copyright cmassengale Evolution Change through Time copyright cmassengale
What You Should Know How To Explain at End of Unit… copyright cmassengale
Evolution and Biodiversity 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. (CHANGE IN POPULATION THROUGH TIME) copyright cmassengale
copyright cmassengale 2. Explain how evolution is demonstrated by evidence from the fossil record, comparative anatomy (embryos), genetics, molecular biology, and examples of natural selection. copyright cmassengale
copyright cmassengale 3. Describe 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. copyright cmassengale
copyright cmassengale 4. Explain how evolution through natural selection can result in changes in biodiversity through the increase or decrease of genetic diversity within a population. copyright cmassengale
History of Evolutionary Thought
Early Ideas On Earth’s Organisms Aristotle believed species were fixed creations arranged by their complexity
Early Ideas On Earth’s Organisms Linnaeus – 1st to group similar organisms and assign them Latin names Two word name (Genus species) Known as Binomial nomenclature copyright cmassengale
Taxonomy King Phillip Came Over For Good Spaghetti
copyright cmassengale USA Kingdom MA Phylum Taunton Class Bristol-Plymouth Order Room # Family Jennifer Genus Bisch Species copyright cmassengale
Lamarck’s Theory of Evolution Jean-Baptiste Lamarck, 1809 One Of First Scientists To Understand That Change Occurs Over Time Stated that Changes Are Adaptations To Environment acquired in an organism’s lifetime Said acquired changes were passed to offspring (NOT TRUE) copyright cmassengale
Lamarck’s Theory of Evolution Idea called Law of Use and Disuse If a body part were used, it got stronger If body part NOT used, it deteriorated
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Charles Darwin
Voyage of the Beagle Charles Darwin Born Feb. 12, 1809 Joined Crew of HMS Beagle, 1831
Darwin returned 5 years later in 1836 Darwin Left England in 1831 Darwin returned 5 years later in 1836 copyright cmassengale
copyright cmassengale The Galapagos Islands Volcanic islands off the coast of South America Island species varied from mainland species & from island-to-island species Each island had long or short neck tortoises copyright cmassengale
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The Galapagos Islands - Finches Finches on the islands resembled a mainland finch More types of finches appeared on the islands where the available food was different (seeds, nuts, berries, insects…) Finches had different types of beaks adapted to their type of food gathering (speciation)
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Darwin’s Observations & Conclusions The Struggle for Existence copyright cmassengale
copyright cmassengale Definition Evolution is the slow , gradual change in a population of organisms over time copyright cmassengale
Darwin’s Conclusion Production of more individuals than can be supported by the environment leads to a struggle for existence among individuals Only a fraction of offspring survive each generation Survival of the Fittest through Natural Selection
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copyright cmassengale Evidence Supports… Either: EVOLUTION – change over time DESCENT WITH MODIFICTION (We came from a common ancestor, but, have changed through time based on our environment.) copyright cmassengale
Common Descent with Modification Darwin proposed that organisms descended from common ancestors Idea that organisms change with time, diverging from a common form Caused evolution of new species (speciation)
Descent With Modification copyright cmassengale
Evolution By Natural Selection Concepts The Struggle for Existence (compete for food, mates, space, water, etc.) Survival of the Fittest (strongest able to survive and reproduce) Natural Selection Descent with Modification (new species arise from common ancestor replacing less fit species) EVOLUTION copyright cmassengale
Natural Selection Cannot Be Seen Directly It Can Only Be Observed As Changes In A Population Over Many Successive Generations Radiation Fossil Record
Speciation The formation of new species Results from: Genetic Drift Gene Flow Temporal isolation Geographic Isolation (HAPPENS BY ACCIDENT) (MOVEMENT IN OR OUT) (TIMING OFF) (SEPARATED)
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Theory of Evolution Today Evidence copyright cmassengale
Fossil Record Earth is Billions of Years Old Fossils In Different Layers of Rock (sedimentary Rock Strata) Showed Evidence Of Gradual Change Over Time
Similarities in DNA Sequence (molecular evidence) best one!
Analogous & Homologous Body Structures They have separate evolutionary origins, but are superficially similar because they have both experienced natural selection that shaped them to play a key role in flight (lived in similar environment). Analogies are the result of convergent evolution They have traits that are similar because they were inherited from a common ancestor
copyright cmassengale Convergent Evolution Process whereby organisms not closely related independently evolve similar traits as a result of having to adapt to similar environments or ecological niches. Divergent Evolution Process whereby organisms closely related independently evolve different traits as a result of having to adapt to different environments or ecological niches. copyright cmassengale
Homologous Structures
Vestigial Organs Vestigial Organs Appendix In Man Hip bone in whale
copyright cmassengale Embryonic Evidence Embryonic Structures Of Different Species Show Significant Similarities Embryo – early stages of vertebrate development copyright cmassengale
copyright cmassengale Evidence for Evolution - Comparative Embryology Similarities In Embryonic Development copyright cmassengale
copyright cmassengale Modes of Selection Stabilizing Selection – average trait is advantageous Disruptive Selection – both extremes are advantageous Directional Selection – one extreme is advantageous copyright cmassengale