Evolution = change/time Change of what? Inherited characteristics two types Microevolution – refers to change in the gene pool of a population Macroevolution – refers to speciation

Species Concept What is a species? Definition = a group of organisms that are capable of mating with one another in nature to produce fertile, viable (living), offspring

Population Genetics Def: study of changes in the genetic composition of populations What is a population? Def: organisms of the same species living together in the same area/environment NOTE: If organisms live in the same region, they experience same environmental pressures from natural selection!

Peppered Moth Peppered Moth Flies at night and rests on trunks of trees during the day. In 1850, most moths had light colored wings (95%), while some (5%) had dark wings. By 1900, the situation was reversed. What happened? Industrial Revolution – In 1850, tree trunks were covered with a light colored lichen. Light winged moths were camouflaged against the lichen protected them from being eaten by birds. The industrial revolution produced large amounts of soot in central England which covered the trees killing the lichens. Light colored moths resting on dark tree trunks became easy prey. In this new environment, the dark months were more “fit”. As a result, the frequency of the dark colored allele increased as the allele for light colored wings decreased proportionally.

Bacteria & Antibiotic Resistance

How does a species develop? Species develop from other species (ancestor) through variation over time! Variation = differences within a species Arise due to mutation, errors in DNA replication, meiosis, etc.

Does variation alone lead to a new species? No  Isolation! When groups separate they change from one another due to different environmental pressures! What happens when 2 best friends go away to different colleges?

Classification King Phillip Came Over For Great Spaghetti We classify based on a Hierarchical System! Big, general  Small, specific King Phillip Came Over For Great Spaghetti Kingdom Phylum Class Order Family Genus Species

Monera was split into two: archaebacteria and eubacteria Kingdoms of Life Until recently scientists recognized 5 kingdoms: Monera, Protista, Fungi, Plantae, & Animalia Monera was split into two: archaebacteria and eubacteria Now scientists use a six kingdom model: Eubacteria Archaebacteria Protista Fungi Plantae Animalia

Example! Human Classification Kingdom Phylum Class Order Family Genus Species Animalia  Chordata  Mammalia  Primate  Hominidae  Homo  Sapien

Binomial Nomenclature Carolus Linnaeus - Taxonomy Scientific Name vs. Common Name Always written in italics First word is capitalized = genus Second word is lowercase = species Example: White Pine Pinus strobus Dog Canus familaris

History of Evolutionary Theory Jean Baptiste Lamarck Theory of use & disuse Individual organisms change in response to their environment and pass this acquired trait to their offspring. 1744-1829

History of Evolutionary Theory Charles Darwin Early to Mid 1800’s Age 22 left England aboard the HMS Beagle Galapagos Islands, South America, Africa, and Australia

Darwin’s Theory 1859 “On Origin of the Species” Theory of Natural Selection survival and reproduction of organisms that are best suited to their environment

Theory of Natural Selection Main Points Populations tend to grow & overpopulate Resource competition  resources are limited Inheritable Variation exists among populations that makes some individuals more “fit” than others. Those individuals with variation that allows them to survive better will reproduce more often. Their genes & traits are passed onto offspring, causing these genes & traits to increase in proportion in the population.

Evidence for Evolution Fossil Record Comparative Anatomy Molecular Biology Biogeography Embryology

Fossil Record Remains of plants or animals that were once living Used to: reveal the existence of species that came before & are now extinct (Life has changed over time!) Develop relationships Rate of Evolutionary Change Incomplete Why?

Comparative Anatomy Study of different structures used to develop relationships Homologous, Analogous, Vestigial

Molecular Biology Biogeography Study differences in DNA & amino acid sequences Those organisms most closely related have the most similarities. Biogeography Movement of continents  continental drift Trace species back to splits in populations due to continental drift

Embryology Study of similarities during embryo development

What can we conclude from all of this evidence? Descent with Modification! New life forms appeared to be modifications of fossil forms found in similar geographic areas. Implies that modern life forms are descendents of older life forms that have changed slowly over time. Q: What made them change?

Patterns of Evolution Coevolution Change or Evolution of 1 species affects the evolution of another. Ex: Predator Prey (arms race) Convergent Evolution Occurs when environmental pressures act similarly to unrelated species. Example: whale & shark Divergent Evolution 2 or more related species become increasingly different Related species are introduced into different environments. Natural selection states why life forms change. Patterns of evolution indicate examples of how life forms change.

Divergent Evolution Adaptive Radiation Rapid increase in # of species