Evolution in Process 15.3 pp. 289-292
Evolution is a continuous process that is always going on, just really slowly (needs lots of time)
Evolution in Process 15.3 pp. 289-292
Homologous structure = similar feature found in many different species• Comes from some common
ancestor• Examples: different beaks
for different birds• Forelimbs (arms) in high order
animals
• Similar species,different job
Evolution in Process 15.3 pp. 289-292
Analogous structure = feature that does the same job but is very different in structure• Wings on birds (arms) vs.
wings on insects (just wings)
• Webbed feet on ducks vs. fins on fish
• Different species, same job
Evolution in Process 15.3 pp. 289-292
Coevolution = 2 different species in close relationship that evolve together• Predator – prey : gazelle
get faster to escape, cheetah get faster to catch the gazelle
• Plant – pollinator: hummingbirds and the flowers they feed on
Evolution in Process 15.3 pp. 289-292
Convergent evolution = different species evolve features to do a similar job in a similar environment• The conditions they live in
are similar so they need to do similar things to survive
• Sharks – dolphins : these have converged
• Different species, same job
What does it mean to converge?
Related to analogous structure.
Evolution in Process 15.3 pp. 289-292
Divergent evolution = very similar species evolve different features to do different jobs• Different habitats so they
evolve different ways to survive
• Sea snakes – desert snakes• Penguins -- ducks• Artificial selection: dog
breeding, cattle breeding (these are done by humans, not nature)
• Similar species, different job
Related to homologous structure.
Evolution in Process 15.3 pp. 289-292
Examples of divergent evolution.
Where on the graph to species diverge?