5. Interspecific Relationships

Orientation in Space

Orientation in Time

Species Interactions

Intraspecific Relationships

Overview of Interspecific Relationships

No organism exists in isolation. Each interacts with other organisms of its own and other species. Interspecies interactions (those between different species) involve benefit to at least one party.

If one party benefits at the expense of another, the relationship is an EXPLOITATION.
If one species benefits and one is unaffected, the relationship is said to be COMMENSALISM.
Some species interactions involve a close association or SYMBIOSIS (living together) between the parties involved. Symbioses include PARASITISM and MUTUALISM.

Many species interactions involve coevolution, in which there is a reciprocal evolution of adaptations in both parties.

Concept 15: Symbiotic Relationships

Success Criteria & Vocabulary

Click this drop-down menu to see the Success Criteria.

I can define the term “interspecific symbiotic relationships”.
I can describe and give examples of symbiotic relationships including parasitism, mutualism, and commensalism in terms of -ve, +ve, and mutual interactions.
I can describe the adaptive advantage of symbiotic interactions.

Click this drop-down menu to see the list of Vocabulary.

Batesian mimicry: A form of mimicry where a harmless species resembles a dangerous, unpalatable species.

Commensalism: An interspecific relationship where one species benefits while the other is unaffected.

Exploitation: Any interaction between individuals of different species in which one individual benefits and the other is harmed, e.g. parasitism, predation, herbivory.

Faculative mutualism: Type of mutualism where both species benefit from interacting with each other but can survive without the interaction

Herbivory: A form of exploitation, involving an animal feeding on a plant.

Mimicry: Where one species resembles another in some way.

Mullerian mimicry: A form of mimicry where two unpalatable species resembles one another.

Mutualism: A mutually beneficial interaction between individuals of different species.

Obligate mutualism: Type of mutualism where neither species can survive without the other.

Parasitism: A type of symbiosis between organisms of different species where one organism benefits at the expense of the host.

Predation: The relationship where an individual of one species kills and eats the individual of another species.

Symbiosis: Interspecific relationship between two organisms live together in close association, in either mutualism, commensalism, or parasitic relationships.

Tasks

Complete Education Perfect:

Task called '3.3 Concept 15'.

Photoperiodism in Plants
Phytochrome
Vernalisation, Seed Dormancy, and Abscission

Complete sciPad:

Mark your own work using the sciPad online answers.

Learn the 12 keywords using Quizlet:

Concept 15: Support Notes

Summary of Symbiotic Relationships

Mutualism Involving Animals

MUTUALISM is a SYMBIOTIC relationship between two different species in which both interacting species benefit from the association.

There are three types of mutualistic relationships:

Resource-resource relationships
Service-resource relationships
Service-service relationships

Resource-resource relationships: One resource is traded for another (usually food or a nutrient).

For example: Many reef building corals rely on mutualism with algae in their tissues. The corals obtain some of their energy from the algae. The algae obtain a habitat and utilise the coral's nitrogenous waste and carbon dioxide.

For example: Termites, which feed on wood, rely on a community of microbes in their gut to break down the cellulose in wood and produce the fatty acids the termites use for energy. The obligatory relationship provides food for both microbes and termites.

Service-resource relationships: A service is performed in exchange for a resource, e.g. food or protection.

For example: Some species of ants "farm" aphids by protecting the aphids from predation by ladybirds. In return, the ants harvest the honeydew produced by the aphids.

For example: Many large grazing animals rely on oxpeckers to remove parasite infestations. The grazers provide food to the birds and the birds provide an anti-parasite service.

Service-service relationships: Both organisms provide a service to each other. True service-service mutualisms are very rare and there is usually some resource component present.

For example: Clownfish protect their home sea anemone by chasing away predators, e.g. butterfly fish. In return, the sea anemone protects the clownfish from its predators. However, the anemone's symbiotic algae also benefit from the nitrogen excreted by the clownfish.

For example: Acacia ants nest within the thorns of the bullhorn acacia. In exchange for shelter, the ants protect acacias from attack by herbivores. There is a resource component though because the ants feed on the lipid rich bodies at the tips of the acacia leaflets.

Mutualistic relationships can be obligate or facultative

Some mutualistic relationships are OBLIGATE, meaning that one (or both) species cannot survive the its mutualistic partner.

Other mutualistic relationships may not have the same level of dependency, and the relationship is not necessary for the survival of either species. These associations are termed FACULATIVE mutualism.

In a facultative mutualism, both species benefit from interacting with each other but can survive without the interaction. In many cases, a species ay interact mutualistically with many similar species.

For example: Bees pollinate many different types of flower. The flower can use any type of bee as a pollinator and the bee can visit any type of flower to gather nectar.

In an obligate mutualism, neither species can survive without the other. There is a mutualistic relationship between many herbivores and the microbes in their gut, which enable cellulose to be digested.

For example: In cows, the microflora (good bacteria) in their stomachs break down the cellulose in forage (food obtained from grazing or browsing). The cow obtains energy from the fatty acids released by the bacteria. The bacteria benefit by having a stable growth environment and a food supply.

Exploitation - Parasitism

EXPLOITATION is the relationship between two different species where one species benefits while the other is harmed - one species benefits at the expense of the other. There are three types of exploitation:

Parasitism (IS symbiosis)
Predation (NOT symbiosis)
Herbivory (NOT symbiosis)

Parasitism is a Symbiotic Relationship

PARASITISM involves one organism, called the parasite, living on or inside another species, which is called the host.

Unlike predators, parasites don't want to kill their host. Instead, they benefit by having a secure home for reproduction or by taking some of the host's resources, like food, water, and heat. The host is harmed because it simply has less resources.

Commensalism

COMMENSALISM is slightly different in that it is the relationship between two different species where one benefits while the other is unaffected.

The benefit usually comes from the supply of food, shelter, or transport, and usually involves a large host and a small commensal (the one benefiting).

Example: A spider has established a web around this gazelle's horns.

Example: Camouflage is an organism's ability to blend in with its surroundings. This tree frog is camouflaged as it blends in with the surrounding tree bark. It does this to hide from predators or catch prey.

Concept 16: Exploitation & Avoidance Strategies

Success Criteria & Vocabulary

Click this drop-down menu to see the Success Criteria.

I can describe and give examples of exploitation, herbivory, and predation in terms of -ve and +ve interactions.
I can describe various predator avoidance strategies/adaptations including camouflage, mimicry and aposematism.
I can discuss the adaptive advantages of exploitation, camouflage, aposematism, and mimicry.

Click this drop-down menu to see the list of Vocabulary.

Aposematism: Display of warning colouration to warn predators that it is poisonous or unpalatable.

Batesian mimicry: A form of mimicry where a harmless species resembles a dangerous, unpalatable species.

Camouflage: Blending into the background to deceive or evade a predator (or prey).

Exploitation: Any interaction between individuals of different species in which one individual benefits and the other is harmed, e.g. parasitism, predation, herbivory.

Herbivory: A form of exploitation, involving an animal feeding on a plant.

Mimicry: Where one species resembles another in some way.

Mullerian mimicry: A form of mimicry where two unpalatable species resembles one another.

Parasitism: A type of symbiosis between organisms of different species where one organism benefits at the expense of the host.

Predation: The relationship where an individual of one species kills and eats the individual of another species.

Tasks

Complete Education Perfect:

Task called '3.3 Concept 15'.

Photoperiodism in Plants
Phytochrome
Vernalisation, Seed Dormancy, and Abscission

Complete sciPad:

Mark your own work using the sciPad online answers.

Learn the 9 keywords using Quizlet:

Concept 16: Support Notes

What is Exploitation?

Parasitism (IS symbiosis)
Predation (NOT symbiosis)
Herbivory (NOT symbiosis)

Herbivory

HERBIVORY is a type of predation, which involves one animal species feeding on a plant species. The plant is harmed because the population or the plant decreases in size.

Plants must have strategies to defend themselves against herbivory:

Thorns
Divarication - meaning plants have branches of wide angles and intertangled to reduce the amount of browsing on the plant.
Chemicals - makes seeds/leaves unpalatable.
Seed masting - abundance of seed production followed by no seed production. This strategy has the potential to regulate the population of seed predators.
Nastic response - leaves drop to expose thorns.

Predation

PREDATION is where one animal hunts and feeds on another. The one that gets to eat benefits, while the one that dies and gets eaten is harmed.

Over many generations, predators and prey act as agents of natural selection, leading to evolution of adaptations that promote survival.

Camouflage (Predator Avoidance Strategy)

Prey can deceive and evade a predator through camouflage.

Aposematism (Predator Avoidance Strategy)

For an animal that defends itself using chemicals and poisons, it is advantageous to warn potential predators of the danger.

Therefore, many poisonous animals display brilliant aposematic or warning colouration, making them very visible and obvious.

This is called aposematism.

Mimicry (Predator Avoidance Strategy)

One sneaky way of avoiding predators is MIMICRY, where one species resembles another in some way. It could be mimicking appearance, behaviour, sounds, or even smells. There are two types of mimicry you should know about:

Batesian mimicry

BATESIAN MIMICRY is where a harmless species mimics a dangerous or poisonous one. Predators will see the mimic and think "oh no, those are poisonous animals that make me sick" and avoid eating the mimic.

Therefore, Batesian mimcry protects the species against predators.

Mullerian mimicry

The other main type of mimicry is MULLERIAN MIMICRY. Mullerian mimicry is where to unpalatable species (animals that aren't tasty) mimic each other's warning signals.

If you have two unpalatable species that don't resemble one another, a predatory will try to eat one species, find out they taste gross, and then move on to taste the second species.

What would be more beneficial to both species is that they look like each other, so that when the predator learns not to eat one species, it effectively learns not to eat both since they look the same to the predator.

For example: The Heliconius butterflies from the tropics of the Western Hemisphere are classic Müllerian mimics

You should watch this great video on Aposematism and Mimicry.

Concept 17: Allelopathy & Interspecific Competition

Success Criteria & Vocabulary

Click this drop-down menu to see the Success Criteria.

I can explain what causes interspecific competition.
I can describe Gause’s competitive exclusion principle.
I can explain how occupying a specific niche reduces interspecific competition and can lead to zonation, stratification, and succession.
I can describe allelopathy as a form of antibiosis.

Click this drop-down menu to see the list of Vocabulary.

Allelopathy: Plant defence by producing chemicals that inhibit the growth of other plants near them.

Altitudinal zonation: Type of zonation occuring in mountainous regions.

Antibiosis: Microorganism defence by producing chemicals that inhibit the growth of other microorganisms. Marine animals can also do this.

Gause's principle: No two species can occupy the same ecological niche and stably coexist - one will ultimately outcompete the other.

Intertidal zonation: Type of zonation occuring in coastal regions.

Primary succession: Type of succession that occurs over a long period of time when the environment is initially unfavourable.

Secondary succession: Type of succession that occurs over a short period of time when the environment is fertile.

Stratification: Vertical pattern in species distribution in a community.

Succession: Pattern of species distribution in a community over time.

Zonation: Horizontal pattern in species distribution in a community.

Complete Education Perfect:

Task called '3.3 Concept 15'.

Photoperiodism in Plants
Phytochrome
Vernalisation, Seed Dormancy, and Abscission

Complete sciPad:

Mark your own work using the sciPad online answers.

Learn the 10 keywords using Quizlet:

Concept 17: Support Notes

Competition & Gause's Principle

In all environments, resources (like food, shelter, mates) are finite, so there are limits to how many organisms a given environment can support. Interspecific competition is where two or more different species compete for resources.

According to GAUSE'S PRINCIPLE, no two species can occupy the same ecological niche and stably coexist. If two species occupy the same niche, one will eventually outcompete the other, or force it out of the habitat.

The more similar their niche is, the more intense the competition.

For example: A Northern rātā tree and Rimu tree living in the same habitat cannot coexist stably because they are fiercly competing for light, space, and water and nutrients from the soil.

Eventually the much younger and robust Northern rātā outcompetes the much older Rimu tree.

Interspecific competition can be reduced by the following ecological patterns that distribute species in a community:

STRATIFICATION
SUCCESSION
ZONATION

Stratification

STRATIFICATION is a distinct vertical pattern in the species distribution in a community. Last year, you learned about stratification in a forest community. But stratification can be seen in other plant communities, as well as animal communities.

For example, a community of birds living in a single tree can exhibit stratification, especially during the breeding season and if the different species are closely related

Another example of stratification is seen in lakes where different fish species distribute themselves into vertical layers as a result of oxygen and food requirements.

(RIGHT: Stratification of fish due to a gradient in lake water temperatures and oxygen availability).

Zonation

ZONATION is a distinct horizontal pattern seen in the species distribution across a community. The species best adapted to the particular environmental conditions present in a zone tends to be the dominant species. Once the environmental conditions exceed the limits of tolerance for that species, another species forms the next zone.

There are two types of zonation:

ALTITUDINAL ZONATION occurs in mountainous regions
INTERTIDAL ZONATION occurs in coastal regions.

Succession

Succession is a distinct pattern over time, seen in the species distribution of a community. When a new habitat becomes available, it takes a long time before the community re-establishes itself.

Whole sequences of communities replace one another as species within each community change the physical environment, making it more favourable for the successor species.

There are two types of succession:

Primary succession
Secondary succession

PRIMARY SUCCESSION occurs in coastal habitats.

The environment is initially so unfavourable to plant growth that only a few pioneer species can survive.

SECONDARY SUCCESSION occurs when fertile soil exists from the beginning, and is consequently much more rapid than primary succession.

An example is the re-growth of forest after fire or felling (cutting down trees).

Allelopathy and Antibiosis

Some plants reduce competition from other species by producing chemicals that inhibit the growth of other plants.

In walnut trees, chemicals are produced by the roots, and also by the leaves, and become effective when they fall to the ground. This is ALLELOPATHY - producing chemicals that inhibit growth.

A similar phenomenon occurs in many microorganisms (fungi and bacteria), which produce antibiotics - substances that inhibit the growth of other microorganisms.

ANTIBIOSIS also occurs in many marine animals, such as sponges.

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