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19 Cards in this Set
- Front
- Back
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Reproductive table (fertility schedule) |
age specific summary of reproductive rates in a population
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Life history traits |
Traits that influence an organism’sschedule of reproduction and survival |
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- Life history traits are _____-____. - Life history traits are ____________ ________. |
- Life history traits are trade-offs. - Life history traits are evolutionaryoutcomes. |
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what are the 3 basic variables of life history traits? |
1) When reproduction begins (age at first reproduction) 2) How often an organism reproduces 3) How many offspring are produced during a reproductive event |
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Semelparity |
organism undergoes single reproductiveevent during lifetime |
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Iteroparity |
repeated reproductive events throughoutlifetime |
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what are the 3 key points of exponential population growth? |
1. The size of a population growingexponentially increases at a constant rate (r). 2. Population accumulates moreindividuals per unit time when the population is large. 3. Populations with higher per capitarates of increase (r) grow more quickly. |
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Dorealpopulationsever grow exponentially? |
Yes...but only for so long. -species introduced to new environment -population rebounding from catastrophe |
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Why canpopulations not grow exponentially forever? |
- resource limitation |
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Carrying capacity (K) |
the maximum population size that a particular environment can sustain. :crowding and resource limitation can have profoundeffects on population growth rate |
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Logistic model of population growth |
incorporates the carrying capacity (K)thereby modifying the per capita rate of increase based upon population size |
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what are the 3 key points of logistic growth? |
1. When N is small compared to K, the percapita rate of increase isclose to the maximum. 2. When N is large and resources arelimited, then the per capita rate of increase is small. 3. When N equals K, population stopsgrowing. |
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What happens if N exceeds K? |
- Population decline |
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Dorealpopulationsreal population show logistic growth? |
Yes, but there may be lag time. |
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Density-independent |
random events such as floods, drought,hurricanes, volcanic eruptions, wildfire and human factors : typically abiotic factors |
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what are the 5 density-dependent factors? |
•Competition •Predation •Disease and parasites •Toxic wastes (e.g.ammonia or ethanol poisoning) •Intrinsic physiological factors |
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Whatare the top five limitations to human population size on regionalscale? |
1 – Availability of potable drinkingwater 2 – Food availability: farmland, cropyield, diet (vegetarian vs. carnivore) 3 - Fuel: heat, cooling, transportation, etc. 4 – Depletion of other natural andnonrenewable resources: fossil fuels, metals, timber 5 – Environmental degradation/waste |
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Ecological footprint |
summarizes the aggregate land and water necessary to produce all resource consumed andabsorb all wastes generated. |
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Avg. ecological footprint of humans = |
Sum of all ecologically productive land/ Totalpopulation size |
