Descent with ModificationChapter 22

A Darwinian View of Life-

1. challenged---a young Earth inhabited by unchanging species

Objective

• Describe a typical sequence of events of fossilization.

• What is the main mistake usually made in movies about the earliest Earth history?

History of Biological Diversity

• Scientific Inquiry: led to the theory of evolution by natural selection.

• Diversity : concepts of genetics-phylogeny

• Energy: organisms used in metabolism from 1st cell until today.

• Homeostasis: populations and communities might develop adaptation due to long-term disruptions.

• Change: natural selection results in long-term change, or evolution, of populations to produce new species.

• 429-Hutton, Malthus, Lamarck, Lyell, Darwin, Wallace-theory, The Origin of Species-1859, Mendell-1865.

Fossilization- Categories

• Trace fossils-indirect evidence left by • Molds and casts- impression of an

organism• Replacement- remains are replace by

minerals• Petrified or permineralized empty pore

spaces are filled in by minerals.• Amber- preserved tree sap traps organism• Original material- mummification/ freezing

Lamarck-Acquired Characteristics

• Concept of use and disuse, idea that those parts of the body used extensively to cope with the environment become larger and stronger; while those not used deteriorate.

• The inheritance of acquired characteristics to pass on to the offspring.

Darwin’s focus on Adaptation

• Origin of Species developed two main points: the occurrence of evolution and natural selection as its mechanism.

• Natural hierarchy of Linnaean scheme:

kingdom>phylum>class>order>family>

genus>species.

Darwin’s main ideas

• Natural selection is differential success in reproduction.

• Occurs through an interaction between the environment and the variability inherent among the individual organisms making up a population.

• The product is the adaptation of organisms to their environment.

Homologies

• Homologous structures

• Vestigial organs

• Embryological homologies

• Molecular homologies

• Homologies and the tree of life

Homework

• Read Chapter 22---pp. 429---443

• Complete questions #1—16.

• Due Wednesday—material for fossilization and play-doh; questions to share with class. Class will evaluate the quality of the fossil by responding to your questions on Friday.