most fossils form when organisms that die become buried in
sediments.
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Changes Over Time
The fossils record provides
evidence about the history of
life and past environments on
Earth. In addition, scientists
use fossils to study the rate at
which evolution has occurred.
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End of Section:
Evidence of
Evolution
Chapter 7 Changes Over Time
Section 3:
Evolution of Species
What factors have contributed to the diversity of
species?
How do new species form?
How do scientists infer evolutionary relationships
among species?
What causes the extinction of species?
Chapter 7 Changes Over Time
Kaibab and Abert’s Squirrels
These two kinds of squirrels have
been isolated from one another
for a long time. Eventually this
isolation may result in two
different species.
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A Branching Tree
This branching tree shows how scientists now think that
raccoons, lesser pandas, giant pandas, and bears are
related.
Chapter 7 Changes Over Time
Extinction of Species
Extinction is caused by a
change in species'
environment. The
members of a species
may not have adaptations
that allow them to survive
and reproduce in the
changed environment.
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End of Section:
Evolution of Species
Chapter 7 Changes Over Time
Section 4:
Classifying Organisms
Why do biologists organize living things into groups?
What do the levels of classification indicate about the
relationship between organisms?
What characteristics are used to classify organisms
into domains and kingdoms?
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Levels of Classification
As you move down the levels of classification, the number of
organisms decreases. The organisms at lower levels share
more characteristics with each other.
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Three Domains of Life
In the three-domain system of classifications, all known
organisms belong to one of three domains–Bacteria,
Archaea, or Eukarya.
Bacteria
Archaea
Eukarya
Protists
Fungi
Plants
Animals
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End of Section:
Classifying
Organisms
Chapter 7 Changes Over Time
Section 5:
Branching Trees
How does a branching tree diagram show
evolutionary relationships?
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A Branching Tree
Branching trees such as this show relationships between
groups of organisms. It also shows the order in which
specific characteristics may have evolved.
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Shared Derived Characteristics
A branching tree diagram shows evolutionary relationships
by grouping organisms according to shared derived
characteristics.
Amphibians
Fishes
Reptiles
Egg with shell
Invertebrates
Four limbs
Backbone
Ancestor of animals
Chapter 7 Changes Over Time
Data for a Branching Tree Diagram
Characteristics of Plants
Plant
True Roots
Seeds
Flowers
Moss
No
No
No
Fern
Yes
No
No
Spruce tree
Yes
Yes
No
Apple tree
Yes
Yes
Yes
The data in the table show
shared derived characteristics of
different types of plants.
Chapter 7 Changes Over Time
Data for a Branching Tree Diagram
Interpreting Data
Characteristics of Plants
Plant
True Roots
Seeds
Flowers
Moss
No
No
No
Fern
Yes
No
No
Spruce tree
Yes
Yes
No
Apple tree
Yes
Yes
Yes
Do mosses have any of the
characteristics indicated at the
top of the table?
No
Chapter 7 Changes Over Time
Data for a Branching Tree Diagram
Interpreting Data
Characteristics of Plants
Plant
True Roots
Seeds
Flowers
Moss
No
No
No
Fern
Yes
No
No
Spruce tree
Yes
Yes
No
Apple tree
Yes
Yes
Yes
Which plant has the greatest
number of the characteristics?
The apple tree
Chapter 7 Changes Over Time
Data for a Branching Tree Diagram
Drawing Conclusions
Characteristics of Plants
Plant
True Roots
Seeds
Flowers
Moss
No
No
No
Fern
Yes
No
No
Spruce tree
Yes
Yes
No
Apple tree
Yes
Yes
Yes
Use the information in the
table to draw a branching tree.
(Hint: Mosses go at the base
of the tree.)
The organisms will branch
off in the order listed, with
moss branching off at the
bottom and the apple tree at
the top.
Chapter 7 Changes Over Time
Data for a Branching Tree Diagram
Inferring
Characteristics of Plants
Plant
True Roots
Seeds
Flowers
Moss
No
No
No
Fern
Yes
No
No
Spruce tree
Yes
Yes
No
Apple tree
Yes
Yes
Yes
A fossil plant shows evidence
of flowers. Where in the
diagram would the plant go?
With the apple tree
Chapter 7 Changes Over Time
End of Section:
Branching Trees