I can explain how The fossil record Anatomical
- Slides: 42
I can explain how • The fossil record • Anatomical, embryological, cellular and molecular similarities • Artificial selection can be used as evidence for the evolutionary development of a given species
HS‑LS 4‑ 1. Communicate scientific information that common ancestry and biological evolution are supported by multiple lines of empirical evidence. • Fossil record (transitional species, evidence of past life and environments) • anatomical structures (structural similarities, homologous structures) • appearance of structures in embryological development. ] • similarities in DNA sequences (molecular similarities)
Evidence: the fossil record Remember when we looked at the fossils? • Fossils provide evidence of past life
Transitional species found in fossil record fish –amphibian (Tiktaalik fossil)
Transitional fossils: bird/reptile Archaeopteryx J-park scene: comparing dinosaur fossils to modern day birds
Vestigial legs in dolphins found
Evidence: structural similarities (a. k. a. homologies/homologous structures) 1. Homologies • Evolutionary theory predicts that related organisms will share similarities that are derived from common ancestors. • Similar characteristics due to relatedness are known as homologies. • Homologies can be revealed by comparing the anatomical structures of different living things, studying embryological development in different organisms, cellular similarities and molecular (especially DNA) similarities between organisms.
Spines, flowers, insect –catching traps and pits are all modified ___________? What function do the modified leaves serve for each of the 4 types of plants?
Another example of homology is the forelimb of tetra pods (vertebrates with legs). Humans, cats, whales and bats all have different forelimbs, reflecting their different lifestyles. But those different forelimbs all share the same bone elements - the humorous, the radius, ulna and other bone elements in common.
• Some of the most interesting homologous structures are vestigial structures, structures of little, if any importance to current organisms. Vestigial structures are organs or structures remaining or surviving in a degenerate, or imperfect condition or form. Vestigial pelvis and legs
• Snakes have legged ancestors. Some species of living snakes have hind limb-buds as early embryos but rapidly lose the buds and develop into legless adults. The study of developmental stages of snakes, combined with fossil evidence of snakes with hind limbs, supports the hypothesis that snakes evolved from a limbed ancestor. Photo to the left, the Cretaceous snake Pachyrhachis problematicus clearly had small hindlimbs. The drawing at right shows a reconstruction of the pelvis and hindlimb of Pachyrhachis.
What are some other examples of vestigial structures?
• Figure 2. 1. 1. Vestigial structures of various organisms. From top to bottom: A. A hypocritical ostrich with its wings extended. B. A blind cave salamander look closely for the eyes buried underneath the skin. C. Astyanax mexicanus, the Mexican tetra, a blind cave fish.
Vestigial legs in dolphins found
Vestigial structures in humans?
Charles Darwin listed a number of putative human vestigial features, which he termed rudimentary, in The Descent of Man (1890). These included
Evidence: embryological similarities
Embryological similarities • Darwin saw that embryonic resemblances would be a very strong argument in favor of the genetic connectedness of different animal groups.
• What species is this? ?
Ultimately: the body form of an organism is controlled by its DNA (genes) – stay tuned (Hox genes)
Homologies: at the cellular level • All living things are fundamentally alike. • At the cellular level living things are remarkably similar to each other. These fundamental similarities are most easily explained by evolutionary theory: life shares a common ancestor. What cellular structures are shared by all eukaryotic organisms?
Evidence: homologies at the molecular level • What genetic code is shared by all species?
DNA!! (bonus link)
The molecular level (cont) In fact, the DNA code itself is a homology that links all life on Earth to a common ancestor. • DNA and RNA possess a simple four-base code that provides the recipe for all living things. • In some cases, if we were to transfer genetic material from the cell of one living thing to the cell of another, the recipient would follow the new instructions as if they were its own. • These characteristics of life demonstrate the fundamental sameness of all living things on Earth and serve as the basis of today's efforts at genetic engineering.
GFP traditionally refers to the protein first isolated from a gene found in the jellyfish Aequorea victoria which glows in the dark. • The GFP gene can be transferred to other organisms which will express this same trait.
Glo. Fish, the first genetically modified animal to be sold as a pet
Genomic comparison evidence • Comparative genomics is a field of biological research in which the genome sequences of different species — human, mouse, and a wide variety of other organisms from bacteria to chimpanzees — are compared. • genomic comparisons article • Protein comparison
• By comparing the sequences of genomes of different organisms, researchers can understand what, at the molecular level, distinguishes different life forms from each other. • Comparative genomics also provides a powerful tool for studying evolutionary changes among organisms, helping to identify genes that are conserved or common among species, as well as genes that give each organism its unique characteristics. • Fossil genes? ? • Activity : HHMI- Ice fish (link)
The genetic similarities among organisms
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Evidence: the pattern of organism groupings. • Classifying life based on evolutionary relatedness
Evidence: The direct observation of evolutionary changes in the laboratory and in the wild. • Darwin’s views on the role of environmental factors in the screening of heritable variation was heavily influenced by artificial selection. • Humans have modified a variety of domesticated plants and animals over many generations by selecting individuals with the desired traits as breeding stock.
The domestication of corn (a somewhat corny example) http: //www. hhmi. org/biointeractive/breeding-corn-teosinte
artificial selection- dogs
Want to learn more? ? Here are some great sites to check out!! • Understanding evolution (UC Berkeley) : http: //evolution. berkeley. edu/ • PBS Evolution site: http: //www. pbs. org/wgbh/evolution/ • • The Complete Work of Charles Darwin Online: http: //www. topsite. com/goto/darwin-online. org. uk The American Association for the Advancement of Science: http: //www. aaas. org/news/press_room/evolution/ The National Science Foundation: http: //www. nsf. gov/news/special_reports/darwin/home. jsp Science Daily- current findings in evolutionary biology: http: //www. sciencedaily. com/news/fossils_ruins/evolution/ • Nature: http: //www. nature. com/nature/supplements/insights/evolution/ • Howard Hughes Medical Institute http: //www. hhmi. org/biointeractive/browse? field_bio_format_type%5 B 0%5 D=23448&field_biointeractive_t opics%5 B 1%5 D=23477
I can explain how • the fossil record • anatomical, embryological, cellular and molecular similarities and • artificial selection can be used as evidence for the evolutionary development of a given species
- 17-1 the fossil record
- Fossils evidence of evolution
- Defintion of a fossil
- What is the “fossil record”?
- Section 15-1 review the fossil record
- Skeletal system
- Fossil record
- Darwin viewed the fossil record as
- Specimen record observation
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