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BLBiology Chapter 20
Beaver local 20
| Question | Answer |
|---|---|
| this measures how a crowded population is | population density |
| the spatial distribution of individuals within a population | dispertion |
| the number of births occuring in a period of time | birth rate |
| the number of deaths in one period of time | mortality rate or death rate |
| how long and average individual is expected to live | life expectancy |
| the distribution of individuals among different ages in a population | age structure |
| the curves that show a likelihood of survival at different ages throughout the lifetime of an organism that are shown on the graphs of mrtality rates. | survivorship curves |
| the amount by which a populations size changes in a given time | growth rate |
| the movement of individuals into a population | imigration |
| the movement of individuals out of the population | emigration |
| this describes a a popultaions that grow rapidly after only a few generations; J-shaped curve | exponential model |
| the faster the population gets, the faster it grows | exponential growth |
| the factor that restrains the growth of a population (not enough food; too much water) | limiting factor |
| this builds on the exponential model but accounts for the influence of limiting factors; S-shaped curve | logistic model |
| the number of individuals the environment can support over a long period of time | carrying capacity |
| when a population size is at its carrying capactiy , the birth rate equals its death rate and growth stops | logistic growth |
| factors that reduce the population by the same proportion, regardless the population size (weather, disasters, fires) | density independant factors |
| factors include rescource limitations and are triggered by increasing population density; the higher the population, the more organisms that are affected (food, territory, nest site) | density dependant factors |
| some population changes can be clearly linked to this | environmental changes |
| this man thought that each species was the cause of the other cycle | Elton |
| mating with relatives | inbreeding |
| during this time, humans lived in small nomadicgroups and obtained food by hunting animals and gathering roots, berries, buts shellfish, and friuts. the human population also grew very slowly. | hunter-gatherer lifestyle |
| this category includes all the worlds modern, industrialized countries such as the US, Japan, Germany, France, The United Kingdom, Australia, Canada and Russia. | developed countries |
| these countries are poorer than the more developed countries and their populations grow much faster. they include countries in Central America, South America and Africa. | developing countries |
| growth rate depends on these four criteria | birth, death, emigration, immigration |
| movement INTO a population | Immigration |
| movement OUT of a population (exiting) | Emmigration |
| These types of countrie includes only 20% of the world's population, yet uses 75% of all of the fossil fuels. | Developed Countries |
Created by:
kjones0722
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