Lecture 9 Flashcards
Endemism
the phenomenon where a species is native to and exclusively found in a single particular geographic region
* Often due to historical isolation, unique environmental conditions
Cosmopolitan
the phenomenon where a species can be found almost anywhere on earth
5 characteristics of population distribution
- Geographic range
- Abundance
- Density
- Dispersion
- Dispersal
Dispersion
spatial arrangement or distribution pattern of individuals within a population across a given area of habitat
Clumped dispersion
- Individuals are clustered together in groups within a population.
- In response to uneven distribution of resources
- Such as food, water, or suitable habitat
- Clumped around distinct ‘patches’ of resources
- Due to social behaviours, cooperative interactions, or mating
Patch
a localized and distinct area within an ecosystem that has a concentration of essential resources
Uniform dispersion
- Individuals are evenly spaced throughout the population
- Associated with competition for limited resources
- Individuals maintain a more uniform distance to minimize resource competition
- Associated with territorial behaviours and antagonistic interactions
- Due to the presence of inhibitory substances
Allelopathy
phenomenon where individual organisms release chemicals into the environment that influence the growth, germination, or development of other nearby organisms
Random dispersion
- Individuals are distributed without any specific pattern or order
- Often when no strong attraction or repulsion between individuals
- Due to random dispersal mechanisms
- Such as wind or water dispersal of seeds
Abundance
total number of individuals of a species within a defined area
Density
number of individuals per unit area or volume
Methods to measure or estimate population size?
- Quadrat
- Transects
- Point counts
- Mark recapture
- Remote sensing
Principle of allocation
when resources are devote to one use, they cannot be allocated to another
