3. I would like to express my special thanks of gratitude
to my biology teacher Mr. Arun Kumar sir as well as
our principal sir who gave us this golden opportunity
to do this wonderful project on the topic
“PREDATION” which also helped me in doing a lot
of Research and I came to know about so many new
things I am really thankful to them. Secondly, I
would also like to thank my parents and friends who
helped me a lot in finalizing this project within the
limited time frame
ACKNOWLEDGEMENT
4. • Certificate
• Acknowledgement
• Introduction
• Types of predation
• Importance of Predation
• Prey defences
• Conclusion
• Bibliography
INDEX
5. INTRODUCTION
Ultimately,the source of energy for all life originatesfrom the sun. Plants
utilizethe sun's energy, animals eat plants and utilizethe plants' energy,
and some animalseat other animals and utilizetheir energy. The food chain
is a cycle of predation, and although it is necessary for life to exist, it has to
have limits.Prey develop defenses against their predators,and predators
striveto overcome such obstacles.The balance between survival of prey
and predator is part of the reason that our ecosystem is so diverse.
It is easy to think of predation in the context of common sense. Predator
eatsprey. However,ecologically,predation is defined as any interaction
betweentwoorganisms that results in a flow of energy between them. This
definitionis applicable to both plants and animals.There are four
commonlyrecognized types of predation: (1) carnivory, (2) herbivory,
(3) parasitism,and (4) mutualism.Each type of predation can by
categorizedbased on whether or not it results in the death of the prey.
Carnivoryis lethal to the prey, while herbivory and parasitismmay or may
not be lethal to the prey. Mutualismis not lethalto either predator or prey
but, rather,benefits both organisms.
INTRODUCTION
6. There are two major types of Predation :
Carnivory - Carnivory takes place when a predator
consumes meat rather than plants and consequently
kills its prey.
Herbivory - Herbivory is a form of predation in
which the prey organism is a plant.
TYPES OF PREDATION
7. Carnivory is usually the first type of predation that comes
to mind when thinking about relationships between predator
and prey. Carnivory takes
place when a predator
consumes meat rather than
plants and consequently
kills its prey. Organisms
that eat meat are
accordingly called
carnivores. Some
types of carnivores do not
need to eat meat in order to survive but do so
anyway. Obligatory carnivores, on the other hand, cannot
survive without meat in their diet. Hyper carnivores are an
extreme example of obligatory carnivores and are able to
eat only meat due to restricted digestive capabilities. Even
though we sometimes associate carnivores with larger
animals, carnivorous habits can occur in plants and fungi
that feed on insects or microscopic invertebrates.
Carnivory
A carnivorous plant has evolved
mechanisms of attracting, trapping, and
consuming insects
8. Herbivory is a type of predation in which animals/organismsconsume
autotrophssuch as plants,algae, and photosynthesizingbacteria.Herbivory
is a term commonly used to describe the consuming of plants by animals.
Herbivorescan be divided into two main
groups: monophagous and polyphagous.
Monophagous herbivores are organisms
that exclusively eat one plant species,
and the survival of these organisms is
dependent on the survival of the
primaryfood source. Also,monophagous
herbivores are immune to the plant's
defenses,both mechanical and
chemical.For example, the Monarch Butterflythat feeds on milkweed is
immuneto itstoxic defenses. Other examples of monophagous herbivores
are the Giant Panda, whose diet consists of 99% bamboo, and Koala Bears,
who feed on Eucalyptusleaves. Most herbivores are polyphagous and feed
on more than one type of plant, but herbivores can be further divided into
several subgroups, which are frugivores, meaning they eat primarily
fruit,folivores,which eat leaves, and nectarivores, which feed on nectar.
Herbivorycan include consuming roots and/or tubers below the ground as
wellas the portion of the plant that is above-ground.
Herbivory
The Koala Phascolarctos cinereus is an
herbivore.
9. Besides acting as ‘conduits’ for energy transfer across trophic levels,
predator plays other important roles. They keep prey populations
under control. But for predators, prey species could achieve very
high population densities and cause ecosystem instability.
When a certain exotic species are introduced into a geographical
area, they become invasive and start spreading fast because the
invaded land does not have its natural predators. The prickly pear
cactus introduced into Australia in early 1920’s caused havoc by
spreading rapidly into millions of hectares of rangeland. Finally, the
invasive cactus was brought under control only after a cactus-
feeding predator (a moth) from its natural habitat was introduced
into the country. Biological control methods adopted in agricultural
pest control are based on the ability of the predator to regulate prey
population.
Importance of Predators
Prickly pear cactus attacked by moth
10. Predatorsalso help in maintaining speciesdiversityin a
community, by reducing the intensityof the competition
among competing prey species.In the rocky intertidal
communitiesof the American PacificCoast the starfish
Pisasteris an important predator.
In a field experiment, when all the starfishwere removed
from an enclosed intertidalarea, more than 10 speciesof
invertebratesbecame extinct within a year, because of
interspecificcompetition.
(a) Pisaster predation maintains a diverse community. (b) removal of
Pisaster allows mussels to dominate, and reduces species diversity.
11. Predation can result in the development of anti-predationstrategiesby prey
populations.Consequently,predator populations develop their own strategiesto
overcomeprey defenses. This phenomenon, known as the red-queen theory,
plays an importantrole in evolution and predator-prey interactions.
If a predator is too efficientand overexploits its prey, then the prey might
become extinct and followingit, the predator willalso become extinct for lack
of food. This is the reason why predators in nature are ‘prudent’.
Prey species have evolved various defenses to lessen the impact of predation.
Some species of insectsand frogs are cryptically-coloured(camouflaged)to
avoid being detectedeasily by the predators.
PREY DEFENSES
Some butterflies protect themselves through camouflage—
by folding up their wings, they reveal the undersides and blend
in with their surroundings. Through this strategy, known as
crypsis, they become nearly invisible to predators. Bright colors
and distinctive wing patterns can, however, be advantageous.
12. Some are poisonous and therefore avoided by the
predators. The Monarch butterfly is highly distasteful
to its predator (bird) because of a special chemical
present in its body.
Interestingly, the butterfly acquires this chemical
during its caterpillar stage by feeding on a poisonous
weed.
13. For plants, herbivores are the predators. Nearly 25 per cent of all insects
are known to be phytophagous (feeding on plant sap and other parts of
plants). The problem is particularly severe for plants because, unlike
animals, they cannot run away from their predators. Plants therefore
have evolved an astonishing variety of morphological and chemical
defenses against herbivores.
Thorns (Acacia, Cactus) are the most common morphological means of
defence. Many plants produce and store chemicals that make the
herbivore sick when they are eaten, inhibit feeding or digestion, disrupt
its reproduction or even kill it. You must have seen the weed
Calotropis growing in abandoned fields. The plant produces highly
poisonous cardiac glycosides and that is why you never see any cattle
or goats browsing on this plant. A wide variety of chemical substances
that we extract from plants on a commercial scale (nicotine, caffeine,
quinine, strychnine, opium, etc.,) are produced by them actually as
defences against grazers and browsers.
14. Predation is a classic species interaction that has been
investigated for a very long time. Conceptually,
predation is a +/− interaction that benefits one side,
the predator, and harms the other side, the prey. In
brutal reality, of course, prey is often not just
“harmed” but killed. That depends on the type of
predator: True predators are those that typically kill
their prey, whereas grazers remove parts of their prey
but do not usually kill them
CONCLUSION