Download Food Chain

Ben Walker-Savage
AIM:
To investigate, identify and determine the relationships between organisms in a decomposer ecosystem.
HYPOTHESIS:
That the relative number of different species of organisms can be used to determine their relationships in a food chain or food web based on the biomass/number pyramid.
MATERIALS:
Plastic collection bottles, capture colander, plastic garbage bags, tweezers, magnifying lens,
METHOD
Separate contents of compost Bin into 4 garbage bags.
Each class then counts and collects invertebrates and sorts according to type using a field guide or key
Each species is sketched and identified with some information researched about species characteristics, feeding habits, reproductive cycle etc.
Results are graphed (frequency vs. species) and combined with other class results.
Arrange specie types according to frequency and if possible infer feeding relationships (most of these will be tertiary feeders as the micro organisms are the primary
decomposers)
Construct three possible food chains based on what organisms you found
Construct a possible food web composed of organisms you found
DISCUSSION
1)
2)
3)
4)
5)
6)
What do all food chains start with?
What is different about this type of ecosystem and the food chains in this ecosystem?
How many different types of organisms were you able to identify?
Would there be others likely to be there that you were unable to identify? Why?
What have you learnt about decomposer/compost ecosystems?
What shortcomings were there in this experiment?
CONCLUSION
State whether you have achieved your aim.
What are your findings in this experiment?
YEAR 9 SCIENCE – ECOLOGY - COMPOST BIN INVERTEBRATE COUNT
Combined count
Invertebrate Name
Mr Tomazi Group 2
Invertebrate Count
Mr Tomazi Group 3
Mr Walden Group 4 Total
Centipedes
Earthworms
Slaters
Mites
Earwigs
Woodlice
Spiders
Millipedes
Ants
lice
Slugs
Maggot/fly
Mole cricket
Springtails
Total Number of
Invertebrates
44
24
0
17
7
10
2
3
0
2
1
0
1
0
111
16
14
6
5
3
0
3
0
2
0
0
0
0
0
49
37
14
24
0
3
0
2
1
1
0
1
1
0
1
85
97
52
30
22
13
10
7
4
3
2
2
1
1
1
245
CLASS COUNT
Invertebrate/common
name
Centipedes
Earthworms
Invertebrate/Scientific Picture/Diagram
name
Chilopoda
Annelida
Description/Information
1 pair of legs per body segment, 1 pair of poison claws/fangs underneath the head,
Antennae present, Simple eyes. The last pair of legs in many centipedes is often
strong and brightly coloured and although look quite dangerous and venomous are
only used to grasp prey or wave in a defensive display. The bite of centipedes may
be painful to humans but is not deadly and usually only results in localised swelling
and irritation. Male centipedes usually spin a small web onto which they deposit a
sperm packet for the female to pick up. In some species there may be a short
courtship dance or tapping of antennae before the female is encouraged to take the
sperm packet into her genital opening. Eggs may be laid in groups or singularly
under a rock or log, in the soil or under bark and may or may not be guarded by the
female depending on the species. Centipedes are predatory and will kill and
consume a variety of other invertebrates such as spiders, molluscs, many insects,
slaters and other centipedes. Some have been observed feeding on small
vertebrates such as frogs, mice and small geckoes. Prey is usually immobilised by
venom injected through the fangs and then torn into pieces by the mandibles and
the soft parts are eaten. The centipedes control how many bugs are in the
ecosystem, in this case they feed on the other insects so there isn’t too many
Long cylindrical shaped, bodies made up of many similar segments, No appendages,
No antennae, no obvious head end.
Earthworms are hermaphrodites, which mean that each animal has both male and
female reproductive organs in the same body. Earthworms lay their eggs in a
cocoon that is then deposited in the soil. On hatching the young worms resemble
small adults and will grow continually until they reach maturity. Most earthworms
feed on a wide variety of organic matter, primarily detritus and algae. Earthworms
are considered to be beneficial animals because as they move through the ground
feeding, they ingest huge quantities of soil accelerating the nutrient cycle and
increasing its productivity. As earthworms feed they pass out what they do not
need in the form of castings. These castings are high in nutrients and are in turn
food for other animals.
Count
16
14
Slaters
Isopoda
1 pair of prominent antennae and 1 pair of inconspicuous antennae, 7 pairs of legs,
Simple or compound eyes composed of single ocellus or many closely associated
ocelli respectively, Obvious uropods. In slaters the male transfers a sperm packet to
the female using his modified seventh legs. The eggs, of which there may be up to
100 or more are laid into a brood pouch which is a chamber formed by cuticle
outgrowths at the base of the legs. Upon emerging from the brood pouch the young
resemble adults but have only 6 body segments and 6 pairs of legs. They will gain
their last segment and seventh pair of legs at later moults. Slaters are omnivores or
scavengers and feed upon decaying vegetable matter and associated fungi and also
on animal matter. They form an important link in the food chain by recycling dead
and decaying matter.
6
Mites
Acari
4 pairs of legs, although some juveniles only have 3 pairs gaining a forth pair with
their first moult, No external segmentation of the abdomen, individuals appear as a
single body mass, Never have antennae. Reproduction in mites and ticks is very
variable with some species mating through the direct transfer of sperm via coupling
of the genital regions. Other species transfer sperm indirectly with the male placing
a sperm droplet on the genital opening of the female with his legs or chelicerae.
After fertilisation the female will usually lay her eggs in the substrate where they
are left to hatch. The first free-living stage is called a larva and has only 3 pairs of
legs. After the first moult it will gain its fourth pair of legs and will moult several
more times before becoming a mature adult. Most species of mites are predatory
and will feed on a variety of small invertebrates, while others are more herbivorous
and often feed on plant sap, sometimes causing damage to agricultural crops and
garden plants. Spider mites are notable garden pests, many beneficial mites help
degrade organic matter in your compost pile. For example, mold mites feed
primarily on yeasts in organic debris.
5
Earwigs
Dermaptera
Flattened elongated body, Heavily sclerotised pincer-like cerci. Females have
straight cerci with an inward pointing tip and males have curved cerci, 2 pairs of
wings. The forewings are short and protectively hardened. The hind wings are
membranous and folded in a fan-like way underneath the forewings when not in
use. Some species are also wingless, Chewing (mandibulate) mouthparts,
Moderately long antennae. He name 'earwig' come from a European myth that
these insects had a habit of crawling into human ears. Earwigs mate end to end,
often grasping each other's pincers. Female earwigs are able to store sperm for
several months before fertilisation. A female will lay hers eggs in a burrow she has
excavated or in natural crevices in the soil, where she will stand guard protectively
until the young hatch. The female guards the eggs from predators and constantly
turns and cleans them, preventing fungus diseases. Most species of earwigs are
omnivorous and eat a wide variety of plant and animal material. Many species live
primarily on a diet of plant matter, both living and decaying. They also consume
dead insects and other organisms, while some species prey on live insects. The cerci
are often used to hold food and carry prey after it has been killed.
3
Spiders
Araneida
4 pairs of legs, Usually 4 pairs of eyes although some species may have less, 2
discernible body sections; the cephalothorax which contains the head fused with
the thorax; and the abdomen which houses the internal organs, Spinnerets at the
end of the abdomen, which are used for spinning silk threads used for a variety of
purposes such as the construction of webs, snares and retreats in which to live or to
wrap prey, Fangs (or chelicerae) used to deliver venom to kill prey, for defence, to
capture and crush prey and to dig and excavate burrows. Only after their
final moult do male spiders become sexually mature. At this point they stop feeding
and spend all their time and energy trying to find a female to mate with. When a
mate is found the male spiders will transfer his sperm to the female. After mating
the male will either die or be eaten by the female. A short time later the female will
lay her eggs into a silken sac, which varies in shape and size depending on the
species. Most species of spider are active at night and all are predatory, feeding on
a wide range of other invertebrates. Cannibalism may also occur among spiders
especially where there is overcrowding. Different species of spiders use a variety of
methods to capture their prey, but most usually construct sticky silk webs or
threads to trap potential prey. Other species chase their prey often capturing them
with rapid lunges. Spiders in compost are like a natural pest control
3
Ants
Hymenoptera
Ants feed on a variety of material, including aphid honeydew, fungi,
seeds, sweets, scraps, other insects, and sometimes other ants.
Compost provides some of these foods, and it also provides shelter
for nests and hills. They will remain, however, only while the pile is
relatively cool. Ants prey on first level consumers, and may benefit
the composting process by bringing fungi and other organisms into
their nests. The work of ants can make compost richer in
phosphorus and potassium by moving minerals from one place to
another.
2
Discussion Questions
1)
2)
All food chains start with a primary producer, in most cases the primary producer is a plant. The plant can be debris or alive.
3)
As a year level we were able to identify a total of 245 invertebrates, we found 97 centipedes, 52 earthworms, 30 slaters, 22 mites, 13 earwigs, 10 woodlice, 7
spiders, 4 millipedes, 3 ants, 2 lice, 2 slugs, 1 maggot/fly, 1 mole cricket and 1 springtail. The class I was in only
4)
Yes, there were other organisms in the compost that our class wasn’t able to identify. I think we couldn’t find as many organisms or as big of a variety because we
had a smaller amount than the other two classes and most likely we got the compost from the top without all as many organisms. Most of the organisms are
located in the middle and bottom of compost heaps because it is a temperature they like more.
5)
The main thing I have learnt is that bacteria does most of the decomposing and how important it is to not have to many of one organism because the ecosystem
then becomes unbalanced and doesn’t work properly. E.g. if there are too many centipedes the compost isn’t going to decompose properly because they will eat all
the other organisms
6)
In my opinion the shortcomings were the lack of bugs our class found compared to the other two. Group 2’s count was more than double ours and group 4’s was almost double ours, they both also had a wider variety of organisms
The difference about this kind of eco system is that it is a decomposer ecosystem which means that the ecosystem is breaking down the organic debris by most of
the animals in the food web, the other difference is that is a man made ecosystem
Conclusion
Our class found a total of 49 organisms with a variety of seven different species, 16 centipedes, 14 earthworms, 6 slaters, 5 mites, 3 earwigs, 3 spiders and 2 ants. In this
experiment I also found out about how important it is to have a balanced ecosystem for everything to work properly. I think that I did achieve my aim but it wasn’t to a
scale as big as I would have liked it to be.
Food Chain:
Plant Debris
Micro Fungi
Mite
Centipede
Food Web:
Plant Debris
Dead Insects
Micro Fungi
Earthworms
Bacteria
Mites
Earwigs
Slaters
Ants
Spiders
Centipedes