14.5 Ecological Succession
KEY CONCEPTEcological succession is a process of change in thespecies that make up a population in the community.
14.5 Ecological Succession
Succession occurs following a disturbance in anecosystem and can affect population size.
•Succession regenerates or creates a community after adisturbance.
–a sequence of biotic changes
–damaged communities are regenerated
–new communities arise in previously uninhabited areas
14.5 Ecological Succession
•There are two types of succession.
–primary succession — started by pioneer species
Ex: Glacier, NewIsland
Key here: soil needs to be created so the process is much longer
14.5 Ecological Succession
•There are two types of succession.
–secondary succession — started by remaining species
Ex: Forest fire, flood,earthquake
Key here: soil is already present; surviving species colonize andhave to start over; process is not as long
14.5 Ecological Succession
POPULATION BIOLOGY
•Individuals of one species simultaneously occupying thesame general area, utilizing the same resources, andinfluenced by similar environmental factors
–2 factors concerning populations
-fluctuations in population size
-factors that regulate populations.
14.5 Ecological Succession
POPULATION DENSITY
•the number of individuals per unit area or volume
Measuring Density
It is usually impractical or impossible to count all individuals in a population, so ecologists use avariety of sampling techniques to estimate densities and total population size.
1. You can count all individuals in a sample plot, or quadrant.These estimates become more accurate as sample plots increase insize or number.
2. You may also estimate by indirect indicators such as number ofnests or burrows or by droppings or tracks.
3. Finally one may use the mark-recapture method. In the mark-recapture method, animals are trapped within boundaries, markedand after time retrapped.
14.5 Ecological Succession
POPULATION DISPERSON-how organisms are spreadout in a population
•CLUMPED
•UNIFORM
•RANDOM
14.5 Ecological Succession
SURVIVORSHIP CURVES=Survivorship curves plot thenumbers in a cohort still alive at each age
•SKETCH THE SURVIVORSHIP GRAPH ONTHE BACK OF YOUR PRE-LAB SHEET
