Species Change Over Time

CH 6 Objectives Identify early ideas and observations on evolution Explain how Darwin developed his theory of natural selection Identify Darwin’s 4 principles of natural selection Describe how new species can form from previous species

Essential Questions and Understandings What is evolution and who contributed to the modern theory of evolution? Compare and Contrast Artificial and Natural Selection What are Darwin’s 4 principles and how do they lead to evolution? What is speciation? How can isolation of a group of individuals lead to a new species?

Evolution is defined as change over time It is the result of changes in the genetic material that are passed from generation to generation Organisms use adaptations to have a better chance of surviving and reproducing

History Lamarck was on of the first scientists to suggest the idea of change over the lifetime of an organism (Giraffes Necks) Darwin studied plant and animal species on the Galapagos Islands (178 islands) He noticed that species were different from island to island Looked at adaptations to certain environments Looked at finches and their feeding behaviors

Artificial Selection When people (breeders) produce new varieties of animals over time Select a certain desired trait Breed two animals displaying that trait The result is offspring displaying the trait

Darwin proposed the same thing was happening naturally in the animal and plant world He based his ideas on 4 principles: Overproduction: When a species produces more offspring than can live in the environment Variation: mutations that naturally occur in the genetic material Adaptation: any inherited trait that gives an organisms an advantage to survive Selection: if a trait helps an organism survive to reproduce, the trait has been “selected” Natural Selection

Speciation The evolution of new species from an existing organism Can occur when the environment changes dramatically such as a volcanic eruption New species can also occur when the environment changes gradually

Formation of New Species due to Isolation Example from a population of Cichlids (fish) Water level is low, one species lives in a lake Level rises filling shoreline, population spreads throughout the lake Level falls, isolating the fish from each other New species development that are more successful in their environment

Isolation Can Lead to New Species Scientist believe that Isolation is essential to speciation Isolation can occur due to geographic changes such as mountains building up Cases caused by isolation have led to the great level of biodiversity on Earth

CH 7 Classification of Living Things

CH 7 Objectives Explain why scientists classify living things Describe evidence scientist use to classify organisms Explain how scientific names are determined and give examples Use the 7 levels of classification to identify an organism Describe organisms found in each of the current 6 kingdom system of classification Describe the 3 domains Describe how dichotomous keys can be used to identify organisms Utilize a dichotomous key to identify common household objects

Essential Questions and Understanding Understand how scientist study biological relationships to classify living organisms How has our classification system changed over time? Describe how we give organisms scientific names and give and example. Use a dichotomous key to classify organisms correctly Identify characteristics of organisms found in the 6 kingdoms

1600’s: organisms were classified based on appearance and behavior PROBLEM: Can be deceiving, not universal (i.e. they could not ALL agree on a system for naming organisms) 1700’s: 2 Kingdoms (Plant and Animal) Linnaeus set a standard 2 name system for each animal (Genus species) Linnaeus developed a system for naming species and organizing them into groups 1866: 3 Kingdom Sytem (plant, animal, protista) 20th Century: Started using DNA and genes to classify related species 1925: 2 Kingdoms (Prokaryota & Eukaryota) 1938: 4 Kingdoms (Monera, Protoctista, Plantae, Animalia) 1969: 5 Kingdom System (Monera, Protista, Plantae, Fungi, Animalia) 1977: Current 6 Kingdom System 2000’s:???? 7 Kingdoms???? No Kingdoms??? Domains??

Classification Classification is the process of arranging organisms into groups based on similarities Taxonomy: science of naming and classifying organisms To classify organisms scientists use similarities and differences among species A classification system (such as one found in a field guide can help you identify unfamiliar organisms A taxon is a group of organisms that share certain traits based on shared ancestors. Not All organisms that look alike are closely related

Binomial Nomenclature Each organism has a 2 part name Scientific name Written in Latin and Greek Genus species Genus: a group of species with similar characteristics Species: the specific name for the organism (contains the least number of organisms) EX) Homo sapiens (human), Aubrieta gracilis (flower), Chameleo gracilis (chameleon), Mammillaria gracilis (cactus)

7 Levels of Classification to Name a Species Each level is more specific than the last Kings Play Chess On Fat Green Stools Kingdom Phylum Class Order Family Genus Species

Dichotomous Keys Asks a series of questions that can be answered in only two ways. Each answer leads to another question until you identify the organism

KEY TO THE CRITTERS ON BEBONK 1. Has 1 hair………………………………………………..2 Has 2 hairs………………………………………………4 2. Has a belly button…………………………………BIP Has no belly button………………………………3 3. Has 2 legs………………………………………………GLIP Has 4 legs……………………………………………FOOP 4. Has arms…………………………………………….GLOP Has no arms……………………………………….NOP

Multicellular Live on water and land Obtain energy from sunlight Have a nucleus, cell wall, chloroplast EX) grass, trees, moss Kingdom Plantae

Kingdom Animalia Multicellular Live on water and land Obtain energy by eating food Have a nucleus, no cell wall, no chloroplast Have the ability to move EX) human, elephant dog, fish bugs

Kingdom Protista Most are unicellular Nucleus Have the ability to move Some eat like animals Some get energy from sunlight EX) Sea weed, Kelp, Euglena

Takes nutrients from environment Rooted in one place Have cell walls Kingdom Fungi Takes nutrients from environment Rooted in one place Have cell walls Act as decomposers EX) Mushroom, yeast, molds

Live in extreme environments-high heat, high salt, high sulfer Kingdom Archaea No Nuclei Live in extreme environments-high heat, high salt, high sulfer EX) Methanococcoides burtonii

Reproduce by dividing in two Can move EX) E. Coli Kingdom Bacteria Unicellular No Nuclei Reproduce by dividing in two Can move EX) E. Coli