Notes over Evidence of Evolution Agenda: Bell Ringer Notes over Evidence of Evolution Anatomical Structures Evidence Lab Objective: I can explain how anatomical structures were used as evidence for evolution.

Evidence Supporting Evolution 2006 Fossil Discovery of Early Tetrapod “Tiktaalik” “missing link” from sea to land animals Evidence Supporting Evolution

Pre-Darwinian Theories _______________________________________________________________ Earliest references are from the Greeks; even Darwin’s grandfather believed in the common ancestry of all organisms Jean Baptiste Lamarck (French zoologist) believed species were derived from preexisting species

Darwin’s Theories Summed in 2 theories 1. _______________: new forms appearing in the fossil record are actually the modified descendents of older species Inferred that ALL species had descended from one or a few original types of life Accounted for biogeography: similar organisms arise in the same geographic location Modern kangaroos evolved from now-extinct ancestor

2. _____________________– states how evolution occurs; environment limits the growth of populations by increasing the rate of death or decreasing the rate of reproduction, or both May affect individual organisms in a population in different ways Organisms w/ greater number of favorable traits will leave more offspring Different degrees of successful reproduction is natural selection

Evidence for Evolution Paleontology – fossils show change in a species over time Biogeography – Similar species are found in similar ecosystems around the world Morphology – Comparing structures Homologous structures – ___________________________________________________________________________________________________________________________ ___________________– similar structure develops in organisms that share a common ecosystem but not a common ancestry Biochemical or Molecular - Similarities in gene sequences, proteins, DNA

Fossils _______________________ Paleontology is the study of the fossil record Most organisms do not leave a fossil after death Explains the “missing links” As the organism decomposes the spaces will be filled with the minerals from the silt

Fossil Evidence of Evolution Fossils are the preserved remains of once-living organisms Rock fossils are created when three events occur organism buried in sediment ____________________________________________________ surrounding sediment hardens to form rock

The Archaeopteryx Fossil Forelimb has three functional fingers with grasping claws. Reptilian Features Lacks the reductions and fusions present in other birds. Breastbone is small and lacks a keel. True teeth set in sockets in the jaws. The hind-limb girdle is typical of dinosaurs, although modified. Long, bony tail. Avian Features Vertebrae are almost flat-faced. Impressions of feathers attached to the forelimb. Belly ribs. Incomplete fusion of the lower leg bones. Impressions of feathers attached to the tail. LEFT: Archaeopteryx lithographica Found in 1877 near Blumenberg, Germany

Fossil Evidence of Evolution Fossils document evolutionary transition The oldest known bird fossil is the ___________________ It is intermediate between bird and dinosaur Possesses some ancestral traits and some traits of present day birds ______________________________

How old is that fossil? _____________ Age of fossils based according to their location in strata Age of fossils determined by analyzing the content of radioactive isotopes found in the fossil. Half-life: The length of time required for half of the radioactive elements to change into another stable element. Unaffected by temperature, light, pressure, etc. All radioactive isotopes have a dependable half life. Ex: C14 decays into N14

Relative Dating

Absolute Dating How radioactive “naturally occurring” elements get inside an organism: A.K.A – Radiometric dating

Anatomical Evidence for Evolution Homologous structures: structures with different appearances and functions that all derived from the same body part in a common ancestor _____________________________________________________________________ Different functions, same ancestor structure

Anatomical Evidence for Evolution Analogous structures: __________________________& anatomy Same functions, different ancestor structure

Anatomical Evidence for Evolution Vestigial structures: ________________________, but resemble structures their ancestors possessed Vestigial structures of a whale

Homologous Structures Anatomical evidence Anatomical evidence 1. These structures are called… homologous 2. These structures are evidence for…. common ancestry 3. similar internal structure = similar development 4. different function = different environment & niche 5. close evolutionary r’ship!

Analogous structures Solving a similar problem with a similar solution Convergent evolution Don’t be fooled by their looks! same function different development & anatomy Those fins & tails & sleek bodies are analogous structures! convergent evolution - NOT common ancestor Those fins & tails & sleek bodies are analogous structures! Does this mean they have a recent common ancestor? Solving a similar problem with a similar solution

Comparative hemoglobin structure Molecular Homology The sequence in DNA & proteins is a molecular record of evolutionary relationships. Why compare DNA & proteins across species? 10 20 30 40 50 60 70 80 90 100 110 120 Lamprey Frog Bird Dog Macaque Human 32 8 45 67 125 Comparative hemoglobin structure Molecular Record What are we comparing here? - comparing DNA (base sequence) & proteins (amino acid sequence) What assumption do we make about genes and relatedness?  the more closely related, the more DNA bases & amino acids you have in common have to compare genes for protein the organisms have in common… can’t compare genes for proteins you don’t have Number of amino acid differences between hemoglobin (146 aa) of vertebrate species and that of humans

Vestigial organs These are remnants of structures that were functional in ancestral species Why would whales have pelvis & leg bones if they were always sea creatures? Remains of ancestral structures = mutations can occur without affecting survival & reproduction Evolutionary relationship snakes & whales — remains of pelvis & leg bones of walking ancestors eyes on blind cave fish human tail bone

Patterns of Evolution Divergent Evolution (adaptive radiation) ______________________ Is it a shark or a dolphin??

Divergent vs. Convergent Types of EVOLUTION Divergent vs. Convergent

DIVERGENT EVOLUTION To Diverge means to spread apart. Think of other words that use the same root word. “Dissect, Divide, Divorce” Could two or more different species have shared a common parental species?

DIVERGENT EVOLUTION To Diverge means to spread apart. Think of other words that use the same root word. “Dissect, Divide, Divorce” Could two or more different species have shared a common parental species?

ADAPTIVE RADIATION - In some circumstances, many separate groups will break off from the main population to form their own isolated gene pools. These individual gene pools will undergo their own changes due to Genetic Drift, Mutation and Natural Selection. During these circumstances, many new species may form from one Parental Species. This is known as ADAPTIVE RADIATION

CONVERGENT EVOLUTION To Converge means to bring together. Think of other words that use the same root word. “Congregate, Concert, Connect” Could two or more different species that look similar and have similar traits, be totally unrelated To one another?

During Convergent Evolution Analogous Structures are seen Analogous structures are structures that have very different genetic origin, but they have very similar function. Example Wings are a great adaptation, regardless of whether you are a bird, mammal, insect or dinosaur. Ancestral Insect

Coevolution _____________________________________________________ predator-prey disease & host competitive species mutualism pollinators & flowers

Evolution evidence at the cellular level Domains: Archaea, Bacteria and Eukarya Elements conserved through all: DNA, RNA and many metabolic pathways. Eukaryotes – core features: Cytoskeleton Nucleus Membrane-bound organelles Linear chromosomes Endomembrane system