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Human hands manipulate tools, whale and dolphin fins are adapted for swimming and bird wings are adapted from flying. One example is the pentadactyl limb which exists in a variety of species – mammals, birds, amphibians and reptiles all share a similar arrangement of bones in their appendages based on a five-digit limb. Selective breeding has shown that artificial selection can cause evolution – race horses, for example, have been bred for speed and are lighter, taller and quicker – these changes in traits and characteristics are examples of evolution.Īdaptive radiation is when organisms diversify from an ancestral species into many new ones – these species may have features that are similar in structure despite being used in different ways – these are homologous structures. We can see this by dating the fossils to find out when each sample was from. This content is collectively referred to as Markers, and consist of markers (marker icons), marker areas, and marker poly-lines. download them ahead of time so that they can be sent or saved to the student computers.

The fossil record shows that the features of organisms have changed over time. Title: Evidence of Evolution Homologous Structures.

and indirect evidence like footprints, tooth marks. For IB Biology, there are three types of evidence for evolution you need to know: fossils, selective breeding and homologous structures.įossils are preserved remains or traces of organisms from the past – they include direct evidence like bones, teeth, shells, leaves etc.