Abiotic & Biotic Factors

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Abiotic Factors

Temp

Light

Water

Atmospheric Gases

Wind

Soil

Physiographic

Temperature

Indication of the amount of heat energy in the system

Plants cannot regulate own temp, animals can.

Most animals keep body temp by gaining heat from external source

Poikilothermic - Having body temp that varies according to the temperature of its surrounding

Endothermic - Maintain constant body temp - metabolic heat production

Temp influence rate of numerous physiological processes -- transpiration, respiration, reproduction.

Soil temp - rate of absorption by roots & rate of root growth.

Alpine zone, mountains - Trunks covered by a dense layer of dead dry leaves to insulate their inner tissues.

Perennating Tissues

Meristematic tissue, inactive during unfavorable condition, resumes growth during favorable conditions. Helps plant survive during unfavourable seasons.

Meristematic - cells that have the ability to divide. (buds, seeds, rhizomes, tubers)

Animals adapt

Small mammals - fat & hide in burrows / hibernate. Some huddle together (penguins & honey bees)

Large mammals - Increase fur thickness & subcutaneous fat.

Hot temp - some sweat ( Sweat evaporates, cooling body.)

Ungulate, dog, birds -- panting, cooling of blood to brain

Light

- Primary source of energy (sunlight)

- Sunlight, energy for plants for photosynthesis. Light is absorbed by chlorophyll. Plants create/manufacture organic subs by combining inorganic subs.

- Visible light - most important

Quality of light

Plants = blue & red light during photosynthesis

Aquatic = quality of light = limiting factor

Blue & red absorbed but doesn't penetrate water well

Compensation - algae, extra pigment, able to absorb other colours.

Light Intensity

Southern hemisphere <12hrs of light during winter(march-sept) but >12hrs during summer oct-feb)

Northern hemisphere <12hrs during winter (nov-feb) & more 12hrs> during summer (march - oct)

Day length

Certain plants flowers only during certain times a year.

Plants reacted to day length

Photoperiodism - Relative lengths of daylight or darkness that affect the physiology & behaviour of an organism.

Short day plants - Flower only if nights are longer than a certain critical length.

- Chrysanthemum ( Chrysanthemum sp.) & poinsettia ( Euphorbia pulcherrima) & thornapple (Datura stramonium ; datura).

Long day plants - flower if nights are shorter than a certain critical length.

- Spinach, wheat, barley, clover, radish.

Day-neutral plants

- Not influenced by night length/ Tomato (lycopersicon esculeutum) & maize plant (zea mays)

Migration of bird

- Birds estimate changing of seasons based of light level from sun angle in the sky & amount of daily light.

Epiphytes - Plants, no roots in the soil & supported by other trees. Epi - beside/attached to. Grow on branches of other trees. Only for support, attains moisture from air & trapping constant leaf fall & wind-blown dust.

Bromeliads *pineapple fam) - lots in neotropics : orchids.

Lianas : woody vines, grow up the tree trunk when there is a temporary gap in the canopy & flower & fruit in the tree tops.

Climbers - Remain in the understory. Many climbers store nutrients in roots & tubers. (yams & sweet potatoes in africa & south america)

Stranglers - begin as epiphytes in canopy & roots are sent to the FF.

Some plant aren't autotrophic.

- They get nutrition from other resources.

Heterotrophs = Get it's nutritional requirements from complex organic substances.

= Parasitic plants - Tapping into the roots or stems of photosynthetic species.

- Rafflesia arnoldi = root parasite = linana. Odor of rotting flesh to attract pollinating insects.

= Saprophytic - Derive nutrients from decaying organic matter (orchids, fungi & bacteria)

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WATER

Most important abiotic factors

Moisture [Ocean --> clouds --> rain --> ocean)

Plants = 3 groups following their own requirements for water.

Hydrophytes = Plants that grow in water (rushes, water-lilies)

Mesophytes = Average water requirement (roses, sweetpeas)

Xerophytes = Grow in dry env, always experience a shortage of water (canctus, succulents)

Plants surviving without water adaptations

Reversed stomatal rhythms

Sunken stomata

thick cuticles

small leaves/absence

Water-storage tissues

Animals surviving without water

Covering of body helps limiting water loss = Chitinous(chitin) for insects & arachnids, scales(reptiles), feathers(birds) & hair(mammals)

Few/none sweat glands, Independent of evaporative cooling

Tissues = tolerant to water loss (camel, body tissues can adapt to water loss.

Ability to absorb water in the form of water vapour. (Dew from coastal fog, source of moisture for insects.)

Atmospheric Gases

Oxygen = Respiration

CO2 = Green plants, for photosynthesis

Nitrogen = Available to plants by certain bacteria & lightning

Wind

Caused by a complex interaction between hot air expanding & rising (convection) in the mid latitude

Effects the rotation of the earth

Causes centrifugal force (Coriolis force) - lift the air at the equator

Carry water vapour that can fall in the form of rain or slow or hail

Pollination & seed dispersal & dispersal for animals like insects

Wind erosion, move & redistribute topsoil especially at places where vegetation has been reduced.

Windy area = smaller plants

Soil (Edaphic Factors)

S texture

S air

S temp

S water

S solution

S pH

S organisms & decaying matter

S texture

Size varies, microscopic = clay, larger particles = sand.

Sandy soil - suitable - well aerated - drains away excess water quickly - warm up quick during the day - can be cultivated easily. Unsuitable - doesn't retain much water - dry out - has few soil nutrients for plant growth.

Clay - suitable - hold large quantity of water - rich in nutrients. Unsuitable - badly aerated - waterlogged - difficult to cultivate - cold during winter.

Loam soils - has both properties of sand and clay - retain water at high capacity - good aeration - high nutrient content - easy to cultivate.

Soil pH

Acid or alkali influence biological activity. Great influence on growth & development of plants.

- Some grow best in acidic soil (below pH 7) - azaleas, ericas, ferns

- Lucern & xerophytes better in alkaline soils (pH above 7)

Physiographic Factors

Physical nature of the are (altitude, slope of land, position of the area to the sun or rain-bearing winds )

Altitude plays a role in vegetations zones.

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BIOTIC FACTORS

- All living organisms & the waste produced

- Large, small & microscopic life forms.

- Most diverse & can change easily due to pollution, abiotic changes, disease & balance of food chain.

Definition

- All organisms in ecological setting

- All that are considered alife

- Animals, plants, trees & waste like falling trees

- Some have high BF and low AF, like forested areas. In desert, AF are predominant, few BF, which is more valuable because it is scarce.

Implications

- Biotic changes occur more easily & threaten an ecosystem more completely. - Disease, or predator, can change 1 link in the food change, it will affect all life forms.

Interactions

Biological community of an area is a complex network of interactions

Intraspecific = among diff indv. of the same sp.

Interspecific = among indv. of diff sp. in a community.

Amensalism

Negative association between 2 species, 1 harms/restricts the other even tho it isn't being harmed by the presence of the other species.

Predation

Predator captures, kill, and eat the prey. (animal of other species)

Predator benefits, prey harmed.

Parasitism

One harmed, one benefits.

Small size organism living in/on other species - host. Parasite obtain nourishments & shelter.

Parasite benefits, host harmed.

Vertebrate hosts & animals like tapeworms, flukes, plasmodium species & fleas.

Commensalism

2 org, 1 benefits & other not affected.

Trees & epiphytic plants, epiphytes live on the trees for support & obtain sunlight & moisture.

Mutualism

Interaction where both species benefits.

Sea anemone & hermit crabs. Sea anemone gets transport & new food, anemone provide camouflage & protection by its stinging cells.