20.1 Population Growth Flashcards
What is Population Density?
The number of individual organisms in a given area or volume
What is the equation for population density?
D = N/A
What are the three theoretical distribution patterns of populations?
Uniform, Random, and Clumped
What are distribution patterns influenced by?
The distribution of resources in a habitat and the interactions among members of a population, or members of a community
What is Clumped distribution?
When members of a population are found within close proximity to each other
What is uniform distribution?
When individuals are evenly spaced over a defined area
What does a population’s size depend on?
How much and how fast it grows
What four processes can change the size of a population?
Births, Immigration, death, emigration
What is the formula for change in population?
[births + immigration] - [deaths + emigration]
What is Population Explosion?
When a population grows so rapidly that it spreads before it can be contained
What is Population Crash?
When a population decreases very rapidly
What is the formula for growth rate?
change in Population/change in time
What is Per Capita Growth rate?
The change in population size per individual
What is formula for Per Capita Growth Rate?
Change in population/original number of individuals
What is Biotic Potential?
The highest per capita growth rate
What factors influence Biotic Potential?
The # of offspring per reproductive cycle
The # of offspring that live long enough to reproduce
The age of reproductive maturity and the number of times that individuals reproduce in a life span
The life span of the individuals
What is the Lag Phase?
The initial stage of exponential growth where there are only few organisms able to reproduce
What is the Stationary Phase of exponential growth?
When the birth and death rate are equivalent
What is Carrying Capacity?
The theoretical maximum population size that an environment can sustain
What are the 3 types of factors that can limit a habitats carrying capacity?
Density Dependant Factors
Density Independent Factors
What are some density dependant factors?
Parasites and disease. Finding prey
What are some density independent factors?
Harsh weather
What is Environmental Resistance?
The combined effects of the various interacting limiting factors
What does R-selected strategies mean?
When a species produces close to its biotic potential
What are the characteristics of species with r-selected strategies?
They have short life spans, early reproductive age, and they produce large broods of offspring
What does K-selected strategies mean?
When a species lives close to their carrying capacity
What are the characteristics of species with k-selected strategies?
They have few offspring per reproductive cycle , they often take a relatively long time to mature and live a relatively long time
