RELATIONSHIP IN NATURE:
ACTIVITIES OF MAN
Lara, Anne Marie Lorraine
1st Semester, SY 2013-2014
Prof. Rosalie Anne Mangahas
RELATIONSHIP IN NATURE – ACTIVITIES OF MAN
Biological interactions can involve individuals of the same species (intraspecific
interactions) or individuals of different species (interspecific interactions). These can be
further classified by either the mechanism of the interaction or the strength, duration and
direction of their effects. Species may interact once in a generation (e.g. pollination) or
live completely within another (e.g. endosymbiosis). Effects range from consumption of
another individual (predation, herbivory, or cannibalism) to mutual benefit (mutualism).
Interactions need not be direct; individuals may affect each other indirectly through
intermediaries such as shared resources or common enemies.
Mutualism is a type of symbiosis. Symbiosis is a broad category, defined to
include relationships that are mutualistic, parasitic, or commensal. Mutualism is only
Mutualism is any relationship between individuals of different species where both
individuals benefit. A mutualistic relationship is when two organisms of different species
"work together," each benefiting from the relationship.
IMPORTANCE OF MUTUALISM
Coevolution. Organisms in a mutualistic relationship evolved together. Each was
part of the other's environment, so as they adapted to their environment, they "made
use of" each other in a way that benefited both. Mutualism is thought to have driven the
evolution of much of the biological diversity we see, such as flower forms (important for
pollination mutualisms) and co-evolution between groups of species.
Mutualism plays a key part in ecology. For example, mutualistic interactions are
vital for terrestrial ecosystem function as more than 48% of land plants rely on
mycorrhizal relationships with fungi to provide them with inorganic compounds and trace
Biodiversity Sustainability. A large percentage of herbivores have mutualistic gut
fauna that help them digest plant matter, which is more difficult to digest than animal
prey. This gut fauna is made up of cellulose-digesting protozoans or bacteria living in
the herbivores' intestines. Coral reefs are the result of mutualisms between coral
organisms and various types of algae that live inside them. Most land plants and land
ecosystems rely on mutualisms between the plants, which fix carbon from the air, and
mycorrhyzal fungi, which help in extracting water and minerals from the ground.
EXAMPLES OF MUTUALISM
1. Ungulates (such as Bovines) and bacteria within their intestines. The
ungulates benefit from the cellulase produced by the bacteria, which facilitates
digestion; the bacteria benefit from having a stable supply of nutrients in the host
2. Bee and flower. Bees fly from flower to flower gathering nectar, which they
make into food, benefiting the bees. When they land in a flower, the bees get
some pollen on their hairy bodies, and when they land in the next flower, some of
the pollen from the first one rubs off, pollinating* the plant. This benefits the
plants. In this mutualistic relationship, the bees get to eat, and the flowering
plants get to reproduce.
* Pollination is when the pollen from one flower gets into another flower, allowing
the plants to reproduce.
3. Bacteria and human. A certain kind of bacteria lives in the intestines of humans
and many other animals. The human cannot digest all of the food that it eats. The
bacteria eat the food that the human cannot digest and partially digest it, allowing
the human to finish the job. The bacteria benefit by getting food, and the human
benefits by being able to digest the food it eats.
4. Oxpecker (a kind of bird) and rhinoceros or zebra. Oxpeckers land on rhinos
or zebras and eat ticks and other parasites that live on their skin. The oxpeckers
get food and the beasts get pest control. Also, when there is danger, the
oxpeckers fly upward and scream a warning, which helps the symbiont (a name
for the other partner in a relationship).
5. Ocellaris clownfish and Ritteri sea anemones. Ocellaris clownfish dwell
among the tentacles of Ritteri sea anemones. The territorial fish protects the
anemone from anemone-eating fish, and in turn the stinging tentacles of the
anemone protect the clownfish from its predators. Special mucus on the
clownfish protects it from the stinging tentacles.
6. Goby fish and shrimp. Goby fish sometimes lives together with a shrimp. The
shrimp digs and cleans up a burrow in the sand in which both the shrimp and the
goby fish live. The shrimp is almost blind, leaving it vulnerable to predators when
above ground. In case of danger the goby fish touches the shrimp with its tail to
warn it. When that happens, both the shrimp and goby fish quickly retreat into the
TYPES OF MUTUALISM
It is common to categorize mutualisms according to the closeness of the
association, using terms such as obligate and facultative so as to measure the exact
fitness benefit to the individuals in a mutualistic relationship.
1. Facultative Mutualism
Both species benefit from the interaction but each can live without the other,
a. Some kinds of plants produce seeds by self-pollination if they fail to be
visited by their usual pollinators, and the pollinators may do just as well with
nectar from other sources.
b. Many ants are found in the vicinity of aphids. The ants feed on the sugary
fluid released by the aphids, and the aphids are protected by the ants.
c. Small fish of several families, including a wrasse, feed on small organisms
and parasites on the bodies of larger fish. These cleaner or barber fish in
this manner, and the larger fish are relieved of unwelcome guests on their
2. Obligate Mutualism
Neither one of two interacting species can survive for long without the
a. Yucca moth and yucca plant. This moth obtains pollen only from the yucca
plant; even its larval form dines only on yucca seeds. The yucca plant
depends exclusively on this one moth pollinator. Hence, the moth’s private
energy source, available throughout its lifetime, helps assure reproductive
success. At the same time, the moth helps assure reproductive success for
the plant; the pollen is carried exactly where it must go instead of being
randomly spread about by a less picky pollinator that visits several plant
b. Lichens are plants made up of a fungus and an alga living in close
association. They are usually found on rocks and tree trunks. The fungus is
attached to the substratum by fungal treads. These fungal treads help to
absorb inorganic substances which are then used by the alga during
photosynthesis (when organic compounds are made). The fungus obtains
organic substances manufactured by the alga;
c. Bees and birds visit flowers in search of pollen and nectar. In the process
flowers are pollinated.
Commensalism describes a relationship between two living organisms where one
benefits and the other is not significantly harmed or helped. Commensalism derives
from the English word commensal, meaning "eating at the same table" in human social
interaction, which in turn comes through French from the Medieval Latin commensalis,
meaning "sharing a table", from the prefix com-, meaning "together", and mensa,
meaning "table" or "meal". Originally, the term was used to describe the use of waste
food by second animals, like the carcass eaters that follow hunting animals, but wait
until they have finished their meal.
Commensalism is harder to demonstrate than parasitism and mutualism, for it is
easier to show a single instance whereby the host is affected, than it is to prove or
disprove that possibility. Usually, a detailed investigation will show that the host indeed
has become affected by the relationship.
EXAMPLES OF COMMENSALISM
1. Cattle egrets foraging in fields among cattle or other livestock. As cattle,
horses and other livestock graze on the field, they cause movements that stir up
various insects. As the insects are stirred up, the cattle egrets following the
livestock catch and feed upon them. The egrets benefit from this relationship
because the livestock have helped them find their meals, while the livestock are
typically unaffected by it.
2. Birds following army ant raids on a forest floor. As the army ant colony
travels on the forest floor, they stir up various flying insect species. As the insects
flee from the army ants, the birds following the ants catch the fleeing insects. In
this way, the army ants and the birds are in a commensalistic relationship
because the birds benefit while the army ants are unaffected.
3. Kol-bal jackals and tigers. In India, lone golden jackals expelled from their pack
have been known to form commensal relationships with tigers. These solitary
jackals, known as kol-bahl, will attach themselves to a particular tiger, trailing it at
a safe distance in order to feed on the big cat's kills. A kol-bahl will even alert a
tiger to a kill with a loud pheal (thereby straying into mutualism). Tigers have
been known to tolerate these jackals: one report describes how a jackal
confidently walked in and out between three tigers walking together a few feet
away from each other. Tigers will however kill jackals on occasion: the now
extinct tigers of the Amu Darya region were known to eat jackals frequently.
TYPES OF COMMENSALISM
It involves one species using the body or a body cavity of another organism
as a platform or a living space while the host organism neither benefits nor is
a. Between barnacles and whales. Barnacles are normally sessile or non-
moving sea creatures. They rely on currents to bring food past them in order
to eat. However, some barnacles have attached themselves to the sides of
various sea lives, such as whales, in order to have a more advantageous
position in life. These barnacles benefit by receiving transportation all over
the ocean which exposes them to more currents and feeding opportunities
than they would normally experience. The whale neither benefits nor is
harmed by the barnacles.
This is a form of commensalism that occurs when one species
unintentionally creates a home for another species through one of its normal life
a. A species of woodpecker known as the Gila woodpecker creates holes in
the surface of the Saguaro cacti as they search for food and water in
deserts. These abandoned holes are then used as homes and nesting sites
by various species of birds and small mammals.
b. Hermit crabs using gastropod shells to protect their bodies and spiders
building their webs on plants.
This takes place when one organism attaches to another organism
specifically for the purpose of gaining transportation.
a. Plants benefit from phoresy commensalism when they have burs or seeds
that attach to the fur of animals as they pass by. The seeds are later
dropped or scratched off in another location, providing a means of seed
dispersal for the plants rather than relying on the wind.
This is the opposite of commensalism, wherein the other is harmed by the
presence of the other.
a. The bread mold penicillium is a common example; penicillium secrete
penicillin, a chemical that kills bacteria.
b. Black walnut tree (Juglans nigra) secrete juglone, an allelochemical that
harms or kills some species of neighboring plants.
c. A third example is when sheep or cattle make trails by trampling on grass,
thereby destroying a food source.
A parasitic relationship is one in which one organism, the parasite, lives off of
another organism, the host, harming it and possibly causing death. The parasite lives on
or in the body of the host.
Usually, although parasites harm their hosts, it is in the parasite's best interest
not to kill the host, because it relies on the host's body and body functions, such as
digestion or blood circulation, to live.
Some parasitic animals attack plants. Aphids are insects that eat the sap from
the plants on which they live. Parasitic plants and fungi can attack animals. A fungus
causes lumpy jaw, a disease that injures the jaws of cattle and hogs. There are also
parasitic plants and fungi that attack other plants and fungi. A parasitic fungus causes
wheat rust and the downy mildew fungus attacks fruit and vegetables. Some scientists
say that one-celled bacteria and viruses that live in animals and harm them, such as
those that cause the common cold, are parasites as well. However, they are still
considered different from other parasites. Many types of parasites carry and transmit
disease. Lyme disease is trasmitted by deer ticks.
A parasite and its host evolve together. The parasite adapts to its environment by
living in and using the host in ways that harm it. Hosts also develop ways of getting rid
of or protecting themselves from parasites. For example, they can scratch away ticks.
Some hosts also build a symbiotic relationship with another organism that helps to get
rid of the parasite. Ladybugs live on plants, eating the aphids and benefiting by getting
food, while the plant benefits by being rid of the aphids.
KINDS OF PARASITES
1. Animal parasites: Resulting with lice on humans, mosquitos on humans, leech
on mammals, round worms/nematodes in most vertebrates, fasciola in humans,
tapeworms in cow, ticks on dogs, fleas on dogs, barnacles on crabs.
2. Bacterial parasites: Resulting to Bacterial infections, such as sore throat, E coli
3. Worm infestations: Resulting to having Hookworms or tapeworms.
4. Protist parasites: Resulting to protist infections, such as amoebic dysentery.
5. Viral Parasites: Resulting to viruses such as that causes the flu or AIDS
6. Plant parasites: Mistletoe is plant parasite.
TYPES OF PARASITES
1. Ectoparasites – parasites that lives outside the host’s body (e.g. some mites)
2. Endoparasites – parasites that lives inside the host’s body (e.g. hookworms that
live in the host’s gut)
3. Parasitoids – (or necrotroph) parasites that use another organism’s tissue for
their own nutritional benefit until the host dies from loss of needed tissues or
4. Biotrophic – parasitest that cannot survive in a dead host and therefore keep
their hosts alive (e.g. many viruses)
5. Social parasites – parasites that take advantage of interactions between
members of a social host species to their detriment
6. Epiparasites – (or hyperparasitoids) parasites that feeds on another parasite
EXAMPLES OF PARASITISM
1. Tapeworms are segmented flatworms that attach themselves to the insides of the
intestines of animals such as cows, pigs, and humans. They get food by eating
the host's partly digested food, depriving the host of nutrients.
2. Fleas harm their hosts, such as dogs, by biting their skin, sucking their blood,
and causing them to itch. The fleas, in turn, get food and a warm home.
3. Barnacles, which live on the bodies of whales, do not seriously harm their hosts,
but they do itch and are annoying.
In ecology, predation describes a biological interaction where a predator (an
animal that is hunting) feeds on its prey (the animal that is attacked). Predators may or
may not kill their prey prior to feeding on them, but the act of predation often results in
the death of its prey and the eventual absorption of the prey's tissue through
A predator is an organism that eats another organism. The prey is the organism
which the predator eats. Some examples of predator and prey are lion and zebra, bear
and fish, and fox and rabbit. The words "predator" and "prey" are almost always used to
mean only animals that eat animals, but the same concept also applies to plants: Bear
and berry, rabbit and lettuce, grasshopper and leaf.
Predator and prey evolve together. The prey is part of the predator's
environment, and the predator dies if it does not get food, so it evolves whatever is
necessary in order to eat the prey: speed, stealth, camouflage (to hide while
approaching the prey), a good sense of smell, sight, or hearing (to find the prey),
immunity to the prey's poison, poison (to kill the prey) the right kind of mouth parts or
digestive system, etc. Likewise, the predator is part of the prey's environment, and the
prey dies if it is eaten by the predator, so it evolves whatever is necessary to avoid
being eaten: speed, camouflage (to hide from the predator), a good sense of smell,
sight, or hearing (to detect the predator), thorns, poison (to spray when approached or
TYPES OF PREDATION
1. Herbivory – consumption of plant or algal tissue
2. Carnivory – consumption of animal tissue
3. Mycophagy – consumption of parts of fungi
4. Omnivory – consumption of both plant and animal tissues
5. Detritivory – consumption of dead organic material
EXAMPLES OF PREDATION
The fastest lions are able to catch food and eat, so they survive and reproduce,
and gradually, faster lions make up more and more of the population. The fastest
zebras are able to escape the lions, so they survive and reproduce, and gradually,
faster zebras make up more and more of the population. An important thing to realize is
that as both organisms become faster to adapt to their environments, their relationship
remains the same: because they are both getting faster, neither gets faster in relation to
the other. This is true in all predator-prey relationships.
Another example of predator-prey evolution is that of the Galapagos tortoise.
Galapagos tortoises eat the branches of the cactus plants that grow on the Galapagos
Islands. On one of the islands, where long-necked tortoises live, the branches are
higher off the ground. On another island, where short-necked tortoises live, the
branches are lower down. The cactuses, the prey, may have evolved high branches so
that the tortoises, the predators, can't reach them.
However, not just in this case but in any case of co-evolution and evolution, that
there is always more than one cause that forces an organism to adapt, and though it is
likely that the higher branches are to avoid the tortoises, it is also possible that it was a
different cause, such as the sun, the ocean, or a different organism.
Competition is a rivalry of two or more parties over something. Competition is an
interaction between individuals brought about by a shared requirement for a resource in
limited supply (e.g. food, space, shelter, mate, ecological status, etc.), leading to a
reduction in survivorship, growth, and/or reproduction of the individuals concerned.
Specific Ways that Individuals May Compete
1. Exploitation--depleting resources
2. Pre-emptive--using space
3. Overgrowth--species growing over another and depriving the other of light
4. Chemical--production of toxins
5. Territorial--behavior or fighting in defense of space
6. Encounter--transient interactions directly over a specific resource
KINDS OF COMPETITION
1. Interspecific Competition
This is a competition where individuals of one species suffer a reduction in
fecundity, survivorship, or growth as a result of resource (e.g. food or nutrients,
space, mates, nesting sites) exploitation or interference by individuals of a
second species. Survival is the key in this type of situation.
2. Intraspecific Competition
This competition is the struggle between members of a population for
Types of Intraspecific Competition
a. Adapted or programmed intraspecific competition results from
aggressive social behavior such as dominance hierarchies and
territoriality. Here only certain individuals high in the peck-order, or
holding territories, succeed in breeding. This is sometimes
called contest competition because it involves aggressive contests
between competing individuals.
b. Unadapted or incidental intraspecific competition results from the
accidental interaction between individual organisms utilizing the same
resources, for resources used by one are unavailable to others. This is
sometimes called scramble competition because everybody is involved
in a mad scramble for the scarce resources.
TYPES OF COMPETITION
1. Interference Competition
This occurs directly between individuals via aggression etc. when the
individuals interfere with foraging, survival, reproduction of others, or by directly
preventing their physical establishment in a portion of the habitat.
Ex: Male-male competition in red deer during rut is an example of interference
competition within a species.
2. Exploitation Competition
This occurs indirectly through a common limiting resource which acts as
an intermediate. For example, the use of the resource(s) depletes the amount
available to others, or they compete for space.
Ex: The older, taller trees create a canopy effectively absorbing the available
light. Thus, the younger, smaller trees do not have access to that resource and
are less likely to survive.
3. Apparent Competition
This occurs indirectly between two species which are both preyed upon by
the same predator.
Ex: An example of this competition is the competition between nettle aphids (prey
A) and grass aphids (prey B) in the area. Both of these organisms are prey to
Coccinellidae (predator). The increase in the population of grass aphids (prey B)
attracted more Coccinellidae (predator) in the area, resulting in increased
predation of Coccinellidae of nettle aphids (prey A).
Is often referred to as cryptic coloration
Is an important defensive strategy utilized by many organisms in nature
Structural adaptation that enables species to blend colors and patterns with their
surroundings to avoid detection by predators
a. Praying mantises sit in flowers of a similar color and ambush visiting insects.
b. White ermines (a type of weasel) and snowy owls hunt in snow covered areas.
Is commonly known as warning coloration.
Is a strategy used by some animals to alert potential predators of their presence with
bold colors with patters to promote avoidance.
a. Black-and-white stripes of the skunk
b. Bright orange of the monarch butterfly
c. Yellow-and-black coloration of many bees and wasps and some snakes.
The resemblance of one organism to another or to an object in its surroundings for
concealment or protection from predators.
Types of Mimicry
1. Aggressive mimicry – A form of mimicry in which a predator (the mimic)
closely resembles another organism (the model) that is attractive to a third
organism (the dupe) on which the mimic preys.
a. The bright leaves of the venus flytrap (Dionaea muscipula) attract
insects in the same way as flowers.
b. The Alligator Snapping Turtle uses its tongue to lure fish. The Alligator
Snapping Turtle (Macrochelys temminckii) is a well-camouflaged
ambush predator. Its tongue bears a conspicuous pink extension that
resembles a worm and can be wriggled around; fish that try to eat the
"worm" are themselves eaten by the turtle.
2. Batesian mimicry – A form of protective mimicry in which an unprotected
species (the mimic) closely resembles an unpalatable or harmful species (the
model), and therefore is similarly avoided by predators.
a. The Syrphid fly mimics the colors and markings of honey bees.
b. The Monarch would be the model and the Viceroy the mimic. Monarch
is described as being distasteful (from feeding on milkweed) and is
avoided by avian predators and the Viceroy, not closely related to the
Monarch, is is described as not being distasteful but is also avoided by
3. Müllerian mimicry – A form of protective mimicry in which two or more
poisonous or unpalatable species closely resemble each other and are
therefore avoided equally by all their natural predators.
a. Poison dart frogs of South America and Madagascar. Poison frogs of
the Dendrobate genus are known to secrete poison onto their skin as a
means of protection. The poison is produced and derived from insects
consumed in their native habitats. Most of them are marvelously
colored with bright yellow, green, and blue, and some have elaborate
striped patterns. All of this coloration serves as a warning sign for any
b. H. erato and H. melpomene are two different species of butterflies that
exhibit Mullerian mimicry. Both of them have evolved to have mostly
black bodies and wings, but they have a similar pattern of red-orange
dots and markings on their wings. Both of these species of butterflies
have a taste that is very undesirable to predators. Their bad taste is
derived from the food that their caterpillar form eats before they
undergo metamorphosis and become butterflies. Since both of these
species have the same bad taste, most predators will need to only try
one to learn to avoid the other. If you have ever eaten at a restaurant
and had a bad meal and decided to avoid the restaurant altogether, it
would be similar to predators avoiding all butterflies that have this
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