Ecosystem Flashcards
An ecosystem can be visualised as a — of nature, where living organisms —- and also with the —- .
functional unit
interact among themselves
surrounding physical environment
Ecosystem varies greatly in — from a —- to a large forest or a sea.
size
small pond
Many ecologists regard the entire biosphere as a —-, as a composite of all
—- on Earth.
global ecosystem
local ecosystems
Since this system is too much — and —- to be studied at one time, it is convenient to divide it into two basic categories, namely the —- and —-.
big and complex
terrestrial and the aquatic
Forest, — and — are some examples of terrestrial ecosystems; pond, lake, —- , — and —are some examples of aquatic ecosystems.
grassland, desert
WETLAND, river and estuary
—- and —- may also be
considered as man-made ecosystems.
Crop fields and an aquarium
We will first look at the structure of the ecosystem, in order to appreciate the input (— ), —- (food chain/web, —–) and the output (— and —-).
productivity
transfer of energy
nutrient cycling
degradation and energy loss
We will also look at the
relationships – —, — and — – that are created as a result of these — within the system and their inter- relationship
cycles, chains, webs
energy flows
Various components of the environment- — and —.
abiotic and biotic
Individual biotic and abiotic factors affected — and —.
each other and their surrounding
Interaction of biotic and abiotic components result in a —-
physical structure
—- is characteristic for each type of ecosystem.
Physical structure (produced by interaction of biotic and abiotic factors)
— and —- of PLANT and ANIMAL species of an ecosystem gives its
—–.
Identification and enumeration
species composition
— distribution of different species occupying different levels is called —.
Vertical
stratification
For example, trees occupy —- or layer of a —,
— the second and —-
occupy the bottom layers.
top vertical strata, forest
shrubs
herbs and grasses
The components of the ecosystem are seen to function as a — when
you consider the following aspects: —- (4)
unit
(i) Productivity;
(ii) Decomposition;
(iii) Energy flow; and
(iv) Nutrient cycling.
To understand the — of an — ecosystem let us take a small pond as an example.
This is fairly a — and rather — example that explain even the — interactions that exist in an aquatic ecosystem.
ethos, aquatic
self-sustainable unit
simple
complex
A pond is a —- body in which all the above mentioned — basic components of an ecosystem are well exhibited
shallow water
four
The abiotic component in a small pond is the — with all the —- and —-substances and the —- at the bottom of the pond.
water
dissolved inorganic and organic
rich soil deposit
The —-, the cycle of —, — and other — conditions regulate the —- of the entire pond
solar input
temperature
day-length
climatic
rate of function
The — components of small pond include the —, some — and the —, — and —plants found at the edges.
autotrophic
phytoplankton, algae
floating, submerged and marginal
The consumers of small pond are represented by the —, the — and —- forms.
zooplankton
free swimming and bottom dwelling
The decomposers of small pond are the —, — and —- especially abundant in the — of the pond.
fungi, bacteria and flagellates
bottom
This pond system performs all the functions of any — and of the — as a whole, i.e., conversion of — material with the help of the —- of the sun by the autotrophs; — by heterotrophs; decomposition and — of the dead matter to release them back
for —-, these event are repeated over and over again.
ecosystem, biosphere
inorganic into organic
radiant energy
consumption of the autotrophs
mineralisation
reuse by the autotrophs
There is — movement of energy towards the — trophic levels and its —- and —- to the environment.
unidirectional
higher
dissipation and loss as heat
A — input of — is the basic requirement for any ecosystem to — and —.
constant
solar energy
function and sustain
— production is defined as the amount of — and –produced per unit — over a time period by PLANTS during —
Primary
biomass or organic matter
area
photosynthesis
Primary production is expressed in terms of —or —-.
weight (g/m^2) or
energy (kcal/m^2).
The —- is called productivity.
rate of biomass production
Productivity is expressed in terms of —- or —- to compare the productivity of different ecosystems.
g/ (m^2 year)
kcal/ (m^2 year)
Productivity can be divided into — and —-
gross primary productivity (GPP) and net primary productivity (NPP).
Gross primary productivity of an ecosystem is the rate of production of —- during — .
organic matter
photosynthesis
A considerable amount of GPP is utilised by plants
in — .
respiration
Gross primary productivity minus respiration losses (R), is the —–
net primary productivity (NPP).
GPP – ? = NPP
GPP – R = NPP
Net primary productivity is the —- for the consumption to heterotrophs (—)
available biomass
(herbiviores and decomposers)
Secondary productivity
is defined as the rate of formation of —–
new organic matter by consumers.
Primary productivity depends on the —- a
particular area. It also depends on a variety of —factors, availability of —and — of plants.
plant species inhabiting
environmental
nutrients
photosynthetic capacity
Therefore, —– varies in different types of ecosystems
1’ productivity
The — NET primary
productivity of the whole biosphere is approximately —- (—-) of organic matter.
annual
170 BILLION tons (dry weight)
Of the 170 billion tons of NPP, despite occupying about —- of the surface, the productivity of the oceans are only —
Rest of course, is on land.
70 percent
55 billion tons.
You may have heard of the earthworm being referred to as the —-. This is so because they help in the —- as well as in —
farmer’s ‘friend’
breakdown of complex organic matter
loosening of the soil.
Similarly, decomposers break down —- into inorganic substances like —-, — and —- and the process is called decomposition.
complex organic matter
carbon dioxide, water and nutrients
—– such as leaves, bark, flowers and dead remains of animals, including —, constitute —-
Dead plant remains
fecal matter
detritus
—– is the raw material for decomposition.
Detritus
The important steps in the process of
decomposition are —- (5)
fragmentation, leaching, catabolism, humification
mineralisation
Detritivores (Ex:—-) break down detritus into —.
This process is called —.
e.g., earthworm
smaller particles
fragmentation
By the process of —, —-nutrients go down into the —- and get precipitated as —-
leaching
water soluble inorganic
soil horizon
unavailable salts.
—– enzymes degrade detritus into simpler —-. This process is called as –.
Bacterial and fungal
inorganic substances
catabolism
It is important to note that all the above steps (frag, leach, cata) in decomposition —- on the detritus
operate simultaneously
Humification and
mineralisation occur during decomposition in the — .
soil
Humification leads to accumulation of a —- substance called —
dark coloured amorphous
humus
Humus is HIGHLY resistant to—- and undergoes decomposition
at —- rate.
highly resistant to microbial action
an extremely slow
Humus being — in nature it serves as a reservoir
of —.
colloidal
nutrients
The humus is further degraded by —- and release of — nutrients occur by the process known as —.
some microbes
inorganic
mineralisation
Decomposition is largely an —- requiring process.
oxygen-
The rate of decomposition is controlled by — of detritus and —factors.
chemical composition
climatic
In a particular climatic condition, decomposition rate is slower if detritus is rich in —- and quicker, if detritus is rich in —-
lignin and chitin,
nitrogen and water-soluble substances like sugars.
— and —- are the most important climatic factors that regulate decomposition through their effects on the —-
Temperature and soil moisture
activities of soil microbes.
—- and —- environment favour decomposition whereas — and —- inhibit decomposition resulting in —- materials.
Warm and moist
low temperature and anaerobiosis
build up of organic
Except for the —- ecosystem, — is the only source of energy for all ecosystems on Earth.
deep sea hydro-thermal
sun
Of the incident solar radiation —- of it is —- (PAR).
less than 50 per cent
photosynthetically active radiation
We know that —- and —-(autotrophs), fix —- to make food from simple —materials.
plants and photosynthetic bacteria
Sun’s radiant energy
inorganic
Plants capture only —- of the PAR and this small amount of energy —
2-10 per cent
sustains the entire living world.
So, it is very important to know how the — captured by plants flows through different organisms of an
ecosystem.
solar energy
All organisms are dependent for their food on — , either directly or indirectly.
producers
There is — of energy from the — to —- and then to consumers.
Is this in keeping with the first law of thermodynamics?
unidirectional flow
sun to producers
Further, ecosystems are not exempt from the — Law of— . They need a constant — to synthesise
the — they require, to counteract the —-
Second
thermodynamics
supply of energy
molecules
universal tendency toward
increasing disorderliness.
The — in the ecosystem are called producers.
green plant
In a terrestrial
ecosystem, major producers are — and —plants.
herbaceous and woody
Likewise, producers in an aquatic ecosystem are various species like —, — and —-
phytoplankton, algae and higher plants.
Starting from the plants (or —-) food chains or rather —- are
formed such that an animal feeds on a plant or on another animal and in
turn is food for another.
producers
webs
The food chain or web is formed because of —-.
this interdependency
— energy that is trapped into an organism remains in it —-.
No
for ever
The energy trapped by the producer, hence, is either —- or the —.
passed on to a consumer
organism dies
—- is the beginning of the detritus food chain/web
Death of organism
All —- depend on plants (directly or indirectly) for their —-
They are hence called —- and also —-
animals
food needs
consumers and also heterotrophs.
If the consumers feed on
the producers, the plants, they are called —, and if the animals eat other animals which in turn eat the plants (—-) they are called —-
Likewise, you could have tertiary consumers too.
primary consumers
or their produce
secondary consumers.
Obviously the primary consumers will be —.
herbivores
Some common herbivores are —-, — and —- in terrestrial ecosystem and —- in aquatic ecosystem
insects, birds and mammals
molluscs
The consumers that feed on these herbivores are —, or more correctly —- (though —consumers).
carnivores
primary carnivores
secondary
Those animals that depend on the primary carnivores for food are labelled —
secondary carnivores.
A simple — food chain (GFC) is depicted
below
grazing
Grass —> Goat —-> Man
The detritus food chain (DFC) begins with —-
dead organic matter
Detritus food chain is made up of decomposers which are —-, mainly – and —.
heterotrophic organisms
fungi and bacteria
Decomposers meet their — and — requirements by
degrading — organic matter or —. These are also known as —
energy and nutrient
dead
detritus
saprotrophs
Sapro means
to decompose
Decomposers secrete —- that breakdown — materials into simple, inorganic materials, which are subsequently —
digestive enzymes
dead and waste
absorbed by them.
In an aquatic ecosystem, — is the major — for energy flow.
GFC
conduit
As against this, in a terrestrial ecosystem, a much larger fraction of energy flows through the —- than —-.
detritus food chain than through the GFC
— food chain may be connected with the grazing food chain at some levels
Detritus
some of the organisms of — are — to the GFC animals, and in a natural
ecosystem, some animals like —-, —- etc., are omnivores.
DFC, prey
cockroaches, crows,
These —- of food chains make it a food web. How
would you classify human beings!
natural interconnection
Organisms occupy a place in the —- or in a
community according to their—- with other organisms.
natural surroundings
feeding relationship
Based on the —–, organisms occupy a specific place in the food chain that is known as their —–
source of their nutrition or food
trophic level.
—- belong to the first trophic level, herbivores (primary consumer) to the
second and carnivores (secondary consumer) to the third
Producers
1st trophic level/Producer (—) ex:
Plants
Grass, trees, phytoplankton
2nd trophic level/1’ consumer (—) ex:
Herbivore
zooplankton grasshopper, cow
third trophic level / 2’ consumer (—)
ex:
Carnivore
birds, fishes, wolf
4th trophic level / 3’ consumer (—)
ex:
Top carnivores
Man, Lion
The important point to note is that the amount of energy — at successive trophic levels.
decreases
When any organism —it is converted to detritus or —- that serves as —- source for decomposers.
dies
dead biomass
an energy
Organisms at each trophic level depend on those at the —- for their energy demands.
lower trophic level
Each trophic level has a certain —- at a particular
time called as the — crop.
mass of living material
standing
The —- is measured as the —- (biomass) or the number in a unit area.
standing crop
mass of living organisms
The biomass of a species is expressed in terms of — or —-
fresh or dry weight.
Measurement of biomass in terms of — is more accurate.
Why?
dry weight
The number of trophic levels in the —- is restricted as the transfer of energy follows —- law
grazing food chain
10 per cent
10% law:
only 10 per cent of the
— is transferred to each trophic level from the —-.
energy
lower trophic level
In nature, it is possible to have so many —– producer, herbivore, primary carnivore, secondary carnivore in the grazing food chain
Do you think there is any such limitation in a detritus food chain?
levels
The base of a —- is broad and it narrows towards the — . One gets a similar shape, whether you express the — or —- relationship between organisms at —- levels.
pyramid, apex
food or energy
different trophic
This, relationship of orgs in diff trophic levels is expressed in terms of
—, — or —-.
number, biomass or energy
The base of each pyramid represents the —- trophic level while the apex represents —–.
producers or the first
tertiary or top level consumer
The three types of —- that are usually studied are (a) pyramid of number; (b) pyramid of biomass and (c) pyramid of energy
ecological pyramids
Pyramid of numbers in a grassland ecosystem (—- pyramid)
Only —top-carnivores are
supported in an ecosystem based on production of nearly —- plants
upright
three, 6 millions
(based on figure given in ncert)
Pyramid of biomass (—- pyramid) shows a —- in biomass at higher trophic levels
mostly this is of grassland ig
upright
sharp decrease
—- pyramid of biomass-small standing crop of —supports large standing crop of —-
Inverted
phytoplankton
zooplankton
An ideal pyramid of energy, primary producers convert only —- in the sunlight available to them into —
1% of the energy
NPP
Any calculations of —, —- or —-, has to include —- at that trophic level.
energy content, biomass or numbers
all organisms
No generalisations we make will be true if we take only a —- at any trophic level into account.
few individuals
A given organism may occupy more than one trophic level SIMULTANEOUSLY.
T/F
True
One must remember that the trophic level represents a —-, not a —as such.
functional level
species
A given species may occupy more
than one trophic level in the —- and —-
for example,
a sparrow is a —- when it eats seeds, fruits, peas, and a —- when it eats insects and worms.
Can you work out
how many trophic levels human beings function at in a food chain?
same ecosystem at the same time;
primary consumer
secondary consumer
In —–, all the pyramids, of number, of energy and biomass are upright, i.e., —– are more in number and biomass than the herbivores, and herbivores are more in number and biomass
than the carnivores.
most ecosystems
producers
Also —- at a lower trophic level is ALWAYS more than at a — level
energy
There are exceptions to this generalisation:
If you were to count the
number of —- feeding on a —, the small birds dependent on it and the larger birds eating the smaller
draw what shape you will get
insects, big tree
The pyramid of —- in sea is generally —- because the biomass of —- far exceed —–
biomass
inverted
fishes far exceeds that of phytoplankton
Pyramid of — is always upright, can never be inverted, because when energy flows from a particular trophic level to the next trophic level,
some energy is —- at each step.
energy
always lost as heat
Each — in the energy
pyramid indicates the amount of energy present at each trophic level in a
given —– or —- per —
bar
time or annually per unit area.
However, there are certain limitations of —- such as :
1. it does not take into account the same species belonging to —- trophic levels.
2. It assumes a —-, something that almost
— in nature
3. it does not accommodate a —.
4. —- are not given any place in ecological pyramids even though
they play a — in the ecosystem.
ecological pyramids
two or more
simple food chain
never exists
food web
saprophytes
vital role
___ and____ are the 2 main structural features of ecosystem
Species composition and stratification
1’ productivity is the rate of —- or —— of the producers
capture of solar energy
biomass production
rate of capture of solar energy or total production of organic matter is —-
GPP
NPP is the remaining biomass or energy left after —–
utilization of producers
Secondary productivity is the rate of —- by the consumers.
assimilation of food energy
Decomposition involves —- processes, namely fragmentation of
detritus, leaching and catabolism.
three
The —- and —- of —- elements through the various components
of the ecosystem is called nutrient cycling;
nutrients are —- through this process
storage and movement of nutrient elements
repeatedly used
Nutrient cycling is of two types—— and —–
gaseous and sedimentary.
—- or —- is the reservoir for the gaseous type of cycle (—-), whereas —- is the reservoir for sedimentary type (—-)
Atmosphere or hydrosphere; carbon
Earth’s crust
phosphorus
Products of ecosystem processes are named as —–, e.g., purification of air and water by—.
ecosystem services
forests
