ECOLOGICAL MANAGEMENT

ECOLOGICAL MANAGEMENT
By the end of the lesson, students should be able to:
I. ASSOCIATION:
Recognise some of the different types of association existing between different species.
Identify beneficial harmful and neutral forms of association among organisms.
Deduce the mode of life of a given organism from observed characteristics.
II. TOLERANCE:
Discuss why living things possess a range of tolerance to environmental factors.
 List the abiotic factors that impose tolerance on organisms.
Depict tolerance range with a graph.
III. ADAPTATION:
State that adaptation may be a modification in response to environmental factors.
Describe the availability of water as the principal factor for plant and animal distribution.
List examples of adaptation to environmental factors.
IV. POLLUTION:
Define pollution.
Name air pollutants and their sources.
Enumerate the harmful effects of pollutant.
State effects of detergents, insecticides, artificial fertilizers and herbicides on aquatic and terrestrial organisms.
Identify poor sewage system as a source of pollution.
Name domestic and industrial wastes that pollute land and water.
Identify the decay of organic matter (e.g. dead animals and plants) as a source of pollution.

Biological Association.
This is the food relationship interactions between organisms in an ecosystem, which may be beneficial, neutral or harmful.
Any close and prolonged living together or association of two or more organisms of the same or different species which may be temporary or permanent, harmful, beneficial, or neutral to one or more or all the partners is termed symbiosis.
Types of Symbiosis:
Mutualism;
Parasitism;
Commensalism;
Competition.

Mutualism: A type of relationship in which two different kinds of organisms live together to the benefit of each other. Examples are:
Lichens: This is an association between alga and fungus. The alga provides food for the fungus through its photosynthetic activity, while the fungus provides water through rain water which is
used by alga to photosynthesis its food, it (fungus) also provides for the alga protection against physical damage and drying up.

Mycorrhiza: This is an association between a fungus and the root of a higher plant. The fungi act as root hairs and helps in the transfer of inorganic nutrients from the soil into the plant, while the plant provides the fungus with organic nutrients.
Insect pollinated flowers and insect pollinator: The flower supplies the nectar which the insect feeds upon, while the insect brings about effective reproduction in the plant by pollinating it.

Herbivorous animals and cellulose digesting bacteria in its intestine: These bacteria digest the cellulose of leaves and convert the digested cellulose to sugar which is absorbed by the herbivore, while the herbivore provides shelter and nutrients for the bacteria in the rumens and colon.

Nitrogen fixing bacteria in the root nodules of leguminous plants: The bacteria enter the root of a leguminous plant, causing cell division due to nodules formation, more so, the Rhizobium (the bacterium) fixes nitrogen directly into then plant, and hence, increasing the nitrogen requirement of leguminous plants. While the plant through its root provides nutrients for the growth of the bacteria.

Cattle and tick birds: Tick birds remove blood-sucking flies and ticks from the hides of cattle, in this case, the birds get their food by eating the ticks, while the cattle benefit by having their parasitic infestation reduced.


2. Parasitism: A type of relationship in which two different kinds of organisms live together to the benefit of one (i.e. the parasite) and the detriment of the other (i.e. host). Examples are:

Man and the ascaris/or tapeworm: The ascaris (i.e. roundworm) or tapeworm lives in the small intestine of man where it derives its nutrients, protection and habitat. The man who is the host suffers because he loses to the parasite part of the food he has eaten and digested. This is an example of endoparasitism because the parasite lives inside the body of the host.

Dog and the tick: The tick lives on the surface of the dog where it derives its food (i.e. nutrients) through sucking of the dog blood. The dog who is the host suffers anaemia because he loses to the parasite its blood. This is an example of ectoparasitism because the parasite lives on the outer surface of the host body.

Mistletoe/ or dodder (Cuscuta)/ or witch weed (Striga) and the flowering plant: The mistletoe/or dodder/ or witch weed are parasitic plants that live on flowering plants. The parasite derives support, and also absorbs water and mineral salts  from the flowering plant, while the host loses and harmed by losing to the parasite part of the water and mineral salts that it has absorbed.  This is also an example of ectoparasitism.

Effects of parasite on the host:
It damages the host's tissues.
It kills the host due to damages done to the tissue and due to toxic substances secreted.
Poor growth of the host.
 Discomfort.
 Weakness of the body or structure.
Lack of resistance to diseases.

Parasitic fungi: Some fungi are parasitic to green plants. Examples are:
Ustilago on maize.
Puccinia on maize, wheat or barley.
Phytophthora palmivora on cocoa.
Phytophthora infestans on tomato/potato causing blight
Alternation on tomato.

How parasites (endoparasites) enter the hosts:
Wounds.
Natural openings such as mouth, anus, nostril, ear, eyes in animals and stomata or lenticel in plants.

General adaptation of parasite: A parasite must:

be able to secrete enzymes to dissolve tissues of the host for easy penetration. This is common to endoparasites;
be able to cling or attach to the host's body surfaces (either internally or externally);
have organs that can penetrate through the host's body surface and absorb nutrients. This is common to ectoparasites;
have boring organs which will enable it to enter the body of the host. This is common to endoparasites.

Adaptation of gut parasites e.g. tapeworm, ascaris:

Presence of attachment organs onto the walls of the host gut. Such attachments are hooks and suckers in tapeworm;
ability to respire aerobically or anaerobically;
production of anti-enzymes to neutralize the host's enzymes;
possession of hard cuticles which cannot be digested by host's digestive enzymes;
presence of large surface area to small volume ratio for easy absorption of host's digested food.

How parasitic plants such as Mistletoe and Dodder are adapted to their parasitic life:
They grow on the stem of their host; they penetrate into the host using their sucker; absorb the nutrients from the host; using their sucker called haustoria.

How ectoparasite animals are adapted to their parasitic life:

They have an attachment structures such as claws, suckers and hooks, that enable them to cling to their hosts. Once they attach to the host's body surface, they pierce the host's outer tissues with their modified mouthparts; they suck blood of animals and secrete anti-coagulants to prevent blood clotting or the sap of plants if it is a plant parasite.
Examples of animal ectoparasite that feed on animals are leech, tick, bedbug.
Example of animal ectoparasite that feeds on plants sap is aphids.

Other example of plant parasite is Cassytha.


Assignment:
1. Discuss the life cycle of tapeworms.
2. Differentiate between the following; Tania solium and Tania saginata. Draw and label fully their diagrams.
3. Differentiate in a tabular form, parasitism and saprophytism.

3.    Commensalism: A type of relationship between two organisms of different species in which one of the organisms benefited (i.e. commensal) while the other is neither benefited nor harmed (i.e. host). Examples are:

Remora fish (shark-sucker) and shark: The remora attaches itself to the underside of the shark. The remora feeds on the scraps/left over of shark food. It (remora) also gets protection, and shelter from the shark, whereas the shark is neither harmed nor benefited as a result of the presence of the remora fish.

Oyster and crab: The crab gets shelter/habitation in the oyster shell, whereas the oyster is not harmed.

Epiphyte and a tree: The epiphyte gets a site where it can get enough sunlight to cary out photosyntheses, whereas the tree is not affected.

Dispersal of the fruits of some plants by animals: The fruit of Triumfetta is dispersed by passing animals such as sheep. Triumfetta plant benefits by having its fruits dispersed to a new environment while the animal is not harmed.

Kite and trees: A kite builds its nest on the branches of big trees like Iroko. The tree provides the Kite shelter, whereas the tree does not gain anything from the Kite nor harmed.

Sea cucumber and Fierasfer: The fish called Fierasfer lives in the rectum of sea cucumber. The fish comes out frequently to feed and returns to the rectum by poking the anus of the sea cucumber and enters with its tail. The fish gains shelter and the sea cucumber does not gain nor harmed.

Assignment
Deduce that there is no mutualism neither commensalism that will not lead to parasitism.

4. Competition: This is a type of association between a number of organisms of the same or different species for resources in limited supply such as food, water, space, light, suitable temperature, and mates.

Types of Competition.
There are two types of competition namely:
Intraspecific competition; and
Interspecific competition.

Intraspecific competition: This type of competition involves organisms of the same species. Examples include: planting of flowers or any other plants or crops too close together in a flower bed or space or heap, the plants will compete for space, light, water,  gases, and soil nutrients.

Effect of intraspecific competition: stunted growth and poor flowering and death if not checked. In a nutshell, overcrowding results in intraspecific competition.


How plants and animals have been able to solve problem of intraspecific competition:

To avoid intraspecific competition, overcrowding is solved, hence, plants disperse their spores, seed and fruits by various dispersal mechanism, while animals emigrate, while in human, birth control methods are adopted.

Interspecific competition: This type of competition involves two or more organisms of different species using the same limited resources.
 Effects of interspecific competition:

The stronger competitor may drive the weaker ones into extinction;
One species may enjoy competitive superiority in some regions while the other may be competitively superior in other regions with different environmental conditions.

Examples of interspecific competition include: 1. Two species of duck weeds, Lemma gibba, and Lemma polyrrhiza which grow equally when alone, but L. gibba always replaces L. polyrrhiza when they are grown together. 2. Two species of Paramecium, namely P. caudatum and P. aurelia. 3. Flowering plants and grasses.

The term allelopathy: This is an interaction in which one organism releases a chemical substance(s) into an environment causing a harmful effect on other organisms. For example, the release of chemical substances from the male inflorescence of maize flower inhibits the growth of other grasses near that area while the seed germination of maize is not affected. The maize plant has shown superiority over other plants, hence it will eliminate other plants.

Tolerance.
Tolerance is the ability of a living thing to successfully cope (withstand) with the extreme variations (upper and lower) limits of an environment which affect their survival.
Tolerance Range
This is the range between upper/maximum and lower/minimum limits of abiotic factors affecting the survival of living organisms in a particular area or habitat. Any abiotic factors affecting the organisms below or beyond this limits result in death of the organisms. For example, in most animals, the minimum temperature (i.e. abiotic) limit is 0°C and the maximum limit is 42°C . Their tolerance range is 0°C to 42°C. Anything below 0°C (the lower lethal temperature) and above 42°C (the upper lethal temperature) results to death!

Physiological Stress
 This is a phenomenon which occurs as a result of subjecting an organism beyond its optimum range (the range within which the species' growth and reproduction are at their peaks) which results in a steady fall in its growth and reproductive rate.

Geographic Range
This is the presence of a particular species only in a particular area or geographical region which is within their minimum and maximum limits of their tolerance range.  For example some organisms are limited only to arctic temperate or tropical regions due to temperature factor.

Abiotic factors that impose tolerance on organisms.
Temperature
pH
Soil type
Water//rainfall
Topography/altitude
Pressure
Sunlight/light
Air
Wind
Relative humidity/atmospheric humidity.
Graph showing tolerance range, optimum range and population size.

Adaptation
Adaptation is the ability of an organism to survive and reproduce successfully in any given environment or habitat over a long period of time due to possession of structural, functional or behavioral features.
Plants and animals possess certain features which enable them to adapt to either aquatic or terrestrial habitats.

Adaptation of plants to aquatic environment
Plants that live successfully in water are called hydrophytes. They include Eichornia (water hyacinth), water lily (Nymphaea lotus), Nuphar, red mangrove (Rhizophora racemosa), white mangrove (Avicenna spp.), Raphia palm, Pistia stratiotes(water lettuce), Elodea, Potamogeton, Duckweed ((Lemna) etc.
Adaptation include:
Possession of waxy cuticles on leaves to prevent wetting, e.g. water lettuce.
Possession of long stem and flower stalk to expose the flowers and leaves, e.g. water lily
Possession of air floats in the leaves and stems for buoyancy e.g. water hyacinth
Possession of breathing roots for gaseous exchange e.g. white mangrove
Possession of air spaces in the tissues for buoyancy e.g. water lettuce
Presence of chloroplasts on the leaves and stems                   for photosynthesis/manufacturing of food
Variable leaf shapes to prevent a minimum resistance to water currents and increase the surface area for water and mineral absorption e.g. Potamogeton
Flowers are raised above water for the purpose of pollination

Adaptation of plants to terrestrial environment
Plants living on land can be grouped into two, based on their need for water. These groups include:
Mesophytes: These are plants that live in a moderate condition of water supply (i.e. neither too dry nor too wet), e.g. cashew tree, oil palm tree, maize, yam, cassava, cocoyam, sweet potato
Xerophytes: These are plants that need very small amount of water to live e.g. Desert plants such as Cactus, Euphorbia, Acacia, Aloe, Portulaca.

Adaptation of mesophytes to their environment
Possession of large and flattened leaves to increase gaseous exchange
Possession of waxy cuticle to minimize water loss
Presence of stomata on the leaves for gaseous exchange
Presence of chloroplasts for photosynthesis
Possession of numerous leaves to enhance better photosynthesis
Adaptation of xerophytes to their environment
Presence of succulent stems for water storage e.g. Cacti, Euphorbia, and Opuntia
Presence of succulent leaves to conserve water e.g. Bryophyllum
Possession of deep tap root with extensive lateral roots to source for water e.g. Acacia, Baobab
Leaves are reduced to spine (e.g. in Cactus), or thorns (e.g. in Acacia), or reduced to scale-like structure (e.g. in Casuarina i.e whistling pine) to reduce rate of water loss/transpiration
Possession of thick bark to prevent destruction of parts due to fire outbreak e.g. Baobab
Presence of sunken stomata or lower number of stomata to reduce water loss


Adaptation of animals to terrestrial environment
Possession of hairs, in mammals, feathers in birds and scales in reptiles to regulate body temperature
Presence of lungs for respiration
Presence of sweat glands for excretion and thermoregulation
Presence of skin (e.g. Mammals) and exoskeleton (cuticle) in insects for protection against injury and desiccation
Possession of pairs of limbs to escape predator
Adaptation of animals to aquatic environment
Presence of lateral line to detect vibrations in water, hence adaptation to escape predator
Presence of fins (e.g. Fish) and webbed digits (e.g. Toad) to facilitate swimming
Presence of gills (e.g. Fish) and siphon-like tubes (Mosquito larva) for breathing
Possession of streamlined body to offer minimum resistance to water flowing over them
Presence of suckers or hairs for attachment to vegetation to avoid being swept away by water current e.g. Leech
Possession of nicitating membrane over eye in fishes and presence of eyelids in toads and frogs
Ability to burrow and remain in moist habitats to escape predators e.g. Annelids, clams, and snails

Adaptation of some organisms

Adaptation of toad or frog for food, protection and movement

(A) for food
It possesses special olfactory organ in the head for smelling/perceiving the odometer of its food
It has the ability to draw eyes in so that they make bulges in the root of the mouth which help to prevent their prey from escaping and help in swallowing
The tongue is attached at the front of the mouth which can be rapidly extended to capture/trap prey
The tongue is long and sticky to help hold the prey.

(B) for protection
The skin is slimy with mucous gland which makes the animal difficult to be caught by predators
Slimy fluid keeps the skin moist and prevents the skin from drying up
Toad  has poison glands on the skin which is poisonous and distasteful to the predators
Cryptic coloration to prevent them from being noticed by enemies and predators
The colour can be altered to match the type of background.

(C) for movement
Presence of powerful muscular hind limb to hop/jump, hence escape predators
Absence of tail facilitates hopping or jumping movement
Webbed hind limb can be used as paddle for efficient swimming in water
The stout and short nature of fore limb absorbs shock on landing and for propping up the front end of the body on landing after a jump or hop
Presence of streamlined body for easy movement and swimming
Adaptation of chameleon/lizard
Possession of long, sticky tongue for capturing preys
Possession of claws on the feet for holding objects on which it walks
Possession of powerful eyes to see preys and predators easily
Possession of scales to prevent desiccation
In chameleon, there is ability to change the colour of the body in order to hide from its predators.

Assignment
Discuss the adaptation of the following organisms to their environment:
Endoparasite e.g. Tapeworm
Tilapia fish
Tadpole