Chapter 22

Early Ideas About Evolution  Carolus Linnaeus  Botanist  Classification of organisms (Taxonomy)  Still used today  Binomial nomenclature  Developed the species idea  Species-organisms so related that can interbreed

Early Ideas About Evolution  Erasmus Darwin  Darwin’s grandfather  All living things from a common ancestor  Gave rise to his grandson’s theory

Early Ideas About Evolution  Georges Cuvier  Species can’t change, but the can go extinct  Fossils – preserved remains of living things  Catastrophism  Natural disasters shape Earth  Cause species to become extinct

Early Ideas About Evolution  Hutton and Geological Change  Gradualism - geological forces shape the earth  Layers of rock form very slowly  These layers are shaped by natural forces  Due to the slow nature of the forces, he concluded Earth is very old

Early Ideas About Evolution  Lyell’s Principles of Geology  Uniformitarianism  To understand the past, you have to look in the “now”  Earth process  Volcanoes  Earthquakes  Erosion

Early Ideas About Evolution  Lamarck’s Evolution Hypotheses  Living things have changed over time— and that all species were descended from other species.  Organisms change to adapt to their environment

Early Ideas About Evolution  Tendency Toward Perfection  All organisms strive to be complex and perfect  This leads to constant change  This change is a response to the environment and a desire to be perfect

Early Ideas About Evolution  Use and Disuse  Organisms could alter the size or shape of an organ - Use it or lose it  If you don’t use the structure it will go away  If you use it continually, it will get larger

Early Ideas About Evolution  Inheritance of Acquired Traits  Animals can change their body  If they do they can pass on the new trait  Ex. – Giraffes and long necks

Early Ideas About Evolution  Evaluating Lamarck’s Hypotheses  Many of Lamarck’s ideas were incorrect

Darwin’s Theory  Voyage of the Beagle  The Beagle was British Naval ship  Charles Darwin  The father of evolution

Darwin’s Theory  As a member of H.M.S. Beagle  Darwin collected animal and plant specimens  These specimens were later used to create the theory of evolution

Darwin’s Theory  Variation – difference in physical traits  He found 68 different species of beetles in one day in a Brazilian forest!  Found variations when traveling from place to place

Darwin’s Theory  Patterns of Diversity  Types of animals in similar places  Ways that animals reproduce  Ways that animals survive  Adaptation – feature that makes an organism better suited to its environment

Darwin’s Theory  Living Organisms and Fossils  Darwin found Glyptodon  Rationalized that extinct animals looked much like existing animals

Darwin’s Theory  The Galapagos Islands  A group of islands northwest of South America  Darwin spent a lot of time collecting there:  Iguanas  Birds  Tortoises

Darwin’s Theory  The Journey Home  Darwin observed that the characteristics of many animals and plants varied noticeably among the different islands of the Galapagos.  According to this hypothesis, these separate species would have evolved from an original South American ancestor species after becoming isolated from one another.

Theory of Natural Selection  Inherited Variation and Artificial Selection  Variation within domesticated species species  Breeders select characteristics they want  Pigeons  Heritable  For variations to be bred for characteristic must be able to be passed on

Theory of Natural Selection  Survival of the Fittest – individuals that can survive and reproduce  This is also called Natural Selection

Theory of Natural Selection  The reason for a structure or feature is because of adaptations  Ultimately, natural selection results in either an organism changing traits, OR it dies

Theory of Natural Selection  Alfred Wallace  Developed a nearly identical  Sent his manuscript to Darwin  Wanted to publish the same findings Darwin had

Theory of Natural Selection  Publication  On the Origin of Species  Darwin was nervous about publishing  It challenged every fundamental scientific belief

Theory of Natural Selection  Four main principles of Natural Selection  Variation  Overproduction  Adaptation  Descent with modification

Theory of Natural Selection  Variation  Exist in all populations  Result from differences in genetic make up  Parents  Mutations

Theory of Natural Selection  Population Growth  Malthus  A population can not grow forever  Food  Space

Theory of Natural Selection  Overproduction  Produce more offspring  More chance for survival  Increase competition

Theory of Natural Selection  Adaptation  An inherited trait that improves the organism’s chance of survival  Successful adaptations make animals better suited to their environment  Adaptations can be anatomical, structural, characteristics, physiological, or functions

Theory of Natural Selection  Descent with modification  These adaptations will lead to different species over time  Different:  Structures  Niches  Habitats

Theory of Natural Selection  Natural Selection Summary:  Organisms with certain heritable traits survive and reproduce at higher rates because of those beneficial traits  Over time, natural selection increase the match between organisms and their environments  When organisms moves to a new environment or the environment changes, natural selection may result in new adaptations and ultimately new species

Evidence of Evolution  Soapberry bug  Success dependent on length of mouthpart  Most successful when length of mouthpart matches depth of food  Researches found in populations with food closer to fruit surface, organisms had short mouthparts

Evidence of Evolution  Drug resistant bacteria  Staphlococcus aureus  1 in 3 harbor this bacteria on skin or nasal passages with no ill effects  MRSA – methicillin resistant stapholococcus aureus

Evidence of Evolution  Similarities in Embryology  Crab and barnacle larvae  Vertebrate embryos look very similar early in development  Evidence for common descent

Evidence of Evolution

 Homologous Body Structures  Structures that come from the same embryonic tissues  Homologous structures – bat wing and human hand  Analogous structures – bird wing and insect wing

Evidence of Evolution  Vestigial organs – organs with little to no function  Natural selection has caused the organ to shrink or “disappear”

Evidence of Evolution  Convergent Evolution – evolution towards similar characteristics in unrelated species  Analogous structures  Bird and bat wings

Evidence of Evolution  Divergent Evolution – closely related species in different directions  Results from adapting to different environments  Kit and Red Fox

Evidence of Evolution  Geographic Distribution  Species move from place to place  Ancestral species to islands  Certain traits may be beneficial when moving  Ex. Finches  Biogeography  Study of the distribution of organisms around world