Lec 24 & 25

Lec 24 & 25 - BIS2B Fall 2009 Foodwebs 2. Foodwebs...

Info iconThis preview shows pages 1–6. Sign up to view the full content.

View Full Document Right Arrow Icon
BIS2B Fall 2009 Foodwebs
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2. Foodwebs are collections of species with . 1. Direct interactions, between pairs of species, Predator kills prey, disease infects host. Balanus barnacle grows over Cthamalus . Trees shade shorter plants, etc.
Background image of page 2
large Daphnia sp. small Daphnia sp. alga + + Our Daphnia example is actually a food web of 3 species. Showing direct interactions. Shorter arrow indicates that less energy harvested by smaller than by larger Daphnia species.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Showing all interactions. Indirect interactions by dotted line large Daphnia sp. small Daphnia sp. alga Indirect negative interaction of large Daphnia with small Daphnia via the algae food. - + +
Background image of page 4
Species together ( ) graze algae to lower concentration than D. galatea needs for equilibrium ( λ =1), higher than needed by D. pulicaria. So, D. pulicaria has a stronger competitive effect on D.galatea than on itself. The competitive effect is indirect, via the resource.
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 6
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 32

Lec 24 & 25 - BIS2B Fall 2009 Foodwebs 2. Foodwebs...

This preview shows document pages 1 - 6. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online