| A | B |
|---|
| what is population density | pop. per.sq.mile |
| how to calculate pop.density | area divided by number |
| what is pop.density for 121 fish in a lake 7 meters square | 17.2 |
| pop. densityfor 15,000 bacteria living in 3 sq. millimeters | 5,000 |
| pop. density for 17 crickets per sq. meter in your backyard. total pop.of 138crickets. what is the area? | 8 |
| pop. density of beaver in Sptb. is 6 per.sq.mile. the total area is 132 sq.miles. what is total population of beavers | 22 |
| population growth | total # of individuals added - the total lost/unit of time. can be neg. or pos. |
| in chesnee 475 babies born, 25 new people move to town,25 died,25 move all in one month. what is the growth rate? | 450 |
| total peguin pop. was 1200 beginning of year and 1600 by end of year. what was pop. growth rate | 400 per sq. yd |
| during the next year 159 chicks were born, 25 died and 50 adults died.what would the growth rate be | 75 |
| 3 factors that affect pop. size | number of births, number of deaths, number that enter and leave pop. |
| define when individuals move out of town | Emigration |
| individuals move into an area | Immigration |
| what factors must population have available to them to be able to grow | space, food, protected from disease and predators |
| under what conditions does exponential growth occur | individuals in pop. reproduce at constant rate. it increase slowly over a period of time |
| exponential growth can slow or stoop because | death rate increase |
| what cause growth rate to slow or stop | when birthrate decreases, or death rate increases, or both occur at same rate |
| logistic growth occurs when | the population growht slows or stops following a period of exponential growth |
| maxium number of individual a population can support is called K or | carrying capacity |
| characteristics of population | geographic distribution, density, and growth rate |
| density-independent limiting factors include: | competition, predation, parasitism, disease |
| density independent factors include | unusual weather, natural diseasters, seasonal cycles, human activities |
| human poopulation grow by | good algriculture and industry made life easier and safer for humans. reliable food supply, goods shiped from around the globe |
| mono culture | large fields are planted with a single crop every year |
| green revolution | use of modern algriculture techniques to increase yields of food crops. |
| threats of biodiversity | hunting species to extinction,toxic compounds into food.and foreign species in new inviroments |
| biologica magnification | increasing concentration of harmful substances in organisms at higher trophic levels in a food chain |
| invasive species | plants and animals migrated to a place where they are not native |
