Download anwers

7) Aquatic Ecosystems 2.9
Name _______________________
1) Watch Aquatic Biomes Freshwater and Wetlands and Estuaries
https://www.youtube.com/watch?v=tU2F36Y3AdU This video describes three of the most diverse
aquatic biomes. What species are found in each?
a) Littoral Zone:
Producers: cattails, bulrushes, water lilies, algae, phytoplankton (protists, bacteria, algae)
Consumers: zooplankton, crustaceans, insect larvae, snails, flatworms, hydra, frogs, fish, turtles, snakes
b) Wetlands:
Producers: algae,
Consumers: deer, spider, birds, crustaceans, muskrats, herons, mosquitoes, flies
c) Estuaries:
Producers: salt marsh grasses, algae, phytoplankton
Consumers: worms, oysters, crabs, fish, water fowl
d) How are the abiotic factors of the three areas similar to each other and different from other biomes?
All aquatic systems have easy access to water. These are all rich biomes because they are shallow and
have easy access to light and anchorage. They also all receive nutrients washed down by rivers. The
specific examples shown are all in temperate zones, but they can also be found further north (much
shorter growing season and lower temperatures) and they can be found further south.
e) How are the abiotic factors different in these three regions?
The littoral zone is just a thin line compared to the wetlands and is more susceptible to waves and wind.
The estuary is very different from the other two because it involves salt water and great variations in
water due to the tides.
2) Tasmania is to the south east of Australia and has a warm temperate climate with four distinct seasons.
a) Examine the Tasmanian Marine Food Web Diagram
http://www.parks.tas.gov.au/file.aspx?id=24583 and use the species cards
http://www.parks.tas.gov.au/file.aspx?id=24582 to draw arrows on the diagram.
There are 27 specie cards including the Sun and their numbers are roughly in order of their position in the
food web. Hand out one per person and then have them pass them on. A copy of the diagram could be
handed out to each student or one per small group. If you fold as indicated and cut the bottom cm off, the
information for each species can be glued onto a small file card. These can be used to play an Ecosystem
Card Game but you will need to make two sets.
b) What is good and what is bad about the placement of detritus and the Sun in this diagram?
Placing the Sun at the top and detritus at the bottom reflects where they are found physically but does not
reflect their ecological role. This is a web of energy flow so the Sun should be at the bottom and detritus
at the top. Furthermore, they are not organisms. Detritus is the dead organic matter and the final source of
food energy which is decomposed by bacteria to recycle the nutrients to the producers. The decomposing
bacteria should be at the top and it should not have an arrow from the Sun. That arrow should point to the
cyanobacteria which are generally considered to be part of the phytoplankton.
c) What aspect of the food web does the diagram show clearly?
It shows that it is very complicated and interlinked. It shows the flow of energy that is mostly up the
chain clearly because of where the species were placed. It shows how there are longer food chains in
marine ecosystems and that many organisms feed at a variety of trophic levels. Note: Some of the
labelling is confusing. Echniderms are starfish/seastars and urchins. Crustaceans includes krill and rock
lobster. Invertebrates includes crustaceans, echniderms, shell fish, squid and octopus. Sea mammals
include whales, dolphins and seals. Bacteria is drawn on the diagram as if it were cyanobacteria
(producers) but the card has them eating detritus, so they must be decomposing bacteria. Many cards
mention algae which could be cyanobacteria, phytoplankton or kelp.
d) What aspect of the ecosystem is poorly represented?
It does not show a realistic pyramid of biomass or energy and definitely not numbers. There should be
many more producers than herbivores and many more secondary consumers than tertiary. All arrows
should point to detritus and decomposing bacteria.
e) What is the longest food chain? Name the organisms.
Here is one with nine; Phytoplankton –> micro zooplankton - > krill -> anchovy -> jack mackerel - >
baaracouta -> blue fin tuna -> to human, great white shark or orca.- > bacteria
f) Suppose that one species was to go extinct. Which disappearance would have the greatest effect on
the rest of the food web? Which would have the least effect? Explain.
Phytoplankton: Knocking out a producer will have lots of effect because it will affect everything above it
unless another producer can fill in. Phytoplankton lives on the surface and can’t be replaced by the kelp
or sea grass which must be anchored to the bottom. The phytoplankton card says it produces 70% of the
world’s oxygen! The phytoplankton links to krill and anchovy are the foundation of this whole ecosystem
– just look at all the connecting lines!
For the least effect, you might nominate the specie which has the fewest arrows connecting it either above
or below, perhaps the little penguin or southern right whale. They eat organisms that many others eat and
they are eaten by organisms that eat many others, so they won’t be missed, much.
3) Watch Life in a drop of water 4:30 – 21:00 https://www.youtube.com/watch?v=_cpBK2t0Yeo
a) What creatures can you see in pond water? Very detailed- can skip some of middle
Producers: bacteria, algae, protists, volvox, spirogyra (pond scum), euglena, diatoms
Consumers: protozoa, paramecium, blepherisma, spirostomum, dileptus, lachrymolia olar, stentor,
vorticella, busaria, didinium, amoeba, rotifer, daphnia, cyclops, hydra,
b) Why are these tiny organisms important? 20:20- 21:00
Produce oxygen, base of food chain, study genetics, diseases,
c) What larger pond creatures can you see in the Hidden Life in Pond Water
http://wn.com/pond_microorganisms 4 minutes beautiful photography.
Water fleas, bryozoa colony, mayfly nymph, mosquito larvae, water mite, ostracod, ciliates, hydra,
Textbook Consolidation: Read pages 60 - 62 and answer questions 1, 3, 6