Invertebrates Flashcards
Reiss., 2018
Microscopic invertebrates are defined as ranging from 20 micrometres to 200micrometres in length.
Montagna et al., 2002
Macroscopic invertebrates are typically larger than 500 micrometres
Reiss., 2018 (2)
Protozoans are microscopically small, heterotrophic, unicellular eukaryotes.
Robertson et al., 2000
Meiofauna are intermediate in size between the macrofauna and microfauna and include both temporary and permanent meiofauna
What are the two size groups within invertebrates?
1) Microscopically small
- protozoa
- meiofauna
2) Macroscopic metazoan invertebrates
Describe protozoa amoebae
1) Cytoplasm is divided into clear external ectoplasm and a more fluid internal endoplasm
2) Pseudopodia may be lobopodia (quite wide with rounded tips).
Name two protozoa ciliates
1) Stentor
2) Frontonia sp.
What dominates the open water in both marine and freshwater environments?
Microscopic crustaceans (zooplankton)
Define plankton
the small and microscopic organisms drifting or floating in the sea or fresh water
Give some examples of microcrustacea
Cladocerans and copepods
Give an example of a protozoan
Cyrthophorid ciliate
Give an example of a species of meiofauna
Bdelliod rotifer
Give two examples of a species of macrofauna
Asellus aquaticus
Gammarus pulex
Why are protozoan ciliates important?
They feed on bacteria and flagellates, which leads to high productivity.
Why are meiofauna important?
They offer a significant contribution to energy flows and are thought to be the most abundant element of any freshwater community
They also impact the ecosystem in a way that is not representative of their size, influencing microbial metabolism, cycling of organic matter and contributing significantly to total production and biomass
