Evidences of Evolution PDF

EVIDENCES OF EVOLUTION Prepared by: Ms. Abbey Gail Chem L. Pancho Most Essential Learning Competencies QUARTER 3 (WEEK 4) Explain the evidence of evolution (e.g. fossil record, biogeography, homology, DNA sequences, and embryology) Infer evolutionary relationships among organism using the...

EVIDENCES OF EVOLUTION Prepared by: Ms. Abbey Gail Chem L. Pancho Most Essential Learning Competencies QUARTER 3 (WEEK 4) Explain the evidence of evolution (e.g. fossil record, biogeography, homology, DNA sequences, and embryology) Infer evolutionary relationships among organism using the evidence of evolution. What is Evolution? came from a Latin word evolutio meant the unrolling of a scroll A theory is a well- substantiated Evolution is the process by explanation of an aspect which species adapt over time of the natural world that in response to their changing can incorporate laws, environment. hypotheses and facts. Evidence for Evolution Many genetic, anatomical, physiological, archaeological and geographical discoveries have been made that support the theory of evolution; these include: Fossil records Artificial selection Geographic distribution Homologous structures Molecular homologies Embryology  are the preserved remains and traces of past life. Fossils Dependent on their structure, composition and/or role, fossils can be classified as: Moulds Carbon imprints Trace Casts Petrified Permineralized Index Transitional Living Preserved remains Transitional Fossils Fossilized species that share traits with present day descendants are known as transitional fossils. As they exhibit similarities in form with more than one species, they can be used to determine relatedness and common ancestry. Transitional Fossils A. Archaeopteryx Archaeopteryx was a firm confirmation of the relationship between birds and dinosaurs. It possesses a combination of traits that clearly place it as a transitional form between non-avian dinosaurs and birds. Transitional Fossils A. Archaeopteryx The discovery of the furcula (wishbone), or fused clavicle bone, was a firm confirmation of the relationship between birds and dinosaurs, as they are the only two groups to have this anatomical feature. Transitional Fossils B. Pakicetus It also exhibited characteristics of its anatomy that link it to modern cetaceans, a group made up of whales, porpoises, and dolphins. indicates that the earliest relatives of enormous whales like humpbacks were comparatively small land mammals. Transitional Fossils B. Pakicetus It is linked as a whale relative through its unique inner ear shape. Only whales have such an enhanced region of the ear called an "auditory bulla"-- and Pakicetus has this too. Transitional Fossils C. Tiktaalik roseae A four-legged semi-aquatic fish that indicates the evolutionary history of tetrapods (four-legged, mostly terrestrial organisms). It represents the transition of vertebrate life from water to land. Transitional Fossils C. Tiktaalik it did have fins, the bones inside the fins are homologous to the bones of the human hand and wrist, indicating it may have been able to bear weight. Transitional Fossils D. Pezosiren portelli This species likely represents the transitional form of sea cows (dugong) and manatee (order Sirenia), as it maintained the general body plan of a sea cow, but just without flippers. Transitional Fossils D. Pezosiren portelli Pezosiren had 4 legs it used to walk on land, but it also had heavy ribs that could indicate it lived part time in water, much like a hippopotamus. Artificial Selection Also known as ‘selective breeding’ the identification by humans of desirable traits in plants and animals, and the steps taken in future generations. to enhance and perpetuate those traits Artificial Selection  Artificial Selection Artificial selection of wild mustard plant (Brassica oleracea) leads to evolving of variety of a plant species. Strains are developed to produce distinct desired traits in the plant and are usually named by their breeders (or by creative consumers). Artificial Selection Geographic Distribution/Biogeography The geographic distribution of organisms on Earth follows patterns that are best explained by evolution, in combination with the movement of tectonic plates over geological time. Geographic Distribution/Biogeography Name of Physical or behavioral Geographic differences organism similarities they feed on the originated in South humming bird nectar of tube- America shaped flowers using a long straw- like proboscis to found across humming bird siphon off the temperate regions of hawk-moth sticky fluid while Eurasia hovering in the air Geographic Distribution/Biogeography Name of Physical or Geographic differences organism behavioral similarities in the Americas and are cactus distributed from Canada have big fleshy to Chile. stems full of water, deep roots tropical areas of Africa, and spines instead Madagascar, and the euphorbia of leaves. Americas to warmer, temperate areas of Asia and Europe. Geographic Distribution/Biogeography Name of Physical or Geographic differences organism behavioral similarities Most can be found in puffin Have streamlined Iceland body shape , adapted for life living in nearly all aquatic dolphins underwater environments, including oceans, coastal, estuarine and freshwater Geographic Distribution/Biogeography Name of Physical or Geographic differences organism behavioral similarities sugar glider Have big eyes, a native distribution includes (Petaurus white belly, and a continental Australia and breviceps) thin piece of skin the island of New Guinea stretched between their arms and legs, North American, northern which helps them Eurasia, and in the flying squirrel “glide” and remain temperate and tropical stable when leaping forests of India and other from high places parts of Asia. Geographic Distribution/Biogeography Convergent evolution refers to the evolution in different lineages of structures that are similar or ‘analogous’, but that cannot be attributed to the existence of a common ancestor Geographic Distribution/Biogeography Divergent evolution represents the evolutionary pattern in which species sharing a common ancestry become more distinct due to differential selection pressure which gradually leads to speciation over an evolutionary time period. Geographic Distribution/Biogeography Due to differential selection pressure, species with a common ancestor grow increasingly divergent, eventually leading to speciation. Adaptive radiation, evolution of an animal or plant group into a wide variety of types adapted to specialized modes of life. Geographic Distribution/Biogeography Due to differential selection pressure, species with a common ancestor grow increasingly divergent, eventually leading to speciation. Adaptive radiation, evolution of an animal or plant group into a wide variety of types adapted to specialized modes of life. Geographic Distribution/Biogeography Adaptive radiation, evolution of an animal or plant group into a wide variety of types adapted to specialized modes of life. Ground finch species Geographic Distribution/Biogeography Adaptive radiation, evolution of an animal or plant group into a wide variety of types adapted to specialized modes of life. Tree finch species Comparative Anatomy Comparing the anatomy of present day, transitional and ancestral organisms with each other, gives insight into the similarities and differences between various body structures. Both internal and external form can be observed and associated with function between organisms to identify the degree of evolutionary relatedness. Depending on what is being compared, structures can be referred to as being: Homologous Analogous Vestigial Homologous Structures These structures look different externally, however, actually link two species to a common ancestor. The structures are essentially the same but differ in shape, size etc. Examples include: The pentadactyl Insect limb mouthparts Vertebrate The mollusk hearts foot Homologous Structures The Pentadactyl Limb It consists of the bones Scapula making up the appendages of tetrapod vertebrates and Humerus often refers to the ‘arm’, although can also refer to the ‘leg’ as well. Radius These differences can be Ulna attributed to how the structure has adapted to suit Carpals unique environmental selection Phalanges pressures to aid survival.  Homologous Structures The Pentadactyl Limb 1. Humerus 2. Radius 3. Ulna 4. Carpals 5. Metacarpals 6. Phalanges holding walking swimming flying Homologous Structures Word origins penta = ‘five’ The Pentadactyl Limb dactyl = ‘finger’ Can you spot the bones of the pentadactyl limb? Analogous Structures Analogous structures are similar structures that evolved independently in two living organisms to serve the same purpose. Similarities in shape, size, color, etc. can be attributed to the organisms experiencing similar environmental pressures therefore requiring similar structures to aid survival.  Analogous Structures Name of Body structure with Lineage organism similar function a long straw-like humming bird proboscis to siphon Class Aves off the sticky fluid while hovering in humming bird the air Class Insecta hawk-moth  Analogous Structures Name of Body structure with Lineage organism similar function Class Magnoliopsida, cactus have big fleshy Order Caryophyllales stems full of Family Cactaceae water, deep roots and spines instead Class Magnoliopsida euphorbia of leaves. Order Euphorbiales Family Euphorbiaceae  Analogous Structures Name of Body structure with Lineage organism similar function Have streamlined puffin body shape , Class Aves adapted for life underwater dolphins Class Mammalia  Analogous Structures Name of Body structure with Lineage organism similar function sugar glider Class Mammalia, (Petaurus Have big eyes, a Subclass metatheria breviceps) white belly, and a (marsupial) thin piece of skin flying squirrel (patagium) stretched between Class Mammalia, (Glaucomys their arms and Subclass eutheria volans) legs, (placental).  Analogous Structures Wings of birds, Dorsal fins of fish and mammals, and insects wings of penguins Gliding ‘wings’ of marsupial and placental mammals Vestigial Structures Anatomical structures that are present but no longer functional in modern-day organisms are known as vestigial structures. Their presence indicates functionality in their ancestors, so if two modern-day species have the same vestigial structure, it is evidence for shared ancestry. Vestigial Structures Structure Ancestral function for breaking down tough, uncooked foods, ancient Wisdom teeth human species needed a broader jaw containing extra molars. Coccyx (tailbone) used for balancing their body and locomotion  Vestigial Structures Structure Ancestral function for bearing the weight of individuals superior to the pelvis, stabilizing them, and Whale pelvis allowing them to sit and stand as the legs located inferiorly move. Appendix/Caecum Used to digest tough food like tree bark Vestigial Structures Examples include: Ratite (flightless birds) wings Whale pelvis Wisdom teeth Appendix/Caecum Coccyx (tailbone)  Molecular Homogeny Involves comparing the frequency, presence, absence, sequences of nitrogenous bases, genes, chromosomes, amino acids, proteins and entire genomes. Monkey Mouse Chicken Chicken Lamprey 95% 87% 69% 69% 14% Similarities of human DNA and protein sequences to other animals.  Molecular Homogeny By identifying similarities and differences, sets of conserved genes that determine a taxon’s characteristics can be identified. Monkey Mouse Chicken Chicken Lamprey 95% 87% 69% 69% 14% The less genetic differences between two species when compared with others, the more closely related they are.  Molecular Homogeny A phylogenetic tree, also known as a phylogeny, is a diagram that depicts the lines of evolutionary descent of different species, organisms, or genes from a common ancestor. A Synapomorphy is a character or trait that is shared by two or more taxonomic groups and is derived through evolution from a common ancestral form. An autapomorphy is a distinctive feature, known as a derived trait, that is unique to a given taxon. Molecular Homogeny Comparative Embryology Embryos of vertebrates develop in the same way. Vertebrates are classified as such as they share the following set of characteristics: Notochord - develops into the spinal cord Hollow dorsal nerve cord - develops into the central nervous system: the brain and spine. Comparative Embryology Embryos of vertebrates develop in the same way. Vertebrates are classified as such as they share the following set of characteristics: Pharyngeal pouch/gill slits - develop into gill arches in bony fish and into the jaw and inner ear in terrestrial animals. Post-anal tail - develop into skeletal extension of the posterior end of the body Comparative Embryology Pharyngeal pouch Post-anal tail Chick embryo (LM) Human embryo Comparative Embryology The more recently and thus closely related two species are, the more physically similar their embryos will appear, earlier on in development.  In summary Comparative anatomy Comparison of physical characteristics between living, extinct, transitional, and/or embryonic forms. Structures can be classed as homologous, analogous or vestigial. Molecular homogeny The fossil record Comparison of nitrogenous Provides information about transitional base sequences, genes, forms and comparative anatomy. amino acid sequences, Indicates evolutionary distance and proteins and entire relatedness via fossil dating. genomes.  END OF PRESENTATION