1. The document discusses population ecology concepts such as exponential and logistic growth models. Exponential growth occurs when resources are unlimited, while logistic growth tapers off as the population reaches the environment's carrying capacity.
2. It also covers population interactions like competition, predation, and parasitism. Competing species may undergo competitive exclusion or coexist through resource partitioning. Predation can control prey populations but also transfer energy between trophic levels.
3. Additional concepts covered include r/K selection strategies, survivorship curves, and different population growth models in species like bacteria and reindeer.
presentation contain different type of interactions, competition-intra and inter-specific, mechanism of competition-Exploitation and Interference, Mathematical models of Competition i.e. Hutchinson Ratio, Exponential Growth, Logistic Model, Lotka-Volterra Competition Model, Tilman's Resource Model, Results of Competition i.e. Range restriction, Competitive Displacement, Competitive Exclusion , Competitive Displacement Hypothesis, Ecological Niche, Evolution of new species, Factors Affecting Competition, Case studies
Ppt is made vailable for public for scientifc use.
Population ecology concept and its characteristics explained by using practical examples in a simple language. data is significant for competitive examinations
Ecological interactions chapter 3 class 11thUrfan Ali
INTRODUCTION
Ecological relationships describe the interactions between and among organisms within their environment. These interactions may have positive, negative, or neutral effects on either species' ability to survive and reproduce, or "fitness." By classifying these effects, ecologists have derived five major types of species interactions:
Predation, competition, mutualism, commensalism, parasitism and amensalism.
Mutualism describes an interaction that benefits both species. A well-known example exists in the mutualistic relationship between alga and fungus that form lichens. The photosynthesizing alga supplies the fungus with nutrients and gains protection in return. The relationship also allows lichen to colonize habitats inhospitable to either organism alone. In rare cases, mutualistic partners cheat. Some bees and birds receive food rewards without providing pollination services in exchange. These "nectar robbers" chew a hole at the base of the flower and miss contact with the reproductive structures.
Both species involved in the interaction are benefited. These interactions take place in three patterns:
Facultative mutualism – Species survive on their own under favorable conditions
Obligate mutualism – One species is dependent for survival on the other
Diffusive mutualism – One entity can live with multiple partners
These relationships have three purposes:
Defensive mutualism
Trophic mutualism
Dispersive mutualism
Mutualism describes an interaction that benefits both species. A well-known example exists in the mutualistic relationship between alga and fungus that form lichens. The photosynthesizing alga supplies the fungus with nutrients and gains protection in return. The relationship also allows lichen to colonize habitats inhospitable to either organism alone. In rare cases, mutualistic partners cheat. Some bees and birds receive food rewards without providing pollination services in exchange. These "nectar robbers" chew a hole at the base of the flower and miss contact with the reproductive structures.
Both species involved in the interaction are benefited. These interactions take place in three patterns:
Facultative mutualism – Species survive on their own under favorable conditions
Obligate mutualism – One species is dependent for survival on the other
Diffusive mutualism – One entity can live with multiple partners
These relationships have three purposes:
Defensive mutualism
Trophic mutualism
Dispersive mutualism
Population: Carrying Capacity and Limiting Factors in Natural systemsPaliNalu
What is earth's planetary carrying capacity for a modern, industrialized humanity with a properous standard of living for all? Explores limits and population limiting factors in real-world and biospheric systems.
presentation contain different type of interactions, competition-intra and inter-specific, mechanism of competition-Exploitation and Interference, Mathematical models of Competition i.e. Hutchinson Ratio, Exponential Growth, Logistic Model, Lotka-Volterra Competition Model, Tilman's Resource Model, Results of Competition i.e. Range restriction, Competitive Displacement, Competitive Exclusion , Competitive Displacement Hypothesis, Ecological Niche, Evolution of new species, Factors Affecting Competition, Case studies
Ppt is made vailable for public for scientifc use.
Population ecology concept and its characteristics explained by using practical examples in a simple language. data is significant for competitive examinations
Ecological interactions chapter 3 class 11thUrfan Ali
INTRODUCTION
Ecological relationships describe the interactions between and among organisms within their environment. These interactions may have positive, negative, or neutral effects on either species' ability to survive and reproduce, or "fitness." By classifying these effects, ecologists have derived five major types of species interactions:
Predation, competition, mutualism, commensalism, parasitism and amensalism.
Mutualism describes an interaction that benefits both species. A well-known example exists in the mutualistic relationship between alga and fungus that form lichens. The photosynthesizing alga supplies the fungus with nutrients and gains protection in return. The relationship also allows lichen to colonize habitats inhospitable to either organism alone. In rare cases, mutualistic partners cheat. Some bees and birds receive food rewards without providing pollination services in exchange. These "nectar robbers" chew a hole at the base of the flower and miss contact with the reproductive structures.
Both species involved in the interaction are benefited. These interactions take place in three patterns:
Facultative mutualism – Species survive on their own under favorable conditions
Obligate mutualism – One species is dependent for survival on the other
Diffusive mutualism – One entity can live with multiple partners
These relationships have three purposes:
Defensive mutualism
Trophic mutualism
Dispersive mutualism
Mutualism describes an interaction that benefits both species. A well-known example exists in the mutualistic relationship between alga and fungus that form lichens. The photosynthesizing alga supplies the fungus with nutrients and gains protection in return. The relationship also allows lichen to colonize habitats inhospitable to either organism alone. In rare cases, mutualistic partners cheat. Some bees and birds receive food rewards without providing pollination services in exchange. These "nectar robbers" chew a hole at the base of the flower and miss contact with the reproductive structures.
Both species involved in the interaction are benefited. These interactions take place in three patterns:
Facultative mutualism – Species survive on their own under favorable conditions
Obligate mutualism – One species is dependent for survival on the other
Diffusive mutualism – One entity can live with multiple partners
These relationships have three purposes:
Defensive mutualism
Trophic mutualism
Dispersive mutualism
Population: Carrying Capacity and Limiting Factors in Natural systemsPaliNalu
What is earth's planetary carrying capacity for a modern, industrialized humanity with a properous standard of living for all? Explores limits and population limiting factors in real-world and biospheric systems.
When a population of spotted salamanders in an area of vernal pools re.pdfaadyaenterprisesnoid
When a population of spotted salamanders in an area of vernal pools remains stable for many
years and the population has stabilized because of resource limits, then carrying capacity has
been reached. density dependence is not involved. predation has decreased. density independence
occurs. Exponential growth, when graphed, appears as a(n) straight line. "S" curve. "J" curve.
wavy line that goes up and down regularly. A biologist wants to estimate the size of a population
of turtles in a lake. She captures 18 turtles on her first visit to the lake, and marks their backs
with paint. A week later she returns to the lake and captures 18 turtles. Five of these 18 turtles
have paint on their backs, indicating that they are recaptured animals. Using this information,
biologist calculate the total salamander population in the lake is about 5 15 2 10 What pattern of
population growth corresponds to the principle of a carrying capacity? S-shaped bell-shaped J-
shaped a straight line To measure the population of lake trout, 4 Q individual trout were netted
and marked with a fin clip, then returned to the lake. The next week, the lake was netted again,
and out of the 480 lake trout that were caught, 5 had fin clips. Using the markrecapture estimate,
the lake trout population size could be closest to which of the following? 1680 408 50 320
Which of the following methods will provide information to an ecologist about both the size and
density of a population? mark and release quadrat life table mark and recapture Ants living in
acacia trees attack any predators of the tree. In return, the ants live protected in the thorns of the
tree and eat the nectar and protein-rich secretions of the tree. What term describes this
relationship? competition commensalism mutualism parasitism A community ecologist might
study: all the members of a single species that live together in a single geographic area. the
interactions among species living in a single area. the behavior of a species in its natural
environment. the rates of increase or decrease in the population size of individual species in
different environments. Which term best describes the relationship between leaf cutter ants and
the plants? Leaf Cutter Ants Jangle: How Nature Works Frnm Title: (3) Intobase. All rights
Reserved. Lengtn: 03:03 mutualism communism commensalism predation Cattle egrets hitch a
ride on domestic cows and eat insects that are stirred up by their activity. What term describes
this relationship? competition commensalism parasitism predation What role would an owl that
eats a seed-eating mouse perform in a food chain? secondary consumer producer primary
consumer tertiary consumer The North Atlantic Right Whale, Eubalaena glacialis, was called the
"right whale" because they were the best whale for early whalers to kill. They have long baleen
and lots of blubber and oil. When killed, they could be towed back to land for processing
because they float. They once numbered in the millions, but.
1)Inverse density dependent population regulationIn populace biolo.pdfapexjaipur
1)Inverse density dependent population regulation
In populace biology, thickness subordinate procedures happen when populace development rates
are directed by the thickness of a populace. Most thickness ward variables, which are organic in
nature (biotic), incorporate predation, between and intraspecific rivalry, gathering of waste, and
maladies, for example, those brought about by parasites. Typically, the denser a populace is, the
more prominent its death rate. For instance, amid intra-and interspecific rivalry, the regenerative
rates of the people will for the most part be lower, lessening their populace\'s rate of
development. What\'s more, low prey thickness expands the mortality of its predator since it has
more trouble finding its sustenance source.
A case of thickness ward direction is appeared with results from a study concentrating on the
goliath intestinal roundworm (Ascaris lumbricoides), a parasite of people and different warm
blooded animals. The information demonstrates that denser populaces of the parasite show bring
down fruitfulness: they contained less eggs . One conceivable clarification for this marvel was
that females would be littler in more thick populaces because of constrained assets so they would
have less eggs. This speculation was tried and refuted in a recent report which demonstrated that
female weight had no impact.
Many variables, regularly physical or substance in nature (abiotic), impact the mortality of a
populace paying little heed to its thickness. They incorporate climate, regular catastrophes, and
contamination. An individual deer might be slaughtered in a backwoods fire paying little heed to
what number of deer happen to be around there. Its odds of survival are the same whether the
populace thickness is high or low.
All things considered, circumstances, populace control is extremely entangled and thickness
reliant and autonomous variables can communicate. A thick populace that is decreased in a
thickness autonomous way by some natural factor(s) will have the capacity to recoup uniquely in
contrast to would a scanty populace. For instance, a populace of deer influenced by a cruel
winter will recoup speedier if there are more deer staying to imitate.
=====================================================
A populace cycle in zoology is a wonder where populaces rise and fall over an anticipated
timeframe. There are a few animal types where populace numbers have sensibly unsurprising
examples of progress despite the fact that the full purposes behind populace cycles is one of the
major unsolved environmental issues. There are various elements which impact populace
change, for example, accessibility of nourishment, predators, sicknesses and atmosphere
the term \"populace flow\" alludes to how the quantity of people in a populace changes after
some time. Scholars concentrate on the elements that influence populace elements since they are
keen on themes, for example, protection of jeopardized species (for inst.
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
This presentation explores a brief idea about the structural and functional attributes of nucleotides, the structure and function of genetic materials along with the impact of UV rays and pH upon them.
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
5. Exponential growth
When resource in the
habitat is unlimited,each
species has the ability
release fully its innate
potential to grow in
number,Darwin observed
while developing his theory
of natural selection then
the population grows in an
exponential or geometric
fashion
rise in population =r [ ln 𝑁] 𝑁𝑜
𝑁𝑡
= rt
r=b-d ln 𝑁 t – ln No = rt
at high birth rate and ln
𝑁𝑡
𝑁𝑜
= rt
at low mortality rate
𝑁𝑡
𝑁𝑜
=𝑒 𝑟𝑡
r- max therefore , Nt =No 𝑒 𝑟𝑡
Growth rate =
𝑑𝑁
𝑑𝑡
= rN as r is max, it is an
Therefore,
𝑑𝑁
𝑑𝑡
= rN exponential growth equation
or,
1
𝑁
ⅆ𝑁= r ⅆ𝑡
integrating both sides
𝑁𝑜
𝑁𝑡 1
𝑁
ⅆ𝑁 = r 0
𝑡
ⅆ𝑡
6. loge Nt = loge N0 + loge ert = loge N0 + rt
This equation indicates that loge N changes linearly in time; that is, a semilog plot of loge
N against t gives a straight line with a slope of r and a y-intercept of loge N0.
Setting N0 equal to 1 (i.e., a population initiated with a single organism), after one
generation, T, the number of organisms in the population is equal to the net reproductive
rate of that individual, or R0 . Substituting these values in the above equation:
loge R0 = loge 1 + rT
Since log 1 is zero, this equation reduces to loge R0 = rT or r = loge R0/T.
Another useful population parameter closely related to the net reproductive rate and the
intrinsic rate of increase is the so-called finite rate of increase, λ, defined as the rate of
increase per individual per unit time. The finite rate of increase λ is measured in the
same time units as the instantaneous rate of increase, and
r = loge λ or λ = er
In a population without age structure, l is thus identical with R0 [T equal to 1 in above
equations].
8. Logistic growth
A population growing in a
habitat with limited resources
show initially a lag phase
followed by phases of
acceleration and deceleration
and finally an asymptote,
when the population reaches
carrying capacity.
In nature, a given habitat has
enough resources to support a
maximum possible number
beyond which no further
growth is possible this limit is
what we call CARRYING
CAPACITY(K) for that species
in that habitat
12. SIGNIFICANCE OF K & SURVIVAL OF THE
FITTEST
When there is limited resources and population grows there exist a struggle for
survival. Darwin was convinced that interspecific competition is a potent force in
organic evolution.
IF COMPETITION OCCURS 2 POSSIBILTIES MAY EXIST
COMPETITIVE EXCLUSION-: It was explained by the scientist GAUSE. And gave
“Gausian competitive exclusion principle.”
RESOURCE PARTIONING
13. Gause principle & experiment
Gause's competitive exclusion principle, or sometimes called--Gause's Law, states
that “Two closely related species competing for the same resource cannot
coexist indefinitely and the competitively inferior one will be eliminated
eventually by the superior one” .
He placed Paramecium caudatum and Paramecium aurelia together in a test tube
with the same food supply. P. aurelia grew faster than P. caudatum and when grown
together, P. aurelia outmultiplied and eliminated P. caudatum. In nature, species
tend to have niches that are very specific and this reduces direct competition
allowing for more species to survive. For instance, in one tree, there may be seed
eating birds, fruit eating birds, birds feeding at the top, middle or bottom of the
tree. All of these niches reduce competition. Gause realized that a direct
competition between two different species cannot go on forever and one will
eventually perish.
16. A North Atlantic right whale with solitary
calf. Whale reproduction follows a K-
selection strategy, with few offspring,
long gestation, long parental care, and a
long period until sexual maturity
A litter of mice with their mother. The
reproduction of mice follows an r-
selection strategy, with many offspring,
short gestation, less parental care, and a
short time until sexual maturity.
17. Survivor ship curve
Type I survivorship curves are characterized by
high age-specific survival probability in early
and middle life, followed by a rapid decline in
survival in later life. They are typical of species
that produce few offspring but care for them
well, including humans and many other large
mammals.
Type II curves are an intermediate between
Types I and III, where roughly constant mortality
rate/survival probability is experienced
regardless of age. Some birds and some lizards
follow this pattern.
In Type III curves, the greatest mortality (lowest
age-specific survival) is experienced early in
life, with relatively low rates of death (high
probability of survival) for those surviving this
bottleneck. This type of curve is characteristic
of species that produce a large number of
offspring (see r/K selection theory). This
includes most marine invertebrates. For
example, oysters produce millions of eggs, but
most larvae die from predation or other causes;
those that survive long enough to produce a
hard shell live relatively long.
18. RESOURCE PARTIONING
It refers to the phenomenon in which species facing competition might evolve
mechanisms that promote coexistence rather than exclusion. Mac Arthur showed
that five closely related species of warblers living on the same tree were able to
avoid competition and coexist due to behavioural differences in their foraging
activities
Implications of resource portioning -:
1. Specialisation of morphology and behavior for different foods,such as the beeks of
birds which may be modified for picking up of insects , drilling holes,cracking nuts ,
tearing flesh and so on;
2. Verticle sepration(stratification) such as canopy dwellers and forest floor dwellers;
3. Horizontal sepration,such as the occupation of different micro habitat.
However , despite a tendency for each species its own particular niche , some direct
competition between species for available resources will still occur.
19.
20.
21.
22.
23.
24. Members of different population often interact in different ways with the
environment in which they live. These interactions between the two or several
species on based on three factors –
1. Nature of food and mode of obtaining it.
2. Kind of space to needed as shelter.
3. Habitat such as aggregation and breeding
There are mainly 3 types of interactions among the biotic community .
1. Negative (antagonistic/detrimental) interaction ,one species is harm while the
other is benefitted harmed and remain unaffected.
2. Positive(beneficial) interaction ,one species benefitted
3. Neutral interaction ,neither species is harmed nor benefitted
26. NEUTRALISM
It is an interaction in which a species is not affected by
the presence of other species in its niche . This lack of
interaction is known as neutralism
Eg – shrew , rabbit and rats inhabits the grassland but
none takes the other’s food. Shrew takes insects ,rats
feed on seeds and rabbits eat grasses.
27. PREDATION
ROLE OF PREDATOR
a) predators keep pray population under control. This is called
biological control.
b) Predators also keep in maintaining species diversity in a
community, by reducing the intensity of competition among
prey species
c) Besides acting as ‘conduits’ for energy transfer across trophic
level , predators play other important role. In absence of
predator species, prey species could achieve very high
population densities and lead to ecosystem instability
When certain exotic species are introduced in to a
geographical area ,they become invasive and start spreading
fast because the invaded land does not have its natural
predator.
If a predator is too efficient and over exploits its prey, then
the prey might become extinct and following it, the predator
will also become extinct due to lack of food.
30. THE PREY DEFENCE MECHANISMS
a) CAMOUFLAGE: It is the ability of an organism to blend
with their surroundings or background
EXAMPLES
METACHROSIS IN CHAMELEON
GRASSHOPPER(ARACTIA RECTIFOLIA)
PRAYING MANTIS(MANTIS RELIGIOSA){USES IN PREDATION}
STICK INSECT
LEAF INSECT
DEAD LEAF BUTTERFLY(PHYLLOCRANIA PARADOXA) CANNOT
BE DISTINGUISHED UNLESS AND UNTIL THEY SHOW
MOVEMENT
38. WARNING COLOURATION
Concealing from and colouration enables a species to avoid its natural predator . The
brightly coloured and highly poisonous dart frogs (Phyllobates bicolour, Dendrobates
pumillo) of the tropical rain forest of south America are easily recognized and avoided
by predators
39. b) MIMICRY: It is the resemblance of one species with
another in order to obtain advantage, especially ,against
predation .the species which is imitated is called MODEL.
While the animal which imitates is known as mimic or
mimetic. Model is either ferocious or distasteful to
predator
BATESIAN MIMICRY: In this mimicry the mimic is
defenseless .it has however resemblance to the
dangerous or unpalatable mode so that so that predator
usually does not prey upon it e.g.- viceroy butterfly
mimics monarch butterfly
MULLERIAN MIMICRY: in this mimicry there is the
resemblance to two animal species both ferocious/
unpalatable e.g.- bumble bee , honey bee ,yellow jacket
and paper wasp
42. The monarch butterfly is highly distasteful to its
predator because of special chemical present in its body
which is acquired by the butterfly by feeding on a
poisonous weed in its caterpillar stage
Some plants have thorns or spines for defense
mechanism e.g. cactus and acacia
Some plants produce highly poisonous chemicals like
cardiac glycosides ,nicotine , caffeine , quinine ,
strychnine opium etc.
45. The competition occurs due to limited resources between
closely related species
Some totally unrelated species could also compete for the
same resource e.g. in some shallow south American lakes
visiting flamingoes and resident fishes compete for the
zooplanktons
In interspecific competition the feeding efficiency of one
species might be reduced due to the interfering and inhibitory
presence of other species. Although the resources are
abundant
For example, after the introduction of goats in Galapagos
islands , the Abingdon tortoise became extinct within a
decade due to greater browsing efficiency of the goats
COMPETITIVE RELEASE refers to the phenomenon of a species
whose distribution is restricted to a small geographical area
because of the presence of a competitively superior species is
found to expand to distributional range directionally range
dramatically when the competing species is experimentally
removed
46.
47. CONNEL’S ELEGANT FIELD EXPERIMENT
Connell’s elegant field experiments showed that on the rocky sea coasts of Scotland,
the larger and competitively superior barnacle Balanus dominates the intertidal area,
and excludes the smaller barnacle Chathamalus from that zone
48. PARASITISM
Parasitic mode of life ensures free lodging and meals.
Some parasites are host-specific (one parasite has a single host) in such a way
that both host and parasite tend to co-evolve.
Parasitic adaptation
a) Loss of unnecessary sense organs.
b) Presence of adhesive organs or suckers to cling on to the host.
c) Loss of digestive system.
d) High reproductive capacity
Parasites having one or more intermediate host or vectors to facilitate
parasitisation of its primary host.
Liver fluke has two intermediate hosts (snail and a fish) to complete its live
cycle.
Effects on the host:
1. Parasite always harms the host.
2. They reduce the survival, growth and reproduction of the host.
3. Reduce its population density.
4. They make the host more vulnerable to the predators, by making it physically
weak.
49. Ectoparasite: feeds on the external surface of the
host.
Lice on human
Ticks on dog
Marine fish infested with copepods
Cuscuta parasitic plant grow on hedge plants.
50.
51.
52.
53.
54. Endoparasites: are those that live inside the host body at different sites.
Life cycle is more complex.
Morphological and anatomical features are greatly simplified.
Highly developed reproductive system.
E.g.
1. Taenia solium(pork tape worm)
2. Schistosoma(fluke)
3. Plamodium (malarial parasite)
55.
56.
57.
58. Brood parasitism:
Special type of parasitism found in birds.
The parasitic birds lay its eggs in the nest of its host and
let the host incubate them.
The egg of the host is very similar with the egg of the
host.
Cuckoo lays eggs in the nest of the crow.
59. COMMENSALISM
This is the interaction in which one species benefits and
the other is neither benefited nor harmed.
EXAMPLES
Orchids growing as an epiphyte on a mango branch.
Clown fish living among tentacles of sea anemone.
Barnacles on back of whales.
Cattle Egret and grazing cattle
60.
61.
62.
63.
64. AMENSALISM
Amensalism is referred as the interaction between two
different species ,in which one is harmed and other is
neither harmed nor benefitted
E.g. , the mould penicillium secrete penicillin which
kills bacteria but the mould is unaffected
65. MUTUALISM
Mutualism is referred to as the interspecific interaction in which both the
interacting species are benefited
Some examples of mutualism
a. LICHENS represent close association between fungus and photosynthetic algae or
cyanobacteria where the fungus helps in absorption of nutrients and provide
protection while algae or cyanobacteria prepress the food
66. b) MYCORRHIZAE are close mutual association between fungi and roots of higher
plants , where fungi helps the plant for absorption of nutrients while the plant
provides food for fungus
67. Plant need help from animals for pollination and dispersal of seeds . In return ,
plant provide nectar pollen and fruits from pollinators.
E.g.- Blastophaga (wasp) uses the fruit not only as an oviposition site but uses the
developing seeds within fruit for nourishment . The wasp pollinates the fig
inflorescence . While searching for suitable egg –laying site in return fig provides
the wasp some seeds for nourishment
68. Mediterranean orchid Ophrys employs ‘sexual deceit’ to
get pollinated by the species of bee . One petal of this
flower bears an uncanny resembelence to the female bee
in size ,colours and marking
The male bee is attracted to what It perceives s a female
and pseudocopulate with the flower . During the process ,
the pollen is dusted from the flower. When the small bee
pseudocopulates with another flower , it transfers pollen
to it and pollinates another flower