Community Ecology Structure and Species Interaction Connor McNeil and Daniel Crawford

Community EcologyStructure and Species Interaction

Connor McNeil and Daniel Crawford

Community Structure (aka Spatial Distribution)Described by: Physical Appearance: stratification,

distribution, and relative sizes of population and species

Species Diversity (Richness): number of different species

Species abundance: number of individuals of each species

Niche Structure: number of ecological niches, how the resemble of differ from each other and how they interact

Difference in Physical Appearance Terrestrial biomes consist of vegetation

patches Difference in size

Leads to boundries: Sharp edges: distinct Ecotones: Wider, more gradual transition zones

Distribution of Biodiversity• Highest Biodiversity in Tropical Rain Forests

However, High Biodiversity and Low Species Abundance

Latitude: Latitude species diversity gradient : greater diversity in tropics, least at poles (terrestrial systems)

Depth: increases to 2,000m, then decreases, until ocean surface, which has high diversity (aquatic systems)

Species InteractionCompetition and Predation Intraspecific competition: members of the

same species compete for resources Territoriality: Patrolling, marking, and/or defending

home/nest/feeding sight Interspecific Competition: Competition

between two or more species for resources

Competition Interference Competition: one species limits

another’s access to resources Exploitation Competition: species have equal

access to resources, but vary in speed and efficiency of exploitation.

Predator-Prey Relations Predator feed directly on Prey

Individually harmful However, through predation, Prey species limited

in abundance and increased access to food and genetic stock improved

Use eyesight, speed, pack-hunting, etc Pursuit and ambush

Prey Naturally avoid being EATEN!!!

Speed, Detection, Protection, etc. Camouflage, Mimicry

Chemicals: Poison, Irritation, Smell, Bad Taste

Enlargement

Symbiotic Species Both species helped:

Parasitism* Lichens, Bacteria, Algae

*Can be considered special type of predation

Commensalism One species helped; one unaffected

Ex: Raccoons and human garbage

Sources http://www.bbc.co.uk/schools/gcsebitesize/scie

nce/edexcel_pre_2011/environment/populationsandpyramidsrev5.shtml

http://i2.wp.com/naturalunseenhazards.files.wordpress.com/2010/09/raccoons.jpg

http://3.bp.blogspot.com/_Y9-9pUdrfsQ/TASYkDVUQLI/AAAAAAAAAXE/KStyyjVahy8/s1600/IMG_3981.JPG

http://read.uconn.edu/PSYC3501/Lecture02/ http://commons.wikimedia.org/wiki/File:Eucaly

ptus_forest_and_button_grassland.jpg http://www.life.illinois.edu/ib/453/