BIOL 1103 1st Edition Lecture 2ECOLOGY: Population Growth and Regulation1) Population: consists of all the members of a particular species that live within an ecosystem, 2) Ecosystem: a defined geographical area 3) Populations make up a community: a group of interacting populations 4) Biosphere: large ecosystem that comprises all of Earth’s livable surface 5) Ecology: the study of the interrelationships of organisms with each other and with the nonliving environment  Change in Population Size1) Birth2) Death3) Net Migration IF births exceed deaths, exponential growth occurs: this is when a very large number is added to the population during each succeeding generation: Usually explained by Carrying capacity and by using a J-Graph. - Biotic Potential (max rate at which a population can grow): and its 5 influences:1. The age at which the organism first reproduces 2. The frequency of reproduction3. The average number of offspring produced each time 4. The length of the organism’s reproductive life span 5. The death rate of individuals- Population Size: interaction between biotic potential and environmental resistance- Exponential growth usually happens under unusual conditions - Exponential growth occurs temporarily when environmental resistance is reduced These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- Invasive species are organisms with a high biotic potential that are introduced into ecosystems where they did not evolve and where they encounter little environmental resistance: EX: family buys a snake as a pet, and then releases the snake into the wild. The snake is now called an INVASIVE SPECIES- Density-independent factors limit populations regardless of their density - Ex: Dinosaurs going extinct - Density-dependent factors become more effective as population density increases - Ex: animals hunting for food during high breeding times. - Competition: interaction between individuals who attempt to use the same limited resource, which limits population size in a density-dependent manner - Humans: Natural selection has favored those who are able to bear and take care of their offspring. Community Interactions- The FOUR (4) major community interactions are 1. Competition2. Predation3. Parasitism4. Mutualism- Ecological Niche: all physical environmental conditions necessary for survival and reproduction of a given species- No two species ever occupy exactly the same ecological niche within the same natural communityEcological Niche influence on Competition?- Competition: when two organisms attempt to use the same, limited resources- Predators: eat OTHER living things- Predators are usually < than their PreyCoevolution: Ex: has given lions very sharp teeth and claws or tearing prey Camouflage Mimicry: members of one species having evolved to resemble another