Transcript SHOW-4-2005
How do plants affect the climate? How do plants affect our climate? 1) Plants purify & replenish our air & water (e.g. recycling CO2, O2 & soil/water nutrients) 2) Earth’s temperatures are influenced by plants due to absorption of solar radiation (photosynthesis). 3) Plants increase humidity by absorbing water that is way below ground level and releasing it (by transpiration) to the atmosphere. How do plants affect our climate? 4) Plants reduce flooding and desertification (erosion). 5) Plants influence microclimates (climates in a small area) by cooling, shading, etc. How do plants affect our climate? 6) Plants can emit volatile organic molecules. …affects Precipitation patterns 4) Plants influence the microclimate (climate of small area) How do plants affect our climate? 7) Fires Discussion Question #1: Which biomes are the most popular with people? Why? Average number of plant species: Biome: Tropical Rainforest 3200 Savanna 1000 Chaparral 2300 Desert 1100 Temperate Grassland 1400 Temperate Deciduous Forests 1900 Temperate Evergreen Forests 1600 Taiga 800 Tundra 400 July, 2005 60oN 30oN Equator 30oS Rainforest Desert !Kung of Kalahari Desert Sherenti of Amazon Forest Average number of plant species: Biome: Tropical Rainforest 3200 Savanna 1000 Chaparral 2300 Desert 1100 Temperate Grassland 1400 Temperate Deciduous Forests 1900 Temperate Evergreen Forests 1600 Taiga 800 Tundra 400 July, 2005 What is the source of all this biodiversity? Discussion Question #2: What basic assumption (or philosophy or attitude) is at the core of scientific research? Two Important Questions: “ Did life on earth always look the same as it does now? ” “ What generated all the diversity of life we currently see on earth? ” 3 Basic Explanations for Earth’s Biodiversity: No Evolution (Creationism) Microevolution = relatively small changes over time...that’s all (Intelligent Design) Macroevolution = speciation (Charles Darwin et al. ) Charles Darwin Theory of Natural Selection Resources that organisms compete for: • Energy • Nutrients • Water • Proper Temperature • Space to live • Reproduction (a mate) • Safety Ecological Niche: “how an organism attains and utilizes the resources of the environment” OR “The job, or profession, of an organism” A brief description of Natural Selection: 1) Organisms within a population contain numerous natural variations for most characteristics (Morphological, Biochemical, Behavioral) 2) This variation is genetic (heritable) Fuchsia Holly Tomato Potato 3) Individuals within any population will produce more offspring than can survive on the resources available to them. The offspring will compete with each other, and with other species. Darwin and his wife had 10 children (3 died) 4) Offspring that have genetic variations that are more favorable in a certain environment will survive and reproduce more than those that have less favorable variations. The genetic makeup of the population changes (evolves)…... Microevolution (and eventually Macroevolution) occurs. 5) All of this variation is random. Also, changes in the environment are chaotic. So, natural selection yields exquisite adaptations that are quite independent of any ‘design’ process. 3 relevant examples We can see microevolution taking place: 1) The emergence of new strains of Influenza viruses every winter. 2) Evolution of new strains of HIV (AIDS) and Hepatitis viruses. 3) The advent of antibiotic-resistant strains of bacteria (like for tuberculosis). 4) Insects and weedy-plant species that have evolved the ability to resist chemical treatments designed to kill them. Artificial Selection Age of the Earth…. Gideon Society says earth was created in 4004 BC... Radioactivity dating says its 4.5 billion years old.… If we can develop different kinds of animals and crops in just a few thousand years, isn’t it hard to believe that nothing would change over millions of years?