Lenore van Vliet - 2988631
21. How evolution works
21.1 THE DARWINIAN REVOLUTION CHALLENGED TRADITIONAL VIEWS OF A YOUNG
EARTH INHABITED BY UNCHANGING SPECIES
Endless forms most beautiful
Shared features illustrate the unity of life, since all organisms share characteristics, Darwin’s theory
illustrated 3 key points:
1. Organisms are well suited for life in their environments
2. The many shared characteristics of life
3. The rich diversity of life
Darwin eventually concluded that life evolves over time!
Evolution = descent with modification
Or also known as change in the genetic composition of a population from generation to generation.
This can be related to two ways we can look at evolution:
Pattern --> data from many different disciplines
Process --> the mechanisms that cause the observed pattern of change = representing the
natural causes of the natural phenomena we observe.
The power of evolution as a unifying theory is its ability to explain and connect a vast array of
observations about the living world.
--> This theory continues to be tested by examining whether or not it can account for new
observations and experimental results.
Scala naturae and classification of species
- Aristotle => recognized certain affinities among organisms and concluded that life-forms
could be arranged on a ladder of increasing complexity later known as the Scala naturae.
- Linnaeus => developed a two part/binomial system for naming species using a nested
classification system, but he did not ascribe the resemblances among species.
- Cuvier => observed that from one layer of stone to the next species disappeared and
appeared. Coming to the conclusion that extinctions are common because each boundary
between strata represents a sudden catastrophic event.
- Hutton => proposed that earth’s geologic features could be explained by gradual
mechanisms.
- Lyell => Used Hutton’s thinking to state that the same geologic mechanisms are operating
today as in the past and at the same rate.
- Lamarck => proposed that life evolves as environments change
Ideas about change over time
Fossils (= the remains or traces of organisms from the past) contain a lot of evolutionary data that
Darwin could use for his theory of evolution through natural selection, agreeing that if geologic
change results from slow continuous processes rather than sudden events, then earth must be much
older than the widely accepted age of a few thousand years.
Lamarck’s hypothesis of evolution
The incorrect mechanism Lamarck proposed is what he is most well-known for: He compared living
species with fossil forms and explained his findings using two principles widely accepted during his
21. How evolution works
21.1 THE DARWINIAN REVOLUTION CHALLENGED TRADITIONAL VIEWS OF A YOUNG
EARTH INHABITED BY UNCHANGING SPECIES
Endless forms most beautiful
Shared features illustrate the unity of life, since all organisms share characteristics, Darwin’s theory
illustrated 3 key points:
1. Organisms are well suited for life in their environments
2. The many shared characteristics of life
3. The rich diversity of life
Darwin eventually concluded that life evolves over time!
Evolution = descent with modification
Or also known as change in the genetic composition of a population from generation to generation.
This can be related to two ways we can look at evolution:
Pattern --> data from many different disciplines
Process --> the mechanisms that cause the observed pattern of change = representing the
natural causes of the natural phenomena we observe.
The power of evolution as a unifying theory is its ability to explain and connect a vast array of
observations about the living world.
--> This theory continues to be tested by examining whether or not it can account for new
observations and experimental results.
Scala naturae and classification of species
- Aristotle => recognized certain affinities among organisms and concluded that life-forms
could be arranged on a ladder of increasing complexity later known as the Scala naturae.
- Linnaeus => developed a two part/binomial system for naming species using a nested
classification system, but he did not ascribe the resemblances among species.
- Cuvier => observed that from one layer of stone to the next species disappeared and
appeared. Coming to the conclusion that extinctions are common because each boundary
between strata represents a sudden catastrophic event.
- Hutton => proposed that earth’s geologic features could be explained by gradual
mechanisms.
- Lyell => Used Hutton’s thinking to state that the same geologic mechanisms are operating
today as in the past and at the same rate.
- Lamarck => proposed that life evolves as environments change
Ideas about change over time
Fossils (= the remains or traces of organisms from the past) contain a lot of evolutionary data that
Darwin could use for his theory of evolution through natural selection, agreeing that if geologic
change results from slow continuous processes rather than sudden events, then earth must be much
older than the widely accepted age of a few thousand years.
Lamarck’s hypothesis of evolution
The incorrect mechanism Lamarck proposed is what he is most well-known for: He compared living
species with fossil forms and explained his findings using two principles widely accepted during his
