GEOG 1401 EXAM 3.pdf - GEOG 1401 UNIT 15 15.1 Evolution...

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GEOG 1401 UNIT 15 15.1 Evolution Evolution: changes that take place within species over time and also the development of new species from older ones. Natural Selection: the idea that those better adapted to the environment are more likely to reproduce, so the genetic makeup of the next generation is slightly different than the previous one. The change from one generation to the next is likely to be very small, but over many generations, significant changes take place. o Genetic variation means that some members of a species are more likely to survive and reproduce than others. Micro/macro evolution o Micro-evolution: (change within a species) The change from one generation to the next is likely to be very small, but over many generations, significant changes take place o Macro-evolution: (speciation) If members of one species get separated in two different environments, different characteristics will be advantageous and over time, they may evolve into different species. Darwin & Wallace: independently developed the theory of evolution o all species of organisms arise and develop through the natural selection of small, inherited variations that increase the individual's ability to compete, survive, and reproduce. 15.2 Species Range Species Range: the geographic boundary of where it is found
2 o Determined by two main factors: where can the species get to and can it survive there? Dispersal: the ability of species to move into new areas o Barriers stop dispersals o Plant dispersal is slower Adaptation: o A species evolves because it is becoming better adapted to the environment in which it lives. Abiotic factors: part of the physical environment o Climate affects plants and animals o Topography o Soil factors Biotic factors: involve living things o Competition: Interaction where two or more organisms in the same space require the same resource (e.g., food, water, nesting space, and ground space) which is in limiting supply to the individuals seeking it. Competition can occur at the interspecific or intraspecific biotic levels. Competition may also be the result of two different processes: exploitation or interference. o Predation: a predator species eats a prey species. In some cases, the predator species can drive a prey species from a region, thus limiting its range. o Competition and predation sometimes eliminate a species from an area, but often species can co-exist in the relationship. Limiting factor: If one factor dominates the boundaries of the range, then that is called the limiting factor. o Ex: Armadillos are limited by temperature as they expand their range to the north.
3 15.3 Convergent Evolution (none) 15.4 Ecosystems Ecology: the study of organisms and how they interact with the environment Ecosystem: organisms and natural environment in a particular Energy flow: The energy for most ecosystems is sunlight, which plants convert to sugars, another form of energy, in the process of photosynthesis. Plants, therefore, are Producers. Primary consumers

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