Evolution and Natural Selection MCAS Biology Ms. Mahoney

Central Concepts: Evolution is the result of genetic changes that occur in constantly changing environments. Over many generations, changes in the genetic make-up of populations may affect biodiversity through speciation and extinction. 5.1 Explain how evolution is demonstrated by evidence from the fossil record, comparative anatomy, genetics, molecular biology, and examples of natural selection.

Theory of Evolution Developed by Charles Darwin Based on natural selection Evolution: – A change in a species over time Natural selection: – Organisms with traits well suited to an environment are more likely to survive and produce more offspring than organisms without these favorable traits Biodiversity: – Organisms become very different from each other as they evolve and become better suited to their environments

Evidence of Evolution Fossil Record – See older and extinct species – Look at changes in structures over time Adaptations – Structures and behaviors that organisms have evolved in order to survive better in their environments – Natural Selection

Evidence of Evolution Molecular Biology – All living organisms have DNA ATP and RNA and use similar processes (replication, protein synthesis) – DNA of closely related organisms looks very similar ALL evidence show connection to a common ancestor – DNA is the best use to show evolution

Evidence of Evolution Comparative anatomy – bodies of different organisms are compared to see if they are related Homologous structures: body structures on different organisms that are similar Vestigial structures: body structures that may have served a purpose in ancient ancestors but no longer function in current organisms – Example: __________________ All vertebrate embryos look very similar as they develop before birth

Homologous Structure

Central Concepts: Evolution is the result of genetic changes that occur in constantly changing environments. Over many generations, changes in the genetic make-up of populations may affect biodiversity through speciation and extinction. 5. 2Describe species as reproductively distinct groups of organisms. Recognize that species are further classified into a hierarchical taxonomic system (kingdom, phylum, class, order, family, genus, species) based on morphological, behavioral, and molecular similarities. Describe the role that geographic isolation can play in speciation.

Species Share the same DNA Reproduce with each other and create offspring – Offspring must be able to also reproduce Speciation – Development of a new species – Can happen if organisms are separated and DNA changes (through mutations) and organisms can no longer reproduce Called geographic isolation

Taxonomy Kingdom – Animal, Plant, Fungi, Protist, Bacteria Phylum Class Order Family Genus Species – Most specific

Kingdom Phylum Class Order Family Genus Species Animalia Chordata Mammalia Carnivora Felidae Panthera leo

GROUP NAME ORGANISM HUMANCHIMPANZEEHOUSE CATLIONHOUSEFLY KINGDOMAnimalia PHYLUMChordate Arthropoda CLASSMammal Insect ORDERPrimates Carnivora Diptera FAMILYHominidaePongidaeFelidae Muscidae GENUSHomoPanFelis Musca SPECIESsapienstroglodytesdomesticaleodomestica Scientific Name Homo sapiensPantroglodytes Felis domestica Felis leo Musca domestica

Central Concepts: Evolution is the result of genetic changes that occur in constantly changing environments. Over many generations, changes in the genetic make-up of populations may affect biodiversity through speciation and extinction. 5.3Explain how evolution through natural selection can result in changes in biodiversity through the increase or decrease of genetic diversity within a population.

4 Major Points of Evolution 1.Variation exists within the genes of every species *the result of random DNA mutation 2.In a particular environment there certain individuals that are better suited to survive *Due to variation *Will produce more offspring *Natural Selection 3.Over time, traits of surviving organisms tend to spread through that population *Become more common in the population *DNA changes are too great and cause speciation to occur 4. There is clear proof from fossils and many other sources that living species evolved from organisms that are extinct.

Human-induced selection 1)Natural pop’n with variation for insecticide resistance 2)Insecticide appl’n kills all but those with resistance 3)Surviving insects breed new generation of insecticide resistance population