LEC 23 Flashcards
Population Dynamics
Biosphere
All of the ecosystems on earth
Levels of organization in human biology (SMALLEST TO LARGEST )
Atom/Molecule
Cell
Tissue
Organ
Organ System
Organism
Population
Community
Ecosystem
Biosphere
Ecosystem
consists of a community of organisms and the physical environment in which they live (living and non-living components combined)
Community
groups (populations) of different species that occupy the same geographic area and interact
Population
Groups of individuals of the same species occupying the same geographic area who interact with each other
- groups within a community
Characteristics of Populations - Distribution (3)
The area where we can find a particular population
Also known as its “range”
Found here because the area is suitable to growth & survival
Characteristics of Populations - Population Density (2)
The number of individuals per unit area or volume
Tends to be higher in areas with plentiful resources
Characteristics of Populations - Population Density Trends (2)
- Larger body size of the organism, population density declines
- Smaller body size of the organism, population density increases
Growth
a population will grow when the number of births exceeds the number of deaths
Growth rates
Growth rate = ((# births - # deaths) x 100)) / total population
Biotic Potential
The maximum rate of growth of any population, under ideal conditions
Biotic Potential influenced by:
abundance of resources
(Enough food, water, habitat etc.)
Biotic Potential related to characteristics of the species (4)
- Usual number of offspring per reproduction cycle
- How often each individual reproduces
- Age when reproduction begins
- Ratio of males to females
Doubling Time of a Population
If you know the percent of change (for a period of time) in a population, you can calculate the time for that population to double in size
Doubling Time of a Population equation
Doubling Time = 72 / rate of change
Exponential Growth Also known as
theoretical growth
Exponential Growth Characteristics (4)
Occurs in ideal conditions (no limiting factors)
Population will double in size over a given time
Will continue to grow “unchecked” as long a resources are available
As population grows, the competition increases, may slow down rate of growth
Exponential Growth Graph
“J” shaped