Ecology :. The scientific study of interactions among organisms and between organisms and their environment. Biotic Factors. Living organisms Dead organisms Organisms ’ waste. Abiotic Factors. Nonliving things in an ecosystem
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Ecology: The scientific study of interactions among organisms and between organisms and their environment.
Biotic Factors • Living organisms • Dead organisms • Organisms’ waste
Abiotic Factors • Nonliving things in an ecosystem • Ex.: Rocks, water, temperature, sunlight, oxygen, sand, climate
Biodiversity The number of different species in an area
Climate • average weather conditions in an area over a long period of time • determines kinds of species present
Abiotic factors affect biodiversity • Temperature: very high or very low temp. limits biodiversity • Water: amount limits biodiversity
High biodiversity resists damage better! • Ecosystem damage can come from • natural disasters (fire, flood, volcanic eruptions) • human impact
Human activities can lead to Habitat Destruction
Habitat • The place where an organism lives
Competition • Species sharing limited resources must compete
Invasive Exotic Species • Species not native to a particular region. • Can outcompete or prey on native species, threatening their survival Zebra mussels in Great Lakes
Levels of Organization • Species • Population • Community • Ecosystem • Biome • Biosphere
Biome: a region with specific communities and climate (temp. and precipitation).
Evolution: • Process by which species change over time. • Descent with Modification
Charles Darwin • 1809-1882 • English Naturalist • HMS Beagle 1831-1836 • Sailed around world gathering specimens and fossils and observing geology
Darwin found unique animals • Marine iguana • Many other species that live no other place on earth.
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 niveaOrchid 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/images-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%2520Images%2FTundra%2520Approaching%2520the%2520Alaska%2520Range1.jpg