Chapter 10: Evolution

Section 10.1 Early Ideas about Evolution

Warm-Up1. How can you use the concept of genetic

inheritance to disprove Lamarck’s idea of inheritance of acquired characteristics?

Objectives 1. Students will be able to examine early

ideas about evolution. 2. Students will be able to identify three

geological theories that influenced scientific debates over evolution

Key Concept There were theories of biological and

geologic change before Darwin.

Early Scientists Proposed Ideas About Evolution

What is Evolution? The process of biological change by which

descendants come to differ from their ancestors

Evolution is the central theme of all fields of biology

Early Scientists Proposed Ideas About Evolution

1. Carl Linnaeus Swedish Botanist who developed a

classification system for all organisms know at the time :

Binomial Nomenclature Organisms were grouped by their

similarities and evolutionary relationships

Believed that some organisms developed due to hybridization

Crossing between species Species: a group of organisms so similar to

one another that they can reproduce and have offspring

Early Scientists Proposed Ideas About Evolution

2. George Louis Leclerc de Buffon French naturalist Suggested that species shared ancestors Discussed the sources of biological

evolution

Early Scientists Proposed Ideas About Evolution

3. Erasmus Darwin Charles Darwin’s Grandfather He suggested that all organisms evolved

from a common ancestor More complex life forms developed from

less complex life forms

Early Scientists Proposed Ideas About Evolution

4. Jean-Baptiste Lamarck Believed that all organisms

evolved to become perfect and more complex

Did not believe in the idea of extinction

Changes in the environment could lead to a change in an organisms behavior which can lead to use or disuse of a particular structure or organ

Inheritance of Acquired characteristics

Timeline of Evolution

1735:Linnaeus classification system

1749:Buffon species shared ancestors

1794-1796: Erasmus Darwin more complex forms develop from less complex forms

1809: Lamarck environmental change leads to use or disuse

1859: Charles Darwin published On the Origin of the Species

1866:Mendel publishes his pea plant research

Theories of Geologic Change Set the Stage for Darwin’s Theory

George Cuvier presented the idea that species could become extinct.

Cuvier observed that within each layer, or stratum, of rocks laid specific type of fossils Traces of organisms that existed in the past

Cuvier proposed the geologic change theory of Catastrophism: Natural disasters have occurred throughout

the Earth’s history causing species to become extinct.

Theories of Geologic Change Set the Stage for Darwin’s Theory

James Hutton proposed the theory of gradualism Slow changes over time

Charles Lyell developed the theory of gradualism into something greater called uniformitarianism Geologic processes that shape the Earth are

uniform throughout time. This theory greatly influenced the work of

Charles Darwin.

Theories of Geologic Change Set the Stage for Darwin’s Theory

Uniformitarianism is the prevailing theory of geologic change.

Reflection (1) Examine early ideas about

evolution. (2) Identify three geological

theories that influenced scientific debate over evolution.

Chapter 10: Evolution

Section 10.2 Darwin’s observations

Objectives 1. Students will be able to describe how

Darwin arrived at his idea about species variation

2. Students will be able to recognize how Darwin’s discoveries supported Lyell’s ancient Earth Theory

Key Concept Darwin’s voyage provided insight on

evolution.

Darwin Observed Differences Among

Island Species Darwin, during 1831, set off on a five year

expedition on the HMS Beagle along the coast of South America and the Pacific Islands

On his travels, he was surprised by the variation of traits among species Variation: difference in physical traits of an

individual from other individuals in the group to which it belongs Interspecific Intraspecific

Darwin Observed Differences Among

Island Species Variation is a difference in a physical trait.

Galápagos tortoises that live in areas with tall plants have long necks and legs.

Galápagos finches that live in areas with hard-shelled nuts have strong beaks.

Darwin Observed Differences Among

Island Species An adaptation is a feature that allows an

organism to better survive in its environment. Species are able to adapt to their environment. Adaptations can lead to genetic change in a

population.

Darwin Observed Differences Among

Island Species

Darwin Observed Fossil and Geologic Evidence Supporting an Ancient

Earth Darwin found fossils of extinct animals that resemble modern animals.

Darwin found fossil shells high up in the Andes mountains.

Darwin Observed Fossil and Geologic Evidence Supporting an Ancient

Earth He saw land move

from underwater to above sea level due to an earthquake.

Darwin extended his observations to the evolution of organisms.

Reflection (1) Describe how Darwin arrived

at his idea about species variation.

(2) Recognize how Darwin’s discoveries supported Lyell’s ancient-Earth theory.

Homework PN Section 10.3 V# 10 Vocabulary due Friday Web Quest due Wednesday