Torrey Pine (OofW)
Eg of relictual distribution - seeds are not very widespread - sign that it will become extinct soon
Genetic change over time
Change in genetic composition of a population across generations
Change in the composition of different types of species over time
Any trace of an organism that lived in the past
Reveals an absolute time scale for evolutionary events; is evidence of organisms without living descendents that existed in the past
Fossilized tree sap
Characteristic of entire population, NOT an individual
Eg of fossils used to test evolution theory
Hypothesis: early land vertebrates evolved from fish, early amphibians evolved from early land vertebrates. Evidence: radiometric data of fossils provides estimates of age.
Its discovery ended the extinction controversy (controversy amongst people who believed that God created all organisms at the SAME time)
Succession (of fossils)
Fossils from one region is similar to extant (= existing today) organisms from that same region. Eg: Aus fossils are more similar to Aus organisms that to Euro organisms
Organisms that have characteristics of both ancestral and modern forms. Eg: wasp ant - transitional form between wasps and ants
Tiktaalikk roseae (eg: common ancestor)
Share a common ancestor with tetrapod. Could be transitional form between fish (has scales and fins, lived in shallow water) and tetrapods (has ribs, has neck, fish don't have neck)
Archaeopteryx (eg: transitional form)
Transitional form between dinosaurs (has teeth, has heavy endoskeleton-cannot fly) and birds (has feathers).
Functionless organ in one species that has important function in other species.
Blind cave salamander (eg: vestigial organs)
Did not need eyes because lived in very dark place, maintaining eyes cost its resources , instead, lose eyes and develop sense of smell and hearing
Human goose bumps (eg: vestigial organs)
Goose bumps are used to make hair stand up. In mammals: used to trap air to keep warm, used to make animal look bigger- intimidating. Not useful in humans since we have very little hair
Similar structure but with different functions, due to inheritance of traits from a common ancestor. Eg: butterfly and dragonfly both have wings coming out of thorax
Structural homology (eg: mammal forelimb)
Mammal forelimbs have same basic structure with different functions. Eg: human arm, cat leg, whale fin, bat wing
Similar structures during development, becomes different when grow into adult.
Developmental homology (eg: vertebrate embryos)
All vertebrate have tail remnants. All have something similar to gill slits of fishes
Similarities among organisms at the molecular level
Molecular homology (eg: genetic code)
Same codons specify same amino acid, in ALL organisms
Evolution of similar features independently in different evolutionary lineages. Often because of different antecedent features or different developmental pathways. Eg: squirrels and flying squirrels
Evolution of pesticide resistance
Resistance mechanisms may often result from single gene changes. Because of strength of selection, RESISTANT GENOTYPES spread rapidly.