Introduction:
Natural habitats are environments where organisms live, feed, and reproduce. They are broadly categorized into aquatic and terrestrial habitats. Understanding the characteristics, adaptations, and ecological factors of these habitats is essential for the WAEC Biology examination.
Key Concepts:
1. Definition of Habitat:
- A habitat is the natural environment where an organism lives and carries out its life processes.
2. Types of Natural Habitats:
- Aquatic Habitats: Environments dominated by water, such as ponds, lakes, rivers, seas, and oceans.9as
- Terrestrial Habitats: Land-based environments, including forests, savannas, deserts, and mountains.
3. Characteristics of Aquatic Habitats:
- Salinity: Salt concentration varies between freshwater and marine habitats.
- Turbidity: Clarity of water, affecting light penetration.
- Temperature: Influences metabolic rates of aquatic organisms.
- Dissolved Oxygen: Essential for respiration in aquatic animals.
4. Characteristics of Terrestrial Habitats:
- Temperature: Varies with altitude and latitude, affecting species distribution.
- Humidity: Amount of moisture in the air, influencing plant transpiration and animal hydration.
- Soil Type: Determines the types of vegetation and, consequently, the animals present.
- Light Intensity: Affects photosynthesis in plants.
5. Adaptations of Organisms:
- Aquatic Plants: May have spongy tissues for buoyancy, breathing roots, and reduced structural support due to water buoyancy.9as+19as+1
- Aquatic Animals: Possess gills or siphons for respiration, streamlined bodies for efficient movement, and fins for navigation.
- Terrestrial Plants: Develop deep roots, thick cuticles, and reduced leaf areas to minimize water loss.
- Terrestrial Animals: Exhibit adaptations like fur for temperature regulation, limbs for locomotion, and specialized organs for water conservation.
6. Ecological Factors Influencing Habitats:
- Abiotic Factors: Non-living components like temperature, light, pH, and soil type.WAEC Online+19as+1
- Biotic Factors: Living components, including competition, predation, and symbiotic relationships.
7. Zonation in Marine Habitats:
- Littoral Zone: Area between high and low tide marks, rich in biodiversity.
- Neritic Zone: Extends from the low tide mark to the edge of the continental shelf, abundant in nutrients.
- Oceanic Zone: Open ocean beyond the continental shelf, characterized by deeper waters and fewer nutrients.
- Benthic Zone: Bottom of the ocean, inhabited by organisms adapted to high pressure and low light.
8. Importance of Natural Habitats:
- Provide shelter and resources for organisms.
- Maintain ecological balance through nutrient cycling and energy flow.WAEC Online+1Scribd+1
- Support biodiversity and ecosystem services.
Study Tips:
- Understand Definitions: Grasp the meanings of key terms like habitat, ecosystem, and adaptation.
- Differentiate Habitats: Compare and contrast aquatic and terrestrial habitats in terms of characteristics and resident organisms.Nigerian Scholars+1MySchool+1
- Focus on Adaptations: Study how specific adaptations help organisms survive in their respective habitats.9as
- Use Diagrams: Visual representations of zonation and habitat types can aid memory.9as
- Review Past Questions: Use the questions below for study and practice.
Conclusion:
A thorough understanding of natural habitats, their characteristics, and the adaptations of organisms is crucial for success in the WAEC Biology examination. Emphasizing the interplay between organisms and their environments fosters a deeper appreciation of ecological principles.
OBJECTIVES
1. The major problem experienced by organisms living in small waterbodies is
A. drying up. B. oxygen deficiency. C. scarcity of food. D. wave action.
2. Which of the following features is not an adaptation of plants to aquatic habitat?
A. Breathing roots for entry of air. B. Flowers raised above water for the purpose of pollination. C. Spongy tissues containing gases for buoyancy. D. Hairy structures on the leaves to reduce water loss.
3. In which of the following habitats is paramecium found?
A. Pond. B. Aquarum. C. lake. D. Puddle.
4. The distribution of organisms in a fresh water habitat like a stream or pond is determined by the following factors except
A. light penetration. B. pH of the soil. C. rainfall. D. temperature.
Study the diagram of the zones of a marine habitat below and use it to answer questions 5 & 6
5. In which of the zones can very few organisms be found
A. I. B. II. C. III. D. IV.
6. Which of the following factors exerts a major effect on the distribution of living organisms in the habitat?
A. Salt. B. pH. C. Light. D. Rain fall.
7. Which of the following factors is the main problem facing xerophytic plants?
A. Competition for sunlight. B. Conservation of excess water. C. Inadequate roots for water absorption. D. Lack of adequate water.
8. What is the critical limiting factor for plants below the photic zone is an aquatic ecosystem?
A. Availability of nutrients. B. Availability of water. C. Intensity of light. D. Carbon dioxide concentration.
9. Which of the following is not an aquatic habitat?
A. Estuaries. B. Ponds. C. Rainforest. D. Swamp.
10. Which of the following factors is not associated with aquatic habitat
A. Temperature. B. Light intensity. C. Turbidity. D. Humidity.
11. Which of the following best describes a marine habitat? A large body of water
A. which has no distinctive colour or taste. B. with high concentration of salt. C. with little suspended materials. D. with no water weeds.
12. Puddles, ponds, rivers, lakes, seas and oceans are grouped together as
A. ecosystem. B. biosphere. C. terrestrial habitat. D. aquatic habitat.
13. Which of the following is not classified as a terrestrial habitat?
A. Forest. B. Guinea Savannah. C. Afro Alpine. D. Littoral zone.
14. Which of the following factors is not associated with aquatic habitats
A. Salinity. B. Turbidity. C. Temperature. D. Edaphic.
15. Terrestrial organisms which are capable of maintaining their body temperature constant within fairly close limits are referred to as
A. thermoclines. B. homotherms. C. poikilotherms. D. eurytherms.
16. Which of the following factors does not affect the distribution of organisms in an aquatic habitat?
A. Turbidity. B. Depth of water. C. Humidity. D. Temperature.
17. Plants found in the aquatic habitat are generally referred to as
A. epiphytes. B. halophytes. C. xerophytes. D. hydrophytes.
18. Siphons and gills are structures in aquatic organisms used for
A. gaseous exchange. B. buoyancy. C. excretion. D. movement.
19. Which of these factors are common to both aquatic and terrestrial habitats
A. Light, rainfall and turbidity. B. Light, temperature and tide. C. Light, rainfall and temperature. D. Rainfall, turbidity and salinity.
20. Which of the following environmental factors is not considered in a terrestrial habitat?
A. Temperature. B. Sunlight. C. Humidity. D. Turbidity.
21. The distribution of organisms in a fresh – water habitat like a stream or pond is determined by the following except
A. rainfall. B. temperature. C. pH of soil. D. light penetration.
22. Which of the following organisms can be found in fresh water habitat?
A. Sargassum and dog fish. B. Red mangrove and pond skater. C. Sargassum and red mangrove. D. Spirogyra and pond skater.
23. Which of the following factors may not affect living organisms in an aquatic habitat?
A. Turbidity. B. Temperature. C. Humidity. D. Light.
The table below shows the number of some organisms in habitats W and Y. Study it and answer questions 24 and 25.
| Organism | Number in the habitat habitat W | habitat Y |
| Plankton | 126 | 0 |
| Antelope | 0 | 51 |
| Water flea | 10 | 0 |
| Tilapia | 23 | 0 |
| Lion | 0 | 6 |
| Frog | 6 | 0 |
| Grass | 0 | 250 |
24. What type of habitat is W?
A. Rainforest B. Pond C. Desert D. Ocean.
25. Which of the following statements about habitat W is correct? The
A. Absence of lions and antelopes shows that the habitat is terrestrial. B. Presence of Tilapia and planktons shows that the habitat is not aquatic. C. Type of organisms present indicate that the habitat is aquatic. D. Absence of grasses indicates that the habitat is terrestrial.
26. The number of lions and antelopes in habitat Y shows that the lion
A. is the prey while the antelope is the predator. B. is the predator while the antelope is the prey. C. and the antelope are preys to each other. D. and the antelopes are predators.
27. Rabbits cannot survive in an aquatic habitat because they have
A. no scales. B. no gills. C. fore limbs. D. lateral line.
28. Which of the following features is a characteristic of aquatic plants? Possession of
A. multiple epidermis B. heavily lignified tissue C. finely divided leaves D. succulent stem.
THEORY
1. Name two examples each of plants and animals that live in a freshwater pond.
2. What is an Estuarine habitat?
3. What is a habitat?
4. (a) State four characteristics of a salt marsh habitat. (b) Explain briefly how plants are modified for anchorage in a salt marsh habitat.
5. (a) List three major zones in the marine habitat, stating one characteristic feature of each zone. (b)(i) Give one example each of plants and animals in the marine habitat (ii) Explain how each of the plants and animals is adapted to the habitat.
6. List three factors that affect organisms in the marine habitat.
7. (a) Name two abiotic factors each which affect plants and animals in a terrestrial habitat. (b) Describe the effects of three abiotic factors on a named plant and an animal in the habitat mentioned in (a) above.
8. List five abiotic factors which affect plants in freshwater habitat.
9. State four problems that organisms in the intertidal zone of a marine habitat could encounter.
