Download Chapter 4.1 Population Dynamics Notes

Chapter 4.1
Population Dynamics
Notes
Populations of species have three characteristics in common. They are
• __________________________- how many individuals in a given area. The more individuals in an area, the more dense the
population.
• ________________________- also called _________________. It is the pattern of spacing of a population within an area.
There are 3 patterns of distribution
o _______________________ these are organisms that like to have a certain distance between them and the next one.
Penguins exhibit uniform distribution
o ___________________________ these are organisms that tend to travel in groups or packs. Wolves exhibit
clumped distribution
o ________________________ the members of this population are seemingly randomly placed. Dandelion seeds are
blown by the wind, and land randomly on the ground.
SEE YOUR CHAPTER 4.1 READING ON PAGE 93 FOR DIAGRAMS OF THE 3 PATTERNS OF DISTRIBUTION!
•
_______________________- how fast a population grows. There are two models of population growth
o ___________________________________- this shows how a population grows with no limiting factors. The
beginning of exponential growth is slow because there are not many organisms in the population. This is known as
the __________________________. However, the population soon begins to grow rapidly because there are more
organisms that can reproduce. You can see from the example below that this is also called a
____________________________________
o It is important to note that all populations grow exponentially UNTIL some
_____________________________________ slows the population’s growth
o
o
________________________________- also called an _____________________. It begins with exponential
growth, but eventually __________________________ slow the population’s growth.
You can see from the graph below that a population stops growing and stabilizes once it reaches
__________________________. Carrying capacity is the maximum number of species in a population that an
_____________________ can support long term. Carrying capacity is determined by the
______________________ in an environment!
Until a population reaches carrying capacity, there are __________ births and ____________ deaths
Once a population reaches carrying capacity, the number of births __________________ the number of
deaths
If a population exceeds carrying capacity, there are _______________ births and _________________
deaths
Population Range
Another characteristic of populations is the ______________________________. No population, even the human population, can
inhabit all habitats in the biosphere. Organisms that are found in only certain places are said to have a
____________________________________________. Organism that are found on almost all continents are said to have a
______________________________________.
What limits the population range of a population?
Population Limiting Factors
Just like species have limiting factors that ________________ reproduction, numbers of individuals and distribution,
populations have limiting factors that keep a population from _______________________. As limiting factors change, population
____________ changes as well. For example, the availability of food is a limiting factor. If the available food increases, the
population _________________. If the available food decreases, the population size ___________________.
There are two kinds of limiting factors
• _______________________________________- any factor in the environment that limits the population but
______________________ depend on the density of the population. These factors are usually ______________ and include
natural phenomena like drought, flooding, extreme heat and cold, tornadoes, hurricanes, fire, etc. Human activities are also
density independent- pollution, construction, etc. These factors are density independent because it does not matter how dense
the population is, all organisms in the population have an equal chance of dying from these factors.
• _____________________________________- any factor in the environment that ______________ on the density of the
population. The more dense the population, the more individuals die. These factors are usually __________________ and
include predation, disease, parasites, and competition. These factors are density dependent because the more dense the
population, the more likely is for an organism to catch a disease, be killed by a predator, be infected by a parasite, or engage
in competition.
Reproductive Patterns
Different species _____________ in the number of offspring they have every time they reproduce. Organisms are put into two
different groups depending on how many young they have when they do reproduce.
• ___________________- they employ the _______________! These organisms tend to be small, like fruit flies, mice,
roaches, locusts, rabbits, etc. Their strategy is to produce as many young as possible in a short time period to take
advantage of some environmental factor
o This strategy seems to be an adaptation of quickly changing abiotic and biotic factors like food availability or
changing temperatures
o They typically expend little to no energy on raising their young
o Their population’s are usually controlled by ___________________________________________
o They usually do not maintain a population near _____________________________________
• _____________________________- they employ the _______________________! These organisms tend to be larger and
have a long life span, like humans, elephants, birds, etc.
o This strategy seems to be an adaptation to living in environments that are fairly predictable, or show little
______________________
o They typically have few offspring, but invest much time, energy and care in getting their young to
__________________________________________
o Their population’s are usually controlled by ___________________________________________
o