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Enviro. 6
| Question | Answer |
|---|---|
| Population Distribution | How individuals are distributed with respect to one another. Either: Random Uniform Clumped |
| Density Dependent factors | the size of the population will influence an individual’s probability of survival. Density-dependent factors include: For terrestrial plants: water and soil nutrients. For animals: food, water, and nesting sites. |
| Density Independent Factors | the size of the population has no effect on the individual’s probability of survival. Density-independent factors include: Hurricanes, tornados, floods, fires, volcanic eruptions, environmental temperatures. |
| Growth Rate | the number of offspring an individual can produce in a given time period, minus the deaths of the individual or offspring during the same period. |
| Intrinsic Growth Rate | under ideal conditions, with unlimited resources, the maximum potential for growth (denoted as r) for a population |
| The Exponential Growth Model | the intrinsic growth rate for a population (r), and current number of reproducing individuals (N0), That is, we can use the exponential growth model to estimate a population’s future size (Nt) after a period of time (t) has passed: Nt = N0ert |
| Logistic Growth | when a population whose growth is initially exponential, but slows as the population approaches the carrying capacity. |
| Carrying Capacity | is the limit of how large a population can be sustained by the limiting resources, especially food. (K in equation) |
| K-selected Species | the population of a species that grows slowly until it reaches the carrying capacity. |
| r-selected species | the population of a species that grows quickly, and is often followed by overshoots and die-offs. |
| Species Interactions | Competition Predation Mutualism Commensalism |
| Competitive exclusion principle | two species competing for the same limiting resources cannot coexist. This can lead to resource partitioning. |
| Predation | the use of one species as a resource by another species. |
| True Predators | kill their prey |
| Herbivores | consume plants as prey |
| Parasites | live on or in the organism they consume. If they cause disease, they are pathogens. |
| Parasitoids | lay eggs inside other organisms |
| Mutualism | A type of interspecific interaction where both species benefit. |
| Commensalism | a type of relationship in which one species benefits but the other is neither harmed nor helped. |
| Symbiotic relationships | two species live in close association. Commensalism, mutualism, and parasitism are all examples of symbiotic relationships. |
| Keystone species | : a species that plays a role in its community that is far more important than its relative abundance might suggest; they are in small numbers |
| Primary succession | occurs on surfaces that are initially devoid of soil. |
| Secondary succession | occurs in areas that have been disturbed but have not lost their soil. |
| Aquatic succession | ex: a pond eventually turning into soil |
| Factors that determine species richness | Latitude:species richness declines. Time:older habitats show more variety of species. Habitat size and distance:size of the habitat and distance from the colonizing species affects the number and types of species. |