Energy and Ecosystems Flashcards
True or False
Green plants and algae absorb a large amount of the light energy that reaches them.
Photosynthesis transfers light energy to chemical energy.
The energy is stored in the substances that make up the cells of the plants .
The amount of material and energy contained within the biomass increases at each successive stage in a food chain .
This is represented with a pyramid of numbers
Energy is lost at successive stages of the food chain through waste and processes linked to respiration e.g. Movement .
Much of this energy is eventually transferred to the surroundings.
The glucose from photosynthesis is used to produce fat, protein and cellulose
It can also be stored as glycogen
Glucose is the main respiratory product
Green plants and algae absorb a large amount of the light energy that reaches them. False- small
Photosynthesis transfers light energy to chemical energy. True
The energy is stored in the substances that make up the cells of the plants True
The amount of material and energy contained within the biomass increases at each successive stage in a food chain False- decreases
This is represented with a pyramid of numbers False- pyramid of biomass
Energy is lost at successive stages of the food chain through waste and processes linked to respiration e.g. Movement . True
Much of this energy is eventually transferred to the surroundings. True
The glucose from photosynthesis is used to produce fat, protein and cellulose True
It can also be stored as glycogen in plants False- Plants store starch
Glucose is the main respiratory product False- substrate
What is an Ecosystem?
An ecosystem is a community of living organisms in conjunction with the nonliving components of their environment (things like air, water and mineral soil), interacting as a system. These biotic and abiotic components are regarded as linked together through nutrient cycles and energy flows
Complete the notes: introduction to energy transfers…….
An _____________ includes all the organisms living in a particular area and all the non-living (_______) conditions. In all ecosystems there are _________. These are organisms that make their own food
During ________________, plants use energy from __________ and _______ __________ to make ________ and other sugars.
Some of the sugars are used in ____________, to _________ energy for growth. The rest of the glucose is used to make other biological molecules such as __________. These biological molecules make up the plant’s __________ (the mass of _________ material). Biomass can also be thought of as the __________ energy stored in the plant.
___________ is transferred through the living organisms of an ecosystem when organisms eat other organisms, e.g. producers are eaten by organisms called __________ ______________. These are the eaten by ____________ __________, which are consumed by ___________ consumers. This is known as a ______ _________.
An ECOSYSTEM includes all the organisms living in a particular area and all the non-living (ABIOTIC) conditions. In all ecosystems there are PRODUCERS. These are organisms that make their own food
During PHOTOSYNTHESIS, plants use energy from SUNLIGHT and CARBON DIOXIDE to make GLUCOSE and other sugars.
Some of the sugars are used in RESPIRATION, to RELEASE energy for growth. The rest of the glucose is used to make other biological molecules such as CELLULOSE. These biological molecules make up the plant’s BIOMASS (the mass of LIVING material). Biomass can also be thought of as the CHEMICAL energy stored in the plant.
ENERGY is transferred through the living organisms of an ecosystem when organisms eat other organisms, e.g. producers are eaten by organisms called PRIMARY CONSUMERS. These are the eaten by SECONDARY CONSUMERS, which are consumed by TERTIARY consumers. This is known as a FOOD CHAIN.
BIOME
a large naturally occurring community of flora and fauna occupying a major habitat, e.g. forest or tundra
Sample Food Chains
How is biomass measured?
Biomass can be measured in terms of the mass of carbon that an organism contains or the dry mass of its tissue per unit area per unit time
Dry mass is the mass of an organism with the water removed.
Water content of living organisms varies so dry mass is used to measure biomass rather than wet mass
To measure dry mass a sample of the organism is dried in an oven
The sample is weighed every day until it reaches constant mass. This is when all the water has been removed.
The mass of carbon is generally taken as 50% of the dry mass
Once you have the dry mass of the sample it can be scaled up to give the total dry mass (biomass) of the total population in the area being investigated (kgm-2)
Biomass changes over time so it is often quoted over a particular time period (kg m-2 yr-1).
Calorimetry
You can estimate the amount of chemical energy stored in biomass using a calorimeter.
The biomass is burned.
The heat energy released is used to heat a known volume of water.
The change in the water temperature is used to calculate the chemical energy in the dry biomass
Why is the container insulated?
Why is oxygen present in the sealed bomb?
Why is there a motorized stirrer?
To prevent heat losses to the atmosphere.
To ensure the biomass is fully burnt- released all it’s stored energy
To make sure the heat is evenly spread throughout the water
Primary Production
Gross primary production (GPP) is the total amount of chemical energy converted from light energy by plants in a given area in a given time.
Approximately 50% of the gross primary production is lost to the environment as heat when the plants respire. This is called Respiratory Loss (R)
The remaining chemical energy is called the net primary production (NPP)
Net Primary Production
This is the energy available to the plant for growth and reproduction- the energy stored in the plants biomass. It is also the energy available to organisms at the next stage of the food chain (the next trophic level)
This includes herbivores and decomposers
Net Production in Consumers
Consumers also store chemical energy in their biomass
They get their energy from ingesting plant material or animals that have eaten plant material
Not all the chemical energy stored in the consumers’ food is transferred to the next level.
Around 90% of the total available energy is lost in various ways
Energy losses
Explain the list of ways energy is lost in plants and animals – which refer to animals only
Not all energy absorbed –, some light misses the leaf or chloroplast, or is reflected off the surface animals may not consume the whole organism – eat leaves and not roots
Not all energy assimilated - in plants some wavelengths of light not absorbed, animals cannot digest cellulose(fibre)- herbivores lose more energy this way than carnivores
Respiratory loss (heat) – heat is by-product of metabolic reactions this hat energy is transferred to the environment animals move more than plants so respiratory losses are greater.
Homeotherms – maintaining a constant body temperature will also generally lose more energy than Poikilotherms.
Egestion – material that cannot be digested by animals passes through the digestive system and is removed in egestion. Typically cellulose(fibre)
Excretion - wates products of metabolic reaction eg: carbon dioxide are excreted animals cannot store protein, excess amino acids are deaminated ( have the –NH2) group removed . The nitrogen is excreted as urea CO(NH2)2 in urine from he kidneys
Death & decay – the dead bodies of plants and animals both contain biomass which is transferred to decomposers.
Net production in Consumers
N = I – (F + R)
N= Net Production
I= Chemical energy in ingested food
F= Chemical energy lost in Faeces and urine
R = Energy lost in respiration
Efficiency of Energy Transfer
As you move up the food chain from producers to consumers energy transfer usually becomes more efficient.
Typically between producer and consumer efficiency may be only 5-10%
Between consumers it may be 15-20%
Plants (producers contain more indigestible matter than animals (consumers)
Describe the reasons for the low efficiency of energy transfer through ecosystems (5 marks)
