Characteristics of Populations
A group of individuals of the same species living in the same geographical area
Population
the maximum number of organisms that can be sustained by the available resources over a period of time
carrying capacity
- individuals compete for nest space, food, light, etc, with others of the same species
interspecific competition
Draw the human population graph
flat then launching almost straight up
How many humans are on Earth at this point in time?
about 7.8 billion
The number of individuals of the same species that occur per unit area or volume
Population density
Why are some population growth graphs geometric and others exponential?
geometric -- only reproduce at certain times of the year
exponential -- can constantly reproduce
Give an example of a symbiotic relationship
E.g.s -- bacteria and me, fungus and trees, sharks and remoras, ...
biodiversity hotspots
the areas on Earth with the most biodiversity per square kilometer
Sketch the 3 main scenarios for human population size in the future
continued growth, stabalization, decline
the population number divided by the total area
crude population density
The quadrat method of population size sampling is only good for ____ species. (i.e., what characterstics must all the species sampled have in common?)
Sessile -- non-moving
Reproduction fails to equal the mortality rate due to low density
Allee effect
ENDEMIC SPECIES
Any species only found in one area (e.g., one lake, certain mountain tops, ...)
What are the 3 main population pyramid categories?
growing, stable negative
the population number divided by the usable area
ecological density
Give 2 examples of density-dependent factors and 2 of density-independent factors affecting population size/growth.
answers will vary
dd -- habitat & food availability, infectious disease spread, ...
di -- natural disasters, accidents, poisoning, weather, ...
Name the 3 kinds of symbiotic relationships
Mutualism, Commensalism and Parasitism
List 3 changes to human activity that increased our carrying capacity on Earth.
tool use, agriculture, industrial revolutions
List 4 ways that the return of wolves to Yellowstone National Park impacted the local ecology (100 pts/example).
How many wolves given
Given a wolf population density of 0.05 wolves /km2 in a study area that is 10 km by 55 km
27.5 wolves
For the recapture method of counting, 25 animals were marked. Later, 5 of the 20 animals recaptured were marked. What is the total size of the population for this animal?
100
What is habitat fragmentation and why can it negatively affect at-risk species?
Habitat fragmentation is when habitat is broken into pieces. Negative effects include: barriers for movement; the edge effect; means different food and nests; fragmented habitat gives introduced pets and humans more access to the habitat
negative growth population so we use a lot of resources; large country (transportation), winter (heating), have lots of "resources" (wasteful); consumer culture; wealthy; ...
Ask 5 important questions about covid-19 and population (100 pts / question)
Has human population be significantly affected yet? What percentage of population globally/nationally have been affected? died? ... Why do infection rates not seem to be density-dependent, etc.