Presentation on theme: "Aim: How do we know that evolution happened ?"— Presentation transcript:
1Aim: How do we know that evolution happened ? Figure 17-5 Geologic Time ScaleAim: How do we know that evolution happened ?Section 17-1(millions of years ago)EraPeriodTime(millions of years ago)EraPeriodTime(millions of years ago)EraPeriodTimePermianCarboniferousDevonianSilurianOrdovicianCambrian290 – 245363–290410–363440–410505–440544–505QuarternaryTertiaryCretaceousJurassicTriassic1.8–present65–1.8145–65208–145245–208Vendian650–544Geologic Time ScaleGo to Section:
2If we could follow the fossils of a particular organism up through the layers of the Earth we would have a clear picture of how organisms changed over timeThat does not happen. Finding fossils is like looking for a needle in a haystack. When it happens it is a dramatic event.
3body size over millions of years General trend in equidbody size over millionsof yearsWhile such trends as toe reduction and increase in size are real over time, the rate of change varied among different branches of the equid evolutionary bushHorse species did not always come into being by gradual transformation (anagenesis) of their ancestors; instead, sometimes new species split off from ancestors (cladogenesis) and then co-existed with those ancestors for some time. Described are about 30 genera of horses during 55 million years of evolution. Notice the extensive branching patterns.
4The cladogram graphically represents a evolutionary process Phylogenetic tree of the evolutionary relatedness of organismsa branching diagrammatic tree used in cladistic classification to illustrate phylogenetic relationshipsDo worksheetExplain the differences of the organisms above and below the blackened square.
5Anatomical comparisons indicate the similarities in bone structure suggests a common ancestor
6Comparative Embryology Similarity of embryos during development suggests a common ancestor.Cytology studies, all cells have similar organelles that carry out the same functions.What are these embryos?
7Comparative Embryology Similarity of embryos during development suggests a common ancestor.Cytology studies, all cells have similar organelles that carry out the same functions.
8Aligned DNA fragment and first chromosome banding patterns for man (Homo sapiens), chimpanzee (Pan troglodytes), gorilla (Gorilla gorilla), and orangutan (Pongo pygmaeus).Genetic Similarities. A fragment of aligned DNA sequences that codes for a protein common to each primate species and the chromosome banding patterns for the first chromosomes are depicted in figure 1. Changes in the DNA sequences are double underlined. For the chromosomes, sold indicates similar sequences, hatching, a possible shift in the banding patterns as compared to humans. Changed patterns are stippled. How do the results of your serological tests compare to the depicted chromosome banding patterns and DNA sequences?WHAT SIMILARITIES DO YOU SEE?
9This cladogram shows that.. ………Humans share a common ancestor with other primates, we did not evolve from them
10Prepare a refute to this situation Someone tells you that they are teaching that humans evolved from monkeys.
11Aim: What paths did evolution follow? DIVERGENT EVOLUTION "One ancestral stock evolves into two species, which continue to evolve and become less and less alike over time."The ancestral mammal probably existed about 190 million years ago. It was around at the time of the dinosaurs, but with the extinction of the dinoasurs, the mammals were able to undergo extensive adaptive radiation to fill a wide range of ecological niches.
12PARALLEL EVOLUTION "In PARALLEL EVOLUTION two related species arise from a common ancestor. The two species then evolve in much the same way over time, probably in response to similar environmental selection pressures."In this example, both the wooly mammoth, which occupied parts of North America, and the elephant, still found in Asia and Africa are presumed to have evolved from a common ancestor. Their geographical isolation and environmental selection pressures caused further evolution of the species, but each, in its own location, occupies(d) a similar niche.
13"CONVERGENT EVOLUTION occurs when two or more groups that are not closely related come to resemble each other more and more as time passes. This is usually the result of occupation of similar habitats and the adoption of similar environmental roles.."
14Punctuated equilibrium This type of diagram reflects the theory that evolution has not occurred at a constant rate, rather it has occurred in short bursts with long periods of stability between. This theory explains the absence of the infinite range of intermediate fossils in branches of evolution such as the vertebrates.
15Started on Land and moved to the Sea Evolution of the WhaleStarted on Land and moved to the Sea(whale evolution video)
16What happened to the Dinosaurs? What factors affect whether a species survives or not survive?