BIOL 1911 Chapter 54.2: 54.2 – Diversity and trophic structure characterize biological communities

50 views3 pages
54.2 Diversity and trophic structure characterize
biological communities
Ecologies can be characterized by certain general attributes
o Diversity
o Feeding relationship of their species
o The control of a few species on a community structure (its composition, relative abundance and diversity)
Species Diversity
Species diversity of a community = the variety of different kinds of organisms that make up the community
o Species richness = number of different species in the community
o Relative abundance = proportion each species represents of all individuals in the community
Ecologists calculate indexes of species diversity based on species richness and relative abundance
o Ex: Shannon diversity (H)
Determining the number and relative abundance of a species in a community can be challenging
o Because most species in a community are relatively rare, it may be hard to obtain a sample size large enough
to be representative
o Can also be difficult to identify some of the species in the community
If some unknown organisms cannot be identified on the basis of morphology alone, it is useful to
compare all or part of its genome to a reference database of DNA sequences from known organisms
Researchers are increasingly using DNA sequencing for species identification as it becomes cheaper
and as DNA sequences from more organisms are added to comparative databases
o Can be difficult to census the highly mobile or less visible members of communities
Microorganisms, deep-sea creatures and nocturnal species
Ecologists now commonly use molecular tools to help determine microbial diversity given the small
size of microorganisms
Diversity and Community Stability
Ecologists manipulate diversity in experimental communities in nature and in the laboratory
Many experiments examine the potential benefits of diversity
o Ex: increased productivity and stability of biological communities
H y  a…
o More productive
o Better able to withstand and recover from environmental stresses
o More stable year to year in their productivity
o Produce more biomass (total mass of all organism in a habitat)
o More resistant to invasive species
find more resources at oneclass.com
find more resources at oneclass.com
Unlock document

This preview shows page 1 of the document.
Unlock all 3 pages and 3 million more documents.

Already have an account? Log in

Get access

Grade+20% off
$8 USD/m$10 USD/m
Billed $96 USD annually
Grade+
Homework Help
Study Guides
Textbook Solutions
Class Notes
Textbook Notes
Booster Class
40 Verified Answers
Class+
$8 USD/m
Billed $96 USD annually
Class+
Homework Help
Study Guides
Textbook Solutions
Class Notes
Textbook Notes
Booster Class
30 Verified Answers

Related Documents

Related Questions