4.9 Carbon Cycle

Photosynthesis : Carbon dioxide and water are combined to form glucose. The carbon dioxide comes from the atmosphere. Photosynthesis is responsible for reducing CO2.

Feeding: Producers are eaten by primary consumers and therefore the primary consumer takes in the carbon that was in the producer and uses this to grow. The primary consumer is then eaten by the secondary consumer and keeps passing through the different trophic levels. All our putting CO2 into the atmosphere through respiration.

Respiration: Releases energy and produces carbon dioxide, thus adding more CO2 to the atmosphere.

Decomposition: Eventually organisms will die and the organic molecules remaining will be broken down by decomposers such as bacteria and fungi. This will result in the release of CO2.

Combustion: The burning of fossil fuels releases CO2. Used for industry and motor vehicles to release energy for their movement. Natural-- forest fires, lightening striking plants and grassland fires.

4.11 Gas Pollution

Sulphur Dioxide is a gas that is a product of the combustion of fossil fuels such as coal and oils.

Sulphur dioxide combines with water and forms sulphuric acid found in condensed water in clouds and when it rains we call this rain acid rain.

Effects on Plants:

Trees and plants are often "burned" (top of tree is usually dead)

Causes calcium and magnesium ions to be leached out of the soil (plant can't grow)

Makes lakes acidic and releases Aluminium ions which causes thickening of mucus in a fish and reduces the ability to take in oxygen

Carbon Monoxide

Produced when fossil fuels such as gas are burned with insufficient oxygen.

The carbon monoxide joins with haemoglobin and forms carbaminohaemoglobin which blocks the haemoglobin from carrying oxygen

4.7 Energy efficieny

Energy efficiency uses a pyramid of energy. Much of the energy from the producer is lost throughout the food chain due to respiration, excretion and heat loss. All of the energy that we started with will come out when the organism dies and its body decomposes. This process of decomposing is done by decomposers.

4.6 Energy substances in food chains

The producer in the food chain converts sunlight into chemical energy. The chemical energy then takes the form of organic molecules such as Carbohydrates, Proteins and Lipids. Consisting of bonds such as :

C-H

C-O

C-C

O-H

C-N

C H O N substances all contain energy. The energy is passed on along the food chain and adjusts to each animal.

4.5c Pyramids

There are 3 different types of food pyramids:

-Pyramids of number

-Pyramids of biomass

-Pyramids of energy transfer

Pyramids of number:

These pyramids illustrate the number of organisms per trophic level, however there are problems with using this method. The pyramids sometimes goes against the laws of thermodynamics and fails to show the energy transfer between trophic levels. They can be effective but are highly limited.

Pyramids of biomass:

Bio=living and mass=g/kg

Biomass is based on dry mass and tends to be measured in kg/area. It is difficult to find out the dry biomass of each organism per trophic level.

Pyramids of energy transfer:

This measures the movement of energy from on trophic level to another. It follows the laws of thermodynamics and cannot be inverted. It is measured in Joules or KJ/m squared/time (seconds/minutes/years). This method is also extremely hard to calculate.

4.5b Food Webs

The food webs of the ecosystem describe the feeding interaction within a community. It shows organisms feeding at different trophic levels. Organisms can have multiple trophic levels, they can also have multiple prey, multiple predators and everything becomes linked. In many cases, animals can both be primary and secondary consumers.

4.5a Food Chains

The food chain connects the Produce-> Primary Consumer-> Secondary Consumer-> Tertiary Consumer

There is 1 organism per trophic level

The food chain shows the flow of matter and energy

4.4 Trophic Levels

-Trophic means to feed

Photosynthesis Herbivore Carnivore Top Carnivore

Producer Primary Consumer Secondary Consumer Tertiary Consumer

Light energy-> Plant chemical energy-> Chemical energy-> Chemical energy->

chemical energy animal chemical energy Chemical energy Chemical energy

All organisms die and are then broken down my decomposers eg. Funghi and bacteria. These break down complex molecules into nitrates and phosphates.

4.3 Quadrates samples

Wes use quadrates to find the population of certain species, in this case daisies. The sample must be random so there is no bias. It must also be representative.

The sample has to be large enough so that the estimate of the population is as close as possible to the real population.

4.2 Quadrates

The image shows a Sand Dune ecosystem which is made up of a number of populations which form the community and the habitat.

There is a fence which splits the Sand Dune region into grazed by cattle and ungrazed.

So there are two different types of areas within an ecosystem and we can choose to study both populations.

The first step is to count the number of individuals in the population. The technique used to do so is called quadratic. Quadrates are made up of squares and can be produced in any material such as wood, metal or string forming a square grid.

These square grids are used to sample the populations of different areas. By counting the number of individuals in the grid, and repeating this numerous times, we are able to gain an estimate of the population.

4.1 Ecosystems

An ecosystem is a community of organisms in a particular habitat.

The study of habitat is non biological (abiotic factors) eg:

-Cycle of daylight/dark (photo period)

-Temperature (local/seasonal/annual)

-Rainfall

-Humidity

-Slope of the land

The community is made up of populations of different species and their interacting with each other. Population is the number of individuals of a particular species. Species are organisms that reproduce to give fertile offspring. The main type of interacting is: Feeding.

Summarise:

Ecosystem-community of organisms in a particular habitat-community of different species interacting.

3.4 Plant Fertilisation

Pollen grains germinate, tube grows downwards. Germination happens with specific species, so only the same type of pollen can germinate. Male nucleus goes through the pollen tube down to the ovule.

In order for a seed to form, the following must happen:

-Fertilisation: Pollen nucleus + ovule= Zygote

-Coating: Outside ovule forms seed coating: TESTA

-Food stores for the seedling: Cotyledons (support plant till leaves come)

-Fruit: Ovary wall thickens, energy put into sugars proteins, which eventually form the fruit.

3.3b Wind Pollination

Through the movement of wind, pollen is transferred from the male part of the plant to another plant's female part.

In order for the pollen to be carried in the wind, it is made to be lightweight and has winglike features to help move effectively through air.

Also, the anthers will hang well clear of any flower structures so that they are exposed to the wind.

The stigma will have a large surface area, featherlike structure to catch the pollen grains as they pass through the wind.

The flower has no scent, no color or nectaries because it is a waster of energy as these features are not needed for wind pollination.

3.3a Insect Pollination

Cross-Pollination is the transfer of pollen (Male nuclei) from one plant to another plant's stigma (female part).

In order for a plan to be pollinated by an insect, the plant must attract the insect.

The plants colored petals and various scents are watch attract the insect, and the insect always returns because they receive fructose and pollen (protein).

Stamen (Male part of the plant):

Anther which produces pollen grains

Filament which supports the anther

Carpal (Female part of the plant):

Stigma is where pollen grains fall

Style which connects the stigma to the ovary

Ovary which contains eggs (ovules)

2.81 Phototropism

-Phototropism is the growth response to light

-As it is positive, the growth is upward, towards the light

-Wherever the light comes from, the plant leans towards, for example if the light is coming

from the side, the plant will bends toward the light

-This is caused my the plant hormones

2.80 Geotropism

-Geotropism is the growth response to gravity

-When the root grows downwards, it is called positive geotropism

-When the root grows upwards, it is called negative geotropism

2.79 Plants and stimuli

-Stimuli are changes in the environment

-Plants have receptors which detect the stimuli and turn those into a response

-The responses often take the form of growth

-There are different types of tropisms (growth from stimuli)

-A tropism involving a response to light is called a phototropism and a response to gravity is called a geotropism

-The connection between the receptor and the response is plant hormones

2.54 Transpiration

-Evaporation changes from the liquid phase to the gas phase, the heat is provided by the sunlight as the structure of the leaf absorbs the light

-Evaporation occurs through the stomatal pores

-Not all of the light is absorbed through chloroplast, absorbed through other cell structure and thus generates heat.

-In the spongy layer, there is a phase change

-The water vapor diffuses down the diffusion gradient and then through the stomatal pore

2.53 Root uptake of water

-Root branches out, creating larger surface area for absorption

-Cell wall extends, thus creating more surface area for more intake of water

-At the bottom of 'root hair' active transport of minerals into the xylem

-Where outside is dilute, and inside the cell is concentrated with minerals, osmosis occurs

-Increase of minerals in cell through active transport increase the concentration which allows osmosis to take place