Community ecology

Koala Conga Line….

Community- groups of interacting populations

• Can be potentially influenced by interactions with other organisms

• Primate behavior shaped by interactions with other primate species

Some definitions

• Niche- a way to define the role an organism plays in its environment- multidimensional

• Sympatry- when two organisms share a habitat• Congeneric- within the same genus (taxonomic

category)

When similar species share...

• One may go extinct

• There may be evidence of behavioral character displacement (when one species shifts its niche)

• Share if– Resources are not limited– There is an area where they don’t overlap

(physical and dietary)

• Trophic structure chart (11.1- coursepak)– Example: plants eaten by hippo, hippo eaten by hyenas, hyenas eaten by lions, lions eaten by vultures. – Note trend in population size for each category– Primate/plant interactions at the bottom– Primate impact on leaf

biomass (1%) compared

to insects (15%)

Ways to look at community

• Biomass of everything (coursepak- Fig 11.2)• Biomass of mammals (coursepak Fig 11.1)• Body weight representation (Robinson graph handout)

Ways to look at community

– Note- animals make up small part of community– mammals make up an even smaller part– Primates very small!

• Guilds-animals that occupy similar niches (role played in environment)- use resources in similar ways despite being very different organisms.

• Figure 14.4 - Avian guilds (in coursepak) – Note differences between forests

– Note how partitioned

Ways to look at community

Example 1- Howling monkeys and leaf cutter ants

Ants and Howlers

• Both eat tremendous amount of leaves

• But only overlap on 7 out of 40 plant species

• Howlers, majority of diet New leaves

• Ants almost entirely eat Mature leaves

Example 2- Howlers and Sloths

• Can have up to 80% overlap in diet.

• But sloths eat little (lower BMR)

Example 3- Malaysian Fruit eaters

Malayan Fruit feeders

• Primates eat unripe fruits, hornbills eat ripe ones

• Primates feed in upper canopy along with 3 or so squirrel species

• Squirrels eat seeds, primates fruit flesh

• Primates supplement with leaves, birdds with insects or other fruits.

Coevolution

• Between plants and animals

• A relationship developes between two organisms such that, as they interact with each other over time, each exerts a selection pressure on the other.

• Evolution of each becomes interdependent on that interaction

Some primate examples

• “positive relationships”

–Seed dispersal

–Pollination

• “Negative relationships”

–Seed predation