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Side ASide B
A group of individuals of the same species living within a specified area is a
the number of individuals per unit of area or volume in the habitat is
- Forced by the occurrence of resources, ______ is the most common dispersion ...
- Humans in North America show a ______ distribution pattern.
the maximum rate of increase in numbers by a population is
the factors determining population size
Births, deaths, immigration, and emigration
- When births and deaths are equal, there is
ZPG or ‘zero population growth.’
The ‘intrinsic rate of increase (r) is
the difference between the birth rate and death rate
When limiting factors are absent, population growth is
- exponential (a ‘J-shaped curve’).
Ideally, populations are limited in size by the habitat
‘carrying capacity (K).’
Carrying capacity (K) is determined by
- resource availability and organismal tolerance of habitat conditions.
If population changes are not related to its size, the causative factors are called
- For example, a flood that eliminates a population of rabbits would be a _____-_____...
- On the other hand, food supply would be regarded as a ____-____ control ...
- A weather-related event, such as a drought, would be called a ____-____ control.
- At high population densities, ____, _____, _____, and _____ all would increase.
parasitism, disease, predation, competition
- A group born into a population at the same time is called a
A type III survivorship curve (high juvenile mortality; a reverse J-shape) is shown by
- most marine invertebrates.
- Type III is shown also by
insects, fish, amphibians, and reptiles, all creatures with large litter size.
- The proximate and primary cause of human deaths worldwide is
- Population ‘explosion’ can be caused by
increasing K, new habitats, removing limiting factors, or better medicines.
- The first human populations occurred in the
grasslands or savannah habitats.
- Later, humans adopted grasses as the basis for
agriculture and the construction of human civilizations.
- The largest decrease in human population size was caused by
a disease, the bubonic plague.
- If human population growth actually fell to ZPG level, it would take ___ years...
- The most reasonable and reliable way to limit population growth is
the decrease the birth rate.
- A rapidly growing population shows an ‘age structure diagram’ that is
a pyramid with a very broad base.
Developing (less industrialized) countries tend to be _______ from ZPG.
- Cycling of nutrients and flow of energy between community and the environment ...
- Primary producers are _____, primary consumers are ___ __ ___,...
plants, herbivores like cows, wolf
- A combination of only ____ and ____ could be a sustainable...
- Without decomposers, ____ and ____, most nutrients would...
- The word ‘trophic’ means literally
- Primary producers depend only on
the available energy from outside sources, not other trophic levels.
- For a terrestrial ecosystem, the ultimate source of energy ...
- Most of the energy within an ecosystem is ultimately lost ...
heat from metabolism.
- Detritivores consume ______ or ___ ___ ___ and, thus, must be...
particulate or bulk dead organic material
- Decomposers, bacteria and fungi, are the most ____ organisms,...
- Accumulation of toxic materials as nutrients move through ...
‘Net primary productivity’ =
energy stored in plant tissue – energy used in cell respiration.
- Primary producers occur at the bottom or base of a
‘pyramid of energy.’
- Energy does not cycle through a(n)
- Most of the water vapor in the atmosphere on earth comes ...
evaporation from the oceans.
Carbon is stored in
living biomass, fossil fuels, rocks, or shells of animals.
- Carbon can occur as
dissolved carbonates or bicarbonates, carbon dioxide, or plant cellulose.
- Carbon can be put into the atmosphere by
respiration, volcanoes, burning coal, or diffusion from the ocean.
- In the atmosphere, carbon dioxide is currently increasing ...
- Carbon enters animals in the form of
- The main source of increasing greenhouse gases in the atmosphere...
the burning of fossil fuels.
- The greatest concentration and source of nitrogen on earth ...
- Crop rotation involving _____ can be used to replace or ...
- Plants utilize nitrogen in the forms of
ammonia and nitrates.
- Sharp increases in nutrient, especially ____ and ____, concentrations...
Nitrogen and Phosphorus
- Heterotrophic organisms include all those except
- All of the major macronutrients except _____ have an atmospheric...