8.1 Biotic & Abiotic Components

Dynamic Ecosystem

ECOSYSTEM:Collection of living

things and the environment which

they live

ENVIRONMENT:Consist of living

organisms (biotic factor) & non-living organisms

(abiotic factor) ECOLOGY: Scientific study on the

relationships of organisms with their physical

environment and with one another

Natural Ecosystem

Natural Ecosystem

Artificial ecosystem

Ecosystem

Biotic Components

Abiotic Components

ABIOTIC COMPONENTS

ABIOTIC FACTOR

pH value temperature

Light intensity

Topography Microclimate

Humidity

pH value

• Acidic , neutral or alkaline• Influences the growth & distribution of aquatic & land

organisms

SLIGHTLY ACIDIC SLIGHTLY ALKALINE

Maize Soya Bean

TomatoBarleyPotato

FernsCoconut

Casuarinas

Temperature

Temperature influences the :

the productivity of producers

distribution of soil organisms

a. Productivity of producers

• In polar regions & desert• productivity is low• Living things in these places have adaptations to survive• E.g. • Poikilothermic –found in warm climate• Homoeothermic - widespread• Thick fur in cold climate• Absence of leaves in the cactus that live in desert

b. Distribution of soil organisms

• Low soil temp : reduce the rate of water & mineral soil absorption• Organisms living in ground : population do not change

much because temp uniform• Above the soil: daily & seasonal temp change influence

distributions & populations & living organism• Temp of sea : more stable because aquatic animals do not

adapt well to big temperature change

Light intensity

• Influence the rate of photosynthesis• Distribution of green plants denser in areas

of high light intensity• Aquatic plants : found near the surface of

water

Humidity

• Influences the rate of water loss in plants & animals• Many plants & animals thrive in humid ecosystem of

sheltered caves or jungles

Topography

• The description of the surface features of a place• Altitude, gradients of a slope & other physical aspects :

determine of sunlight reach earth surface

Microclimate

• Refers to the climate of a small place / habitat• Involves differences in terms of quantity of rain, relative

humidity, light intensity, change in temperature• Influences the number and distribution of living

organisms

BIOTIC COMPONENTS OF AN ECOSYSTEM

Biotic components

Plants

ManAnimals

Biotic components of an ecosystem

• Biotic components interact with each other directly / indirectly

• Types of relationship between biotic components:a) Competition

b) Symbiosis

c) Saprophytism

d) Prey-predator interaction

Classifying biotic components into trophic levels

• Ecosystem has three main nutritional groups:

1) Producers

2) Consumer

3) Decomposer

Producer

• Green plants ; photosynthesis

• Produce enough food for their own consumption & consumer

Consumer

• Primary• Secondary • Tertiary

Decomposer

• Consist of bacteria & fungi

• Break down waste products & dead bodies of other organisms into simpler substances

• Can be use again

Food Chain & Food Web

Trophic levels

Revision

An ecosystem is a community of organisms / biotic components which interact with their non living environment / abiotic components

Squirrel eat fruits from the tree // Big bird eat mouse in the garden

10% X 1500 kJ= 150 kJ

. Lost to atmosphere as heat energy

. Used to decompose dead matter (by decomposer)

. Used to carry out metabolism reaction in cells

. Respiration

. Excretion

. Defecation

F : Deforestation / logging / open burningE1 : Extinction / destroy of flora / faunaE2 : loss of biodiversityE3 : disruption of food chain / webE4 : Land slides / soil erosion / water pollution / flash flood

Interaction between Biotic Components in Relation to Feeding

• Four types of biotic interactions:

a. Symbiosis

b. Saprophytism

c. Prey-predator

d. competition

Symbiosis

• Means ‘living together’

• Close & permanent relationship

• Between 2 or more different species

Symbiosis

Commensalism parasitism mutualism

commensalism

• Benefits one species (commensal) but neither benefits nor harms the other species (host)

Commensalism

Epiphytes Epizoics

Epiphytes

• Green plants that grow on branches or tree

• Do not derive their nutrition from the tree

Epiphytes ferns

• Adaptations:• Thick waxy cuticle to

prevents water loss• “nest” collects fallen

leaves, pieces of tree bark etc

• Ants nests – increase organic matter

Staghorn fern (Platycerium coronarium)

Bird’s nest fern(asplenium nidus)

Epizoics• An animal commensal

attched to other animals (its host)

• For free transport, feed on leftovers from their host meal

• Host neither suffer loss nor benefits

cyclops

vorticella

daphnia

Shark & remora fish

Parasitism

• Relationship between two organism • The parasite benefits; Host is harmed• Two types:• Endoparasites• Ectoparasites

Endoparasites

• Adaptations:• Reduction in nervous

system & sense organs• Reduced digestive tracts• Have protective cuticles

& produce mucus and anti-enzymes

• Have flattened shape• Anaerobic respiration• Produce a lot of gametes

tapeworm

fluke

Round worm

Ectoparasites

• Adaptations:• Have hooks to attach

themselves• Have sharp mouth

parts for hooking, sucking or biting

aphid

Tree bugs

lice

Plant parasite

Dendrophthoe sp (dedalu)

Mutualism

• Relationship between two species of living organisms • Both benefits• E.g.• Lichens• Sea anemone & hermit crab• Rhizobium in the nodules of leguminous plant• Microorganisms & herbivores

Lichens

• Green alga + fungus• Grow on tree bark• Green alga gets• shelter, water, minerals

& nitrogenous compounds

• Fungus gets• food & oxygen

Sea anemone & hermit crab

• Hermit crabs gets protection from tentacles of sea anemone

• Sea anemone gets transport & left over food

Rhizobium in the nodules of leguminous plants

• The bacteria convert atmospheric nitrogen into ammonium compound that are used by the plants

• Bacteria get shelter & energy rich compounds from the plants

Microorganism (protozoa & bacteria) and herbivores

• Bacteria lives in the alimentary canal• Produce cellulase• Large part of the sugar produced absorbed by host• Microbes gets shelter & food

Saprophytism

Saprophytes Saprozoites

Saprophytes

• Plant that gets its food from dead organism

• Cannot make own food• Produces enzymes to

digest & decompose dead complex organic matter

• E.g.:• Bread mould• Mushrooms• Bracket fungus

Saprozoites

• Animals that feed on dead organic matter that has been digested

• E.g.:• Protozoa found in the

intestine of the frog (Opalina sp. & Balantidium sp.)

• In rectum (Nyctotherus sp.)

Opalina sp

Balantidium sp

Nyctotherus sp

Prey predator relationship

Prey-predator relationship

• Exists when a weaker animal (prey) is hunted & eaten by another stronger animals (predator)

• Predator : moves fast, long canine teeth/ sharp claws• Prey : use speed & camouflage• Important to keep different animal populations of an

ecosystem in balance

PREDATOR

PREY

Prey-predator relationship

• Predator : moves fast, long canine teeth/ sharp claws• Prey : use speed & camouflage

Prey-predator relationship

• important to keep different animals population in an ecosystem in balance

• Self regulating and keep the populations of both the predator and prey in a DYNAMIC EQUILIBRIUM

Interactions between the Biotic Components in relation to Competition

Competition

• An interaction between organisms living together in a habitat and competing for limited resources

• Animals :• Food, shelter & breeding mates

• Plants:• Light, nutrients & water

• Two types of competition:a) Interspecific competition

b) Intraspecific competition

Interspecific Competition

• Competition between individuals of two or more different species

P. caudatum

P. aurelia

Interspecific Competition

Intraspecific competition

• Competition between individuals of the same species

EXERCISE