CHAPTER 22 notes

CHAPTER 22 notes - CHAPTER 22 DESCENT WITH MODIFICATION: A...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
CHAPTER 22  DESCENT WITH MODIFICATION: A DARWINIAN VIEW OF LIFE Section One:  The historical context for evolutionary theory Darwin made two points in  The Origin of Species : 1.      Today’s organisms descended from ancestral species. 2. Natural selection provided a mechanism for evolutionary change in populations. Natural Selection: A population of organisms can change over the generations if individuals having certain  heritable traits leave more offspring than other individual. Evolutionary Adaptation: A prevalence of inherited characteristics that enhance organisms survival and  reproduction in specific environments.   Ideas that influenced Darwin (see figure 22.2 and know the terms in parenthesis) 1.   Carolus Linnaeus a Swedish botanist binomial nomenclature:  Giving organisms a two word name always written:  Genus species  or  Genus species developed taxonomy:  a system for naming species and grouping species into a hierarchy of  increasingly complex categories. Kingdom, Phylum, Class, Order, Family, Genus, Species General                                            Specific Less Similar                                      More Similar Distantly Related                                Closely Related 2. Paleontology:  the study of fossils Fossils: the relics or impressions of organisms from the past, mineralized in sedimentary  rocks Sedimentary rocks form when mud and sand settle to the bottom of seas, lakes, and marshes New layers of sediment cover older ones, creating layers of rock called strata. Fossils within layers show that a succession of organisms have populated Earth throughout  time. What do fossils show us? 1. Law of Superposition: Since older strata are lower in the fossil layers, fossils of  organisms found lower are older than those found closer to the surface.  Deeper  fossils are more dissimilar to modern life.  2. From stratum to stratum, new species appear and others disappear.  (extinction)
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
3. Gradualism
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 03/28/2011 for the course BILD 1 taught by Professor Chen during the Winter '11 term at UC Riverside.

Page1 / 5

CHAPTER 22 notes - CHAPTER 22 DESCENT WITH MODIFICATION: A...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online