1. Chapters 5&6 – Populations and Human Growth
Section 5-1:
How Populations Grow

2. 3 important characteristics of a population are its
geographic
distribution, density, and growth rate

3. Geographic distribution
______________________ is just the area inhabited by the population
__________________ is the number of individuals per unit area
Population density
Growth rate depends on several factors; number of _______, number of ______, and the number of ________________ ____________________________
births
deaths
individuals that
enter or leave the population

4. A population _______ if more individuals are born than the number that dies (_____________________)
If birthrate ___ death rate, then the population _________ __________
A population _______ if more individual die than are born (_____________________)
grows
birthrate >death rate =
stays the
same size
shrinks
death rate >birthrate

5. _____________ = when individuals move into an area
____________ = when individuals move out of an area
Immigration
Emigration
Immigration
Emigration

6. There are several different models of population growth;
exponential and logistic
Logistic growth
Exponential growth

7. Exponential growth occurs when the individuals in a population
Needs ________________ & ___________________
reproduce at a constant rate
ideal conditions
unlimited resources

8. We end up with a _______ curve, just continues to go up
J-shape
Exponential growth
doesn’t happen in natural populations for very long

9. Logistic growth occurs when
This happens because _________________________________, the growth of a population slows or stops
a population’s growth slows or
stops following a period of exponential growth
as resources become less available

10. We end up with an ________ curve – things level off
S-shape
Birthrate, death rate, immigration, and emigration can all have an impact of why a populations growth levels off

11. Even when population growth “stops”, it still ____________, but averages out around a certain point
varies a little
__________________ = the point where growth evens out – it is the ______________ of individuals that a given environment can support
Carrying capacity
largest number

12. Section 5-2:
Limits to Growth

13. There are different types of factors that affect the growth of a population
Limiting factor
______________ = a factor that causes population growth to decrease
A ____________________ can also affect the long-term survival of a species as well as population growth
limited resource base

14. ________________________________ = a limiting factor that depends on population size
Density-dependent limiting factor
These factors are only limiting when the population density
reaches a certain level

15. They are more prevalent in large, dense populations
They include competition, predation, parasitism, and disease

16. Competition can occur between members of the ______ species or even members of _________ species
same
different
The more individuals in an area, the _______________________________, the more competition there is
sooner they use up the resources
Competition between species helps drive evolution  when the 2 species are competing for the same resource, there is
pressure to change
to decrease the competition

17. The regulation of a population by predation takes place within the ___________________________, its just one big cycle!
predatory-prey relationship

18. Density-independent limiting factor
__________________________________ = a limiting factor that affects all populations in similar ways,
regardless of population size
They include unusual weather, natural disasters, seasonal cycles, and certain human activities

19. The Midwest has experienced an unusually hot summer this year  the hot weather has affected many populations in different locations, regardless of the size
A large storm, like hurricane Katrina, will affect anything in its path, it doesn’t matter what size it is
Human activities, like housing developments, will also affect anything in its path

20. Human Population Growth
Section 5-3:
Human Population Growth

21. Demography
_____________ = the scientific study of human populations
The goal of demography is to _______________________ of human populations and figure out how populations
examine characteristics
Birthrates, death rates, and age structure help us predict why some countries have high growth rates and some don’t
will change over time

22. Population growth also depends on the age of people within the population
An ______________________ shows the population of a country broken down by age and gender
These diagrams can help predict
age-structure diagram
future growth rates

23. Ex. If there are equal numbers of individuals in the different age groups, it predicts slow and steady growth
Ex. If there are many more children and teenagers, this predicts rapid growth

24. Will humans ever reach their carrying capacity?
Statistics show that the human population is still growing, but not as fast as it once was
A lot of ecologists say that if human growth doesn’t slow more than it has, there could be serious damage to the, environment

25. Section6-1: A Changing Landscape

26. Humans have a vast effect on any ecosystem they become part of
Humans use ________ energy and transport ________ materials as _________________________ combined
as much
as many
all other multicellular species
Some important activities that affect the biosphere are hunting and gathering, __________, industry and
agriculture
urban development

27. Even with the advances in agriculture, there still ended up being _____________ in many parts of the world
food shortages
Science met this shortage with an answer
_______________ = the development of highly productive crop strains and the use of modern agricultural techniques to increase yields of food crops
Green revolution
The green revolution has helped many people greatly and has even helped world food production double

28. With increased food supply came
ecological challenges
Monoculture can lead to insect issues  if they have a large supply of food, their population can
grow rapidly
Pesticides can kill _________ insects, ___________ water supply and accumulate in the environment
Water for irrigation is limited and may run dry
beneficial
contaminate

29. Renewable and Nonrenewable Resources
Section 6-2:
Renewable and Nonrenewable Resources

30. Humans use many resources on a daily basis and we need to remember to protect these resources
Environmental goods and services may be classified as either
renewable or nonrenewable

31. __________________ = a resource that can regenerate if alive or can be replenished by biogeochemical cycles if nonliving
They are not necessarily
Renewable resource
unlimited
_____________________ = a resource that cannot be replenished by natural processes
Ex.
Nonrenewable resource
Fossil fuels
The classification of a resource depends on
its context

32. Sustainable development
______________________ = a way of using natural resources without depleting them and providing for humans needs without causing long-term environmental harm

33. _____ is an important resource – it provides space, raw materials for industry, and soil to grow crops in
Land
Food crops grow best in ______ soil  this can be maintained through interactions between the soil and the plants growing in it
fertile

34. _______ are also important resources – they provide us with fuel, _____________, and produce oxygen
The type of forest determines whether it is renewable or nonrenewable
Forests
create habitats
Deforestation = loss of forests

35. _______ and the organisms that live in them are a valuable food resource
Oceans
Fishing
_______ is considered a __________ resource – the fish can reproduce – but overfishing threatens to harm the resource
___________ = the raising of aquatic animals for human consumption  this has helped to sustain the resource
renewable
___ is a resource we use all the time and rarely think about
Air
Aquaculture

36. ___________ is a __________ resource, but the total supply is limited
Natural habitats like _________ can help to purify and maintain our water supply
Freshwater
renewable
wetlands

37. Section 6-3: Biodiversity

38. Since humans are part of global food webs, we are closely tied to the well-being of other organisms
Biodiversity
___________= the sum total of the genetically based variety of all organisms in the biosphere

39. __________ is considered to be our greatest natural resource and can provide us with many things
Biodiversity
_________ = when a species disappears from all or part of its range
Humans have hunted a number of animals into
Extinction
extinction

40. Endangered species
_________________ = a species whose population size is shrinking and are in danger of becoming extinct
Habitat fragmentation
___________________ = when an ecosystem is split up into smaller pieces or “islands”

41. Different pollutants can be very hazardous to local ecosystems and can harm organisms all along the food chain
Ex. DDT was a pesticide used. It was ______________ and organisms could not eliminate it from their body. The higher up the food chain, the more DDT was found in organisms.
nondegradable
_____________________ = concentrations of harmful substances increase in organisms at higher trophic levels
Biological magnification

42. ______________ = species that are non-native and introduced to new habitats
Because they have no natural predators, the population can grow rapidly and they have an adverse effect on
Invasive species
native species

43. Hot spots
________ are being identified around the world to help us zone in on where organisms are in danger