Name: Group Name: SCAVENGERS
Date Performed:
Temperature, pH, and Salinity as Limiting Factors Affecting Range of Tolerance I.
Objectives To investigate the effects of temperature ranges on the metabolism or respiratory rates of fish as well as the effects of ranging pH and salinity levels on the growth, development and survival of selected plants and animals.
II.
Data, Analysis and Discussion A. The observed effects of temperature on opercular movement. TEMPERATURE 10-15°C Normal/Control 35-40°C
Rate of opercular movement per 3 minutes 43 139 161
B. The observed effects of pH changes on the morphology and behavioral responses in guppies. pH levels Responses Breathing Responses Swimming Movements Body Color Size Changes
2.0
6.0
7.0
8.0
10.0
Slow
Fast
Normal
Fast
Slow
Fast
Normal
Fast
Fast
Fast discoloration bloated
(swimming around)
slight discoloration semibloated
Normal Normal
(swimming around)
slight slight discoloration discoloration semisemibloated bloated
C. Effects of pH changes on the mortality rate of guppies after 3 minute exposure to various pH levels pH Levels 2.0 6.0 7.0 8.0 10.0
Number or dead guppies 4 2 0 2 3
% Mortality 100% 50% 0% 50% 75%
D. Effects of salt stress on freshwater snails after 3-4days exposure Salt Solutions 0.0 2.5 5.0 10.0 20.0
No. of dead guppies 0 (4 days) 1(3 days) 2(3 days) 3(2 days) 3(2 days)
E. Effects of Salinity on the percentage germination of corn seeds Salt Solutions 0.0 2.5 5.0 10.0 20.0
No. of Seeds Germinated 10 4 1 0 0
% Germination 100% 40% 10% 0% 0%
F. Effects of salinity R/S ration in corn seeds Salt Solutions 0.0 2.5 5.0 10.0 20.0
Average Shoot Length 4.27 cm 2.75 c 1.21 cm 0 0
Average Root Length 7.51 cm 6.275 0.5 cm 0 0
R/S Ratio 1.75 2.28 0.41 -
Description of Materials and Specimen Catfishes (Clarias batrachus) are a diverse group of ray-finned fish, named for their prominent barbels, which resemble a cat's whiskers. The catfishes were brought alive, slimy and active. The guppies (Poecilia reticulata), also known as million fish and rainbow fish are both from a street pet vendor. Guppies are used as a model organism in the field of ecology, evolution, and behavioral studies. Freshwater snails (Pomacea canaliculata) is one kind of freshwater mollusc. They were gathered from rice fields. Corn seeds (Zea maize) are prepared by soaking overnight.
Graphs Effects of Salinity Changes in Corn
5 4 3 2 1 0 2.0
6.0
7.0 pH levels
8.0
10.0
No. of Germinated Corn
No. of Dead Guppies
Effects of pH Changes in Guppies 15 10 5 0
0.0
2,5
5.0 Salt Solutions
10.0
20.0
III.
Conclusion A limiting factor is any environmental factor that restricts the ecological niche of an organism. pH, salinity and temperature as factors can greatly affect the range of tolerance of organisms. It may hinder the organism’s growth, cause physical and metabolic changes or worst, cause death. In this experiment, we realized the importance and great effect of limiting factors to our environment and how this simple unnoticed factors cause big efffect in nature.
IV.
Answers to Guide Questions 1. Temperature has long been recognized as an important environmental factor in both terrestrial and aquatic ecosystems in observed to its key role over biological activity such as development, growth and reproduction of organisms. Mainly temperature influences enzymatic reactions through hormonal and nervous control to digestion, from respiration and osmoregulation to all aspects of an organism’s performance and behavior. If temperature to high, the binding cites of protiens are, in effect, too wide open and enzyme function is inefficient. Generally high temperature shock causes dysfunctional increases in binding sites it can causes total unfolding of the protein, producing irreversible damage. Some studies showed that the disruption of physiological integration can sometimes be observed at the cellular level by ciliary activity of epithelial cells that can be examined over a range of temperatures. 2. Van’t Hoff, a Nobel Laureate in thermo chemistry proposes that with the increase of every10 C° , the rate of metabolic activities doubles. This rule is termed to as the Van’t Hoff’Rule. Van’t Hoff’s rule can also be stated in reverse saying that the reaction rate is halved with the decrease of every10 C° . The effect of temperature on the rate of a reaction is expressed in terms of temperature coefficient of Q10 value. Q10 values are estimated taking the ratio between the rate of a reaction at X°C and rate of reaction at (X 10 C − ° ). In the living systems the Q10 value is about 2.0. If the Q10 value is 2.0, it means, for every 10 C° increase, the rate of metabolism doubles. This relationship holds only over the temperature range of normal activity, which for most organisms lies between 0°and 40°C (Thompson 1942, Schmidt-Nielsen 1997). Normal operating temperature varies among species and taxonomic or functional groups. Any given species usually operates over some subset of this temperature range, although there are exceptions. For example, most aquatic organisms do not experience temperatures above 25°–30°C, endothermic birds and mammals maintain relatively high and constant temperatures (36°–40°C), some ectotherms can tolerate only a very narrow range of temperatures, and some microbes from extreme environments such as hotsprings and hydrothermal vents can live at temperatures that approach or exceed 100°C.
3. Endotherms are animals that primarily produces its own heat. Ectotherms are animals that primarily gains heat through the environment.
Homeotherms are animals that have a constant body temperature. Poikilotherms are animals whose body temperature adjusts depending on the environment. Osmoconformer adjusts to the osmotic concentration of its surrounding so that the osmoregularity is the same at the medium. Osmoconformer maintain its own osmotic concentration regarldess of the surrounding medium. Eurytopic Organism is a plant or animal capable of living in extremely varied habitats. Stenotopic Organism is an animal or plant confined to relatively few habitats. 4.
5.
6. Water weight decreased in plants that received higher concentrations of NaCl, which shows that higher concentrations of NaCl in a plant’s environment make it more difficult for the plant to take in water causing some of the seeds to not germinate. Solutes like NaCl decrease the water potential of the water surrounding a plant, making water uptake by the plant’s cells more difficult (Parida and Das, 2005). This indicates that corn plants experiencing NaCl stress have a decrease in net photosynthesis. A corn plant under NaCl stress should create extra roots to take in the maximum amount of water possible.
