Evidence for Evolution by Natural Selection 2006-2007

Vocabulary Analogous Convergent evolution Embryo Homologous Vestigial

What are the lines of evidence that support Darwin’s ideas?… 10 20 30 40 50 60 70 80 90 100 110 120 Lamprey Frog Bird Dog Macaque Human 32 8 45 67 125 Fossil Record

Evidence of Evolution Darwin argued that life on earth has been evolving for millions of years. 1. Artificial Selection 2. The Fossil Record 3. Geographical location 4. Anatomical evidence 5. Similarities in Early Development 6. DNA and protein similarities (newer evidence)

1)Artificial selection What are the lines of evidence that support Darwin’s ideas? Terminal bud Lateral buds Brussels sprouts Cabbage Flower cluster Leaves Cauliflower Flower and stems Broccoli Wild mustard Kohlrabi Stem Kale 1)Artificial selection Artificial selection Hidden variation can be exposed through selection!

Selective breeding the raw genetic material (variation) is hidden there

What are the lines of evidence that support Darwin’s ideas? 2) Fossil record Millions of years ago 50 100 150 200 250 300 350 400 450 500 550 60 55 45 40 35 30 25 20 15 10 5 Equus Hyracotherium Mesohippus Merychippus Nannippus Body size (kg) sedimentary rock sequence: older fossls on bottom, younger fossls on top

The Fossil Record

Evidence for Evolution – The Fossil Record Darwin and His Theory Evidence for Evolution – The Fossil Record 4/25/2017 G. Podgorski, Biol. 1010

The Fossil Record Showed that: There have been countless species that have lived on earth but no longer live on earth today Layers of rocks with fossils demonstrated that thousands, or even millions of years were needed to create this Species have changed in appearance and complexity

The fossil record The giant sloth

Evolution of birds Archaeopteryx lived about 150 mya links reptiles & birds The avian nature of the brain and inner ear of Archaeopteryx (Alonso et al. 2004) - Archaeopteryx, the earliest known flying bird from the Late Jurassic period, exhibits many shared primitive characters with more basal coelurosaurian dinosaurs (the clade including all theropods more bird-like than Allosaurus), such as teeth, a long bony tail and pinnate feathers. However, Archaeopteryx possessed asymmetrical flight feathers on its wings and tail, together with a wing feather arrangement shared with modern birds. This suggests some degree of powered flight capability but, until now, little was understood about the extent to which its brain and special senses were adapted for flight. Alonso et al. (2004) investigated this problem by computed tomography scanning and three-dimensional reconstruction of the braincase of the London specimen of Archaeopteryx. A reconstruction of the braincase and endocasts of the brain and inner ear suggest that Archaeopteryx closely resembled modern birds in the dominance of the sense of vision and in the possession of expanded auditory and spatial sensory perception in the ear. Alonso et al. (2004) concluded that Archaeopteryx had acquired the derived neurological and structural adaptations necessary for flight. An enlarged forebrain suggests that it had also developed enhanced somatosensory integration with these special senses demanded by a lifestyle involving flying ability. Smithsonian Museum, Washington, DC

Evolution of land animals 2006 Fossil Discovery of Early Tetrapod “Tiktaalik” “missing link” from sea to land animals from swimming (0 legs) to walking (4 legs)

3. Geographic Distribution of Living Species Animals that are related to each other showed ‘descent with modification’ based on their environment (even though probably closely related, looked different because different environment Animals that were not related to each other looked similar if they were from similar environments.

Geographic Distribution of Living Species Example: Based on what they look like: Which two animals do you think are more closely related to one another? Desert Fox Koala Dingo

Geographic Distribution of Living Species Believed to not be closely related to each other even though they look more alike. Evolutionists say they look alike because they live in the same kind of environment so over time they adapted in similar ways Desert Fox Dingo

Analogous structures Dissimilar anatomy doing a similar function 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? Dissimilar anatomy doing a similar function

What is this evidence of? Convergent evolution What is this evidence of? These animals look very similar but does that mean they have a recent common ancestor? marsupial mammals Biogeographical evidence No! Convergent / parallel evolution similar environments & niches lead to natural selection of similar traits placental mammals

What are the lines of evidence that support Darwin’s ideas? 4) 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!

Homologous Structures Arms, wings, legs, and flippers all have very similar bones Similar in anatomy doing different potentially different functions Darwin believed this was evidence that all species were original descended from one common ancestor.

Homologous structures spines leaves succulent leaves tendrils needles colored leaves

Why would whales have pelvis & leg bones if they were always sea creatures? These are remnants of structures that were functional in ancestral species Vestigial organs Humans Appendix Coccyx Wisdom Teeth Darwin’s Tubercle (ear) Palmaris Longus Goose bumps Pseudogenes – L-gulonolactone oxidase 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

Vestigial Organs Humans Appendix Coccyx Wisdom Teeth Darwin’s Tubercle (ear) Palmaris Longus Goose bumps

5. Similarities in Early Development Looking at the embryonic development of organisms Darwin noticed some similarities that other scientists also noticed.

Evidence for Evolution - Comparative Embryology Darwin and His Theory 4/25/2017 Evidence for Evolution - Comparative Embryology Why do embryos of different animals pass through a similar developmental stage? G. Podgorski, Biol. 1010

Comparative hemoglobin structure 6. Putting it all together with DNA evidence Why compare DNA & proteins across species? The sequence in DNA & proteins is a molecular record of evolutionary relationships. 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 Why compare these genes? compare common genes cytochrome C (respiration) hemoglobin (gas exchange) Number of amino acid differences between hemoglobin (146 aa) of vertebrate species and that of humans

Building “family” trees Closely related species (branches) share same line of descent until their divergence from a common ancestor