table of contents 7.5 branching trees 7.4 classifying organisms 7.3 evolution of species 7.2...
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Table of Contents
7.5 Branching Trees
7.4 Classifying Organisms
7.3 Evolution of Species
7.2 Evidence of Evolution
7.1 Darwin’s Theory
Chapter Preview
Chapter 7 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 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 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 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 Preview Questions
3. An organism’s traits are determined by its
a. carbohydrates.
b. DNA.
c. mitochondria.
d. chloroplasts.
Chapter Preview Questions
3. An organism’s traits are determined by its
a. carbohydrates.
b. DNA.
c. mitochondria.
d. chloroplasts.
Chapter 7 Preview Questions
4. Where do sexually reproducing organisms inherit their alleles from?
a. half from each parentb. mostly from their motherc. mostly from their fatherd. only from their mother
Chapter 7 Preview Questions
4. Where do sexually reproducing organisms inherit their alleles from?
a. half from each parentb. mostly from their motherc. mostly from their fatherd. only from their mother
Section 7.1: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?
Changes Over Time
Darwin’s Voyage
•Charles Darwin sailed on the HMS Beagle --1831•England to the Galápagos Islands.•He was the ships naturalist•5 years
Changes Over Time
Darwin's Discoveries
Finches had beaks adapted to their diet
Mainland Iguanas had short claws
Those on the islands had long claws
The Galapagos cormorant had lost its ability to fly
The shells of the tortoise differed between the islands.
The Theory of Natural Selection
In 1859 ----Darwin proposed his theory of evolution based on the idea of natural selection.
Natural Selection= the strongest or most fit survive
Overproduction and Variation
Overproduction is when an organism produces too many offspring to increase the chance of survival .
Changes Over Time
Overproduction and Variation
Variation is when offspring have differences .
Each individual that is born will have different characteristics.
These characteristics are heritable
Competition and Selection
Variations among animals can give them traits that can help them survive and reproduce.
Changes Over Time
Section 7.2:Evidence of Evolution
What evidence supports the theory of evolution?
How do fossils form?
What do scientists learn from fossils?
Homologous Structures
Homology is when bones are similar in different organisms.
HOMOLOGOUS STRUCTURES
Homologous structures are one piece of evidence scientists use to prove evolution
FOSSILES
ARCHIOPTERIX- the first bird
TRILOBITES
Index fossils that were alive a short time
How Do Fossils Form?
Most fossils form when organisms that die become buried in sediments.
Changes Over Time
The fossils record provides evidence about …
•past live forms
• past environment.
• rate at which evolution occurred
Section 7.3: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?
Kaibab and Albert's Squirrels
These two kinds of squirrels have been isolated from one another for a long time.
Isolation may result in two different species.
A Branching Tree
This branching tree shows how scientists now think that raccoons, lesser pandas, giant pandas, and bears are related.
Extinction of Species
Extinction is caused by a change in species' environment.
Section 7.4: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?
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.
Three Domains of Life
In the three-domain system of classifications, all known organisms belong to one of three domains–Bacteria, Archaea, or Eukarya.
Protists Fungi Plants Animals
Bacteria Archaea Eukarya
Bacteria
Single celled
No nucleus
prokaryotes
Archaea
Single celled
No nucleus
Prokaryotes
Ancient
Section 5:Branching Trees
How does a branching tree diagram show evolutionary relationships?
A Branching Tree
Branching trees show relationships between groups of organisms.
It also shows the order in which specific characteristics may have evolved.
Shared Derived Characteristics
A branching tree diagram shows evolutionary relationships by grouping organisms according to shared derived characteristics.
ReptilesAmphibians
Egg with shell
Fishes
Four limbs
Backbone
Invertebrates
Ancestor of animals