4.4 Trophic Levels

TROPIC IS TO FEED

trophic levels are levels of which animals in an ecosystem feed in, including producers, primary consumers, secondary consumers, tertiary consumers and decomposers

CARROT PLANT :            CARROT FLY                      FLY CATCHER                SPARROW
is a producer, transfer's        primary consumer,                 carnivore, secondary             top carnivore,
light energy into      -----> takes in chemical energy -----> consumer, takes in the -----> tertiary consumer
 chemical energy                of the plant into chemical       chemical energy of the         the sparrow turns the
through photosynthesis.      energy of the fly.                   carrot fly and turns it into    chemical energy of the
                                                                                          the chemical energy of the   flycatcher into the
                                                                                          fly catcher.                         chemical energy of the
                                                                                                                                     sparrow

****************

****************

****************

****************

****************

****************

***************************

********************

**************

******

**

DEATH all living organisms die at one point, at this point they get broken down by a group of organisms called decomposers, examples of decomposers are funghi and bacteria, decomposers break down dead animals into nitrates and phosphates.

4.3 Quadrates samples

using the quadrate technique in sampling the distributions of organisms in their habitat.

the sample has to be :
-  random ( not biased )
-  representative ( large enough )

how to carry out quadrate SAMPLES:
-  separate the area in the field into a grid working like the x y coordinates of a graph
-  generate 2 random numbers representing the x coordinate and the y coordinate
-  find the coordinate on the graph, and then in the real area
-  count the number of species you are trying to compare in that particular square
-  the experiment is repeated

REPRESENTATIVE sample
a representative sample is one large enough, the bigger the better, the larger the sample is the closer it is to the real value of the field.

the data is recorded in a table, the average is found ( number of species in all data collected/number of quadrates)
this experiment cam show the average population of a particular species in one particular area, results can also be used to compare the population of the same organism in another area.

4.2 QUADRATES

use of quadrats to estimate population size of a organism in two different areas.

QUADRATING :: are based on squares, these squares can be made out of any material
they are used to sample different areas by counting populations in the square to give an estimation of the size of the community and so results can be compared with the results from another area.

4.1 ECOSYSTEMS

TERMS USED TO DESCRIBE ECOSYSTEMS

HABITAT - abiotic
includes abiotic factors ( non biological )
- cycle of daylight
- temperature
- climate
- rainfall
- humidity
- slope of land (aspect/gradient)
- geology
- latitude
- longitude

COMMUNITY OF ORGANISMS - biotic
the populations of different species that are interactive in a habitat
population : number of individuals of a particular species
species: organisms that reproduce fertile off spring
interacting : feeding (foodchain / food webs)

ECOSYSTEM :: our ecosystem is a community of organisms in a particular habitat, the community is made up of different species interacting within that particular habitat.

PLANT FERTILISATION

          growth of pollen tube
pollen grains on the sigma germinate and a tube begins to grow downwards towards the ovule.
this tube is called the pollen tube.
the male nucleas from the pollen grain uses this tube to travel down and into the ovule.

          fertilisation
when the male nucleas travels down and into the ovule it fertilises the ovule.
this leads to the formation of the zygote which grows into the embryonic plant.

          seed formation
the outside of the ovule turns into the seed coat or testa
the testa not only holds the zygote which is the embryonic plant but it also contains the cotyledons which are food stores which will support the plant until it grows leaves and is able to make their own food.

          fruit formation 
the thickening of the walls of the ovary (carpel) combined with sugar and protein that the plant gives up forms the fruit.

Wind Pollination

wind pollination
transfer of pollen grains through wind

anther ----air/wind----> stigma

adaptations to suit this type of pollination
- light weight
- wing features to allow it to move in the air/wind more efficiently
- Anthers stick out far from flower so it is exposed to the wind therefore can be carried away easily
- Stigmas will stick out far from the flower and has a large surface area so that it can catch pollen grains as they pass through the air.

these plants do not need to attract insects therefore it will not have colour, scent or nectaries.

Insect Pollination

pollen --> is a small structure which contains the male nuleu
pollination --> transfer of pollen from an anther to the stigma.
cross pollination --> when pollen goes from one plant to another it is called cross pollination

insect pollination --> is pollination that takes place by insects
therefore it is necessary for the plant to attract insects
factors that make the plant attract insects:
- coloured petals
-scented
- value for the insect - the plant contains food for insects such as nectaries which produces fructose sugar and pollen which for some plants is a source of protein.