Chapter 18 Flashcards
Evolution
The change in organisms throughout
earth’s history. “descent with modification”
Aristotle (384-322 b.c.)
- fixed ideal species
- scala naturae
Judeo-Christian Bible
- creation & young earth
Linnaeus (1707-1778)
- Orderly, nested classification system
- Binomial naming
Georges Cuvier (1769-1832)
- fossils are a record of change over time caused by catastrophic
events - Connected fossil structures with likely habitats
- rock strata mark relative ages
- species changed because of local extinctions
James Hutton (1726-1797)
- Geologist
- slow, continuous processes → geological features
- Gradualism
- Not a particularly good communicator
Charles Lyell (1797-1875)
- Father of Modern Geology
- uniformitarianism expanded Hutton’s ideas:
– same geologic processes in past as today
– same rate as today - thus earth is extremely old!
- Lyell’s popular Principles of Geology (1830) was
read by Darwin - Lyell & Darwin were colleagues and communicated
often
Erasmus Darwin
- Physician and natural philosopher
- “natural philosophy” on evolution
- wrote ideas that “forms minute” slowly
acquired complexity over time - “natural philosophy” on evolution
- wrote ideas that “forms minute ” slowly
acquired complexity over time
Lamarck (1744-1829)
- linked evolution to adaptation
–extinct species have been replaced by descendants with
new features
»these adaptations helped them survive in environment - first to propose a mechanism for evolution:
–“use & disuse” “use it or lose it”
–“inheritance of acquired characteristics”
–but, it’s wrong!
Ship Darwin Travelled on
HMS Beagle 1831-1836
Darwin studied local ___
Geology
* saw evidence for Lyell’s uniformitarianism
– maybe earth was millions yrs. old!
What Theory did Darwin Develop?
Evolution Theory
* essay written in 1844, but not published
* in 1858, Alfred Wallace sent a letter to Darwin with same ideas
* both works presented publicly in 1858
What was Darwin’s book called?
Origin of Species –1859
What are the two main ideas of Darwin’s Theory?
- Descent with modification
- Natural Selection
Natural Selection is …
the mechanism for evolution
First observation of Natural Selection is:
Heritable variation exists in most species
Second observation of Natural Selection is:
All species produce more offspring than
the environment can support. Many, many
offspring die before maturity!
First inference of Natural Selection is:
There is unequal reproductive success among
individuals
Second inference of Natural Selection is:
Those heritable, favorable traits (adaptations)
accumulate over vast time, matching the species to its
environment and ultimately leading to new species!
What are the six things not explained in Darwins Theory?
- Origin of life.
- How variation arises.
- How inheritance works.
- Why variation still exists.
- “Sudden” changes in fossil record.
- Source of totally “new” characters.
What are the 5 pieces of evidence that supports Darwin’s Theory?
- Direct Observation
- The Fossil Record
- Homology
- Convergence
- Biogeography
Fossil Record
– Many extinct species
–Transition of adaptive form over time
Homology
forms related by common ancestry
Homologous structures
- structures derived from a common ancestor (but may be
modified for different functions)
Vestigial structures
remnants of ancestral (homologous) structures with no present
adaptive function
Biogeography
distribution of species
Scientific Theory
A broad, well-supported,
explanation with rich predictive value
Morphological species
smallest set of organisms that look alike
Ecological species
- a set of organisms adapted to a specific
set of resources
Phylogenetic species
- smallest distinct set of organisms that share a
common ancestor
