Darwin noticed that the finches on different islands were slightly different: Different beaks Different diets
Galapagos Tortoises Darwin noticed that the giant tortoises on different islands had different characteristic. How would Lamarck explain these differences? Galapagos tortoise closeup!
Why are the animals different? Each island has slightly different weather: lower islands are barren and dry, higher islands are wetter So, different islands have different vegetation, different habitat.
Tortoises with longer necks could reach the higher vegetation in drier areas, so they survived and reproduced, passing their long-necked genes to their offspring. Tortoises in wetter areas had plenty to eat and didn’t need long necks to survive and reproduce. Galapagos tortoise
Natural Selection: Individuals that have traits better suited to their environment are more likely to survive and reproduce. “survival of the fittest” http://www.uri.edu/cels/nrs/paton/spring_peeper/ sppe_camoflage2.JPG
Darwin’s steps of natural selection : Variation –inherited variation in every population Overproduction – populations produce more offspring than can possibly survive (leads to competition for resources!) Selection – individuals with favorable traits leave more offspring Adaptation – over time, favorable traits become more common in a population
Evolution: A change in an inherited characteristic of a population over time. Individuals DO NOT evolve!
Adaptation: An Inherited trait present in a population because it helps individuals survive AND reproduce in a given environment. Individuals may have adaptations, but they DO NOT CREATE adaptations through use. (That’s Loser Lamarck!)
Macroevolution (forming new species) is a slowww process! It takes many generations to develop adaptations!!!
Microevolution is a change in the gene frequencies of a population. Can happen quickly Ex: antibiotic resistant bacterial colonies
Coevolution Two species develop adaptations in response to one another Disea nivea Orchid and fly
Darwin’s Artificial Selection When breeding livestock, humans choose the parents with traits they want in the offspring. Ex: dogs, cows, horses, pigeons
Resistance The ability of an organism to tolerate a particular chemical designed to kill it. Ex: pesticide resistance
Terrestrial Biomes Tropical - low latitudes, warm, water varies –rain forests - lots of rain –savannas - less rain, long dry season –deserts - little rain, lower biodiversity –http://www.bbc.co.uk/learningzone/clips/imag es-of-a-tropical-biome/3205.htmlhttp://www.bbc.co.uk/learningzone/clips/imag es-of-a-tropical-biome/3205.html
Temperate - mid-latitudes, temp. varies grasslands - moderate water, cooler temps than savannas forests - plenty of rain, mild climate deserts - little rain, wide temp. range
High Latitude –taiga - forests in cold, wet climates –tundra - little rain, mostly frozen http://www.bing.com/images/search?q=taiga&form=QBIR&qs=n&sk=&sc=8- 5#focal=21f2731d29856171ea9611a8694e4371&furl=http%3A%2F%2Fwww.johndrew.com%2FAlaska%2520Image s%2FTundra%2520Approaching%2520the%2520Alaska%2520Range1.jpg
Aquatic Ecosystems Freshwater - lakes, ponds, rivers Wetlands - mix of land/water Estuary - fresh meets salt water Marine - salty water
Biosphere: the part of the world in which life can exist