Changes Over Time EVOLUTION
Charles Darwin The Father of Evolution
History Darwin s World (1809-1875) Height of the British colonial period. Beginning of the Industrial Revolution. New Ideas: Taxonomy of Carolus Linnaeus Lyell s Principles of Geology
Carolus Linnaeus (1707 1778) Binomial System of Nomenclature Believed in the Fixity of Species
Father of Geology Charles Lyell
Charles Lyell s view of the process of formation of sedimentary rock
Suggests that sedimentary rock is very old therefore the species that are represented in this rock must also be old. Most fossils are found in sedimentary rock. Older fossils will be found below younger fossils.
Charles Darwin At the age of 22, he joined a 5 year expedition aboard the HMS Beagle to map the coast of South America
The voyage of the Beagle
Charles Darwin s Theory of Evolution: 1. Members of a population have heritable variations. (Inheritance of traits)
2. In a population, more individuals are produced than the environment can support. They compete for food and shelter. (overpopulation- struggle for survival).
3. Some individuals have adaptive characteristics that enable them to survive and reproduce better than other individuals (survival of the fittest).
4. An increasing number of individuals in succeeding generations have these adaptive characteristics (natural selection)
Darwin described his theory in the form of a long essay which he called On the Origin of Species.
Publication of On The Origin of Species in 1859
Charles Darwin At age 50 (1859) At age 65 (1874)
Charles Darwin Before publication After publication
Through his observations made in the Galapagos Islands, Charles Darwin formulated a theory of how species change over time, called natural selection.
Natural selection is governed by the principles of genetics. The change in the frequency of a gene in a given population leads to a change in a population and may result in the emergence of a new species. Natural selection operates on populations over many generations.
Evolution A change in successive generations of organisms, due to random mutation and changes in the organisms surroundings
Evolution takes place through a set of processes that include: mutation, adaptation, natural selection, extinction.
Mutation Genetic mutations and variety produced by sexual reproduction allow for diversity within a given population. Many factors can cause a change in a gene over time.
Mutations are important in how populations change over time because they result in genetic changes to the gene pool. Mutation
Mutations are inheritable changes because a mutation is a change in the DNA code
Mutation- a change in the DNA A mutation may result in a: 1. favorable change or adaptation in genetic information that improves a species ability to exist in its environment
Mutation- a change in the DNA 2. an unfavorable change that does not improve a species ability to exist in its environment.
Mutation- a change in the DNA 3. in a change in the genetic information that neither harms nor helps the species.
Adaptation Adaptations are structures, functions, or behaviors that enable a species to survive.
Adaptation Depending on the rate of adaptation, the rate of reproduction, and the environmental factors present, structural adaptations may take millions of years to develop.
Natural Selection the survival and reproduction of the individuals in a population that exhibit the traits that best enable them to survive in their environment. The Survival of the Fittest
Natural Selection Populations produce more offspring than the environment can support.
Natural Selection The unequal ability of individuals to survive and reproduce leads to the gradual change in a population, generation after generation over many generations.
Organisms with certain genetic variations will be favored to survive and pass their variations on to the next generation. Natural Selection
These five canine species evolved from a common ancestor through natural selection Jackal African wild dog Fox Wolf Coyote Thousands to millions of years of natural selection Ancestral canine
When humans choose organisms with specific characteristics as breeding stock, they are performing the role of the environment This is called artificial selection Example of artificial selection in plants: five vegetables derived from wild mustard
Artificial Selection in Animals: Dog Breeding German shepherd Yorkshire terrier English springer spaniel Mini-dachshund Golden retriever Hundreds to thousands of years of breeding (artificial selection) Ancestral dog
The evolution of insecticide resistance is an example of natural selection in action Chromosome with gene conferring resistance to insecticide Additional applications of the same insecticide will be less effective, and the frequency of resistant insects in the population will grow Survivor Insecticide application
Fossil Record Although there is not a complete record of ancient life for the past 3.5 billion years, a great deal of modern knowledge about the history of life comes from the fossil record.
The study of fossils provides strong evidence for evolution. Hominid skulls Petrified Trees
Ammonite casts Fossilized organic matter in a leaf
Scorpion in amber Ice Man
Distribution of species Most marsupials live in Australia This supports the theory of continental drift.
Distribution of species
Geographic isolation can lead to speciation
Organisms that can breed and produce FERTILE offspring. Species
Adaptive Radiation where species all deriving from a common ancestor have over time successfully adapted to their environment via natural selection
Homologous Structures Body parts in different organisms that have similar bones and similar arrangements of muscles, blood vessels, and nerves and undergo similar embryological development, but do not necessarily serve the same function; e.g., the flipper of a whale and the forelimb of a horse.
Homologous Structures Human Cat Whale Bat