What is ecological adaptation?

An ecological adaptation is any morphological, physiological, or behavioral trait of an organism that allows it to survive and reproduce in a habitat or ecosystem. Adaptation is a biological mechanism by which an organism gradually gets more acclimated to its surroundings.

The importance of ecological adaptation

Presently, there are approximately 8.7 million species on Earth. They can be found in a wide range of natural environments. The natural environment is a constantly changing elements of our planet. This changing environment ensures that the species that are capable of adapting survive and have an advantage over organisms that do not adapt. The competition caused by adaptations is critical to the evolution process. The changes in the structure of organisms aid in their survival in an environment. 

Types of adaptations

Structural adaptations

These are distinctive adaptive traits of an organism's body, such as color, skin, and shape. These modifications enable organisms to survive in their natural habitat or ecosystem. Animals have structural modifications that give them a competitive advantage and they exhibit a variety of structural adaptations, such as powerful claws to catch prey or dig tunnels (e.g., Mole), whale blubber for buoyancy and heat insulation, woodpecker beaks to peck into trees to find insects for food, and so on.  

Physiological adaptations

These are adaptive mechanisms found in organisms that allow them to undertake specific metabolic activities to live in their natural habitat. Animals' physiological adaptations enable them to compete, help to protect themselves from enemies, and kill their prey (e.g., venom production in snakes) and help mammals to maintain a constant body temperature.

Behavioral adaptations

These are the behaviors that an organism exhibits to survive in its natural habitat. Animal and avian migration, hibernation, and aestivation are regarded as behavioral adaptations. Animal behavioral adaptations are behaviors that give them an advantage, such as luring opposite sexes, protecting themselves, breeding, and so on. Mating rituals, such as a male peacock bird displaying his tail feathers to lure a female partner, are an example.

Adaptations in plants

Plant life, like animals, is dependent on a variety of basic survival needs. Light, air, water, nutrients, soil, and a proper climate are all required for growth. However, not every habitat provides the necessary needs. As a result, to live in such conditions, plants have evolved specific physiological, behavioral, and morphological adaptations.

Desert plants

• Desert plants have spines to avoid excessive evaporation of water.
• Succulent stems and leaves to retain moisture.
• Long, deeper roots that can take water from the Earth.
• Plants grow short to conserve energy.
• Seeds remain dormant until they get the water needed to thrive.

Aquatic plants

• Aquatic plants have adapted stems and roots for nutrient and air uptake.
• The top portion of the root partially arises from the water to allow photosynthesis.

Polar plants

• Polar plants have a small stature, hairy appendages, and a dark color.
• Because deep layers of permanently frozen ice inhibit roots from penetrating through the permafrost, only plants with shallow roots can flourish in the tundra.
• Trees retain dead leaves for insulation. 

Plants are divided into hydrophytes, xerophytes, mesophytes, epiphytes, and halophytes based on their habitats and adaptive traits.

Xerophytes

Xerophytes are plants that live in arid or xeric environments. Xerophytes are categorized into three groups based on their adaptive properties. They are ephemeral, succulent, or non-succulent.

Ephemerals are known as drought escapers and drought evaders. These plants complete their life cycle in a short period (Tribulus and Mollugo). Succulents are plants that can withstand drought. During the dry season, these plants retain water in their parts (Bryophyllum and Punta). Non-succulents are drought tolerant. They are exposed to both external and internal dryness. They have several adaptations to withstand arid circumstances (Acacia and Nerium).

Adaptations:

• The stems and leaves are wax coated or covered with thick hairs.
• In some plants, the petiole is transformed into a fleshy leaf-like structure known as a phyllode.
• The entire leaf is converted into spines (Opuntia) or reduced to scales (Asparagus).
• To reduce water loss owing to transpiration, a multilayered epidermis with a thick cuticle is present.
• Sunken-shaped stomata with hairs in the sunken pits are exclusively seen in the lower epidermis.
• The stem of succulents contains a water storage zone.

Hydrophytes

Hydrophytes are plants that live in water or moist environments. Examples include Eichhornia and Pistia.

Adaptations:

• In submerged forms, the stem is long, thin, porous, and bendable.
• Either the cuticle is completely absent or, if present, it is narrow and poorly formed.
• Hydrophytes are able to survive in anaerobic environments.
• They have specialized aerating organs.

Halophytes

Plants that grow on soils with a high salt content are known as halophytes. Rhizophora and Avicennia are two examples. Halophytes are most commonly seen around seashores and estuaries.

Adaptations:

• A unique type of negatively geotropic root known as pneumatophores (breathing roots) is combined with pneumatophores for adequate aeration. Example: Avicennia.
• The formation of a thick cuticle on the plant's aerial portions.
• Thick, succulent, and shiny leaves. Some plants are without leaves.

Epiphytes

Epiphytes are plants that grow by perching on other plants. They solely use the supporting plants for shelter and not for water or food. These epiphytes can be found in tropical rain forests. Orchids and Hanging Mosses are examples.

Adaptations:

• Aerial roots (for respiration) and clinging roots (which hold the epiphytes firmly to the surfaces of the supporting structures).
• In some, the stems are succulent (they store water) and produce pseudo-bulbs or tubers.
• Because the fruits and seeds are so small, they are mainly transported by insects, wind, and birds.
• The occurrence of a thick cuticle and depressed stomata slows transpiration significantly.

Animal adaptations

In ecology, the most important animal adaptations are fully dependent on the nature of the habitat in which they are found.

Desert animals

The desert exhibits severe temperature variations, with scorching heat during the day and freezing temperatures at night. It also has a scarcity of water bodies and receives minimal rain. However, many animals have adapted to living in the desert. Camels, foxes, jackrabbits, insects, and snakes are among the most common desert species.

Adaptations:

• Water conservation by reduced sweating: Camels can survive temperatures as high as 44°C without sweating. Cold-blooded animals have no sweat glands and depend on their surroundings to control their body temperature. 
• Water is obtained by animals from desert plants such as cacti. Some insects also extract fluids from plants, such as nectar and sap.
• Water conservation by insoluble excreta: Birds and reptiles in the desert hold water because their metabolic wastes are released in the form of uric acid, an insoluble white substance.
• Nocturnal lifestyle: In some animals, nocturnal life reduces water loss and improves osmoregulation, especially in dry biomes.
• Massive ears: Jackrabbits, for example, have extraordinarily huge ears with a network of blood arteries. When these animals snooze in the shade, their massive ears disperse the heat from their body. 

Grassland animals

Grasslands are regions where grasses are the primary vegetation. 

Adaptations:

• Anatomical adaptation: Grassland animals, such as bison, have specially adapted teeth and digestive tracts that aid in breaking down the stiff grass.
• Camouflage: Predators that attack their prey have colors that perfectly align with their surroundings. This allows them to blend in with their surroundings and sneak up on their prey.  

Animals of the Polar regions

Extreme weather and hostile environments characterize the polar regions.

Adaptations:

Dense fur: This is a key adaptive trait because it protects organisms from intense cold. Polar bears, for example, have fur that extends all over their bodies, even the soles of their feet. Fur helps to prevent slipping on the ice. The white fur of the animal aids in camouflaging it against the background of snow. This aids in predation or avoiding becoming prey.

Blubber: A thick layer of fat covers the entire body, excluding the fins and flippers of some sea mammals, such as whales and seals. This layer protects against extreme cold and improves buoyancy. They can also use this fat as food if there is no food available or when they are inactive.

Context and Applications

This topic is significant in the exams at school, graduate, and post-graduate levels, especially for

• Bachelors in Biology/Environmental science
• Masters in Biology/Environmental science

Practice Problems

Question 1: The biological mechanism in ecology that enables the organism to survive and reproduce in its habitat is called ____.

1. Migration
2. Ecological adaptation
3. Camouflage
4. None of the above

Answer: Option 2 is correct.

Explanation: In ecology, an ecological adaptation is any morphological, physiological, or behavioral trait of an organism that allows it to survive and reproduce in its appropriate ecosystem or habitat.

Question 2: What types of plants grow along seashores?

1. Hydrophytes
2. Epiphytes
3. Halophytes
4. None of the above

Answer: Option 3 is correct.

Explanation: Plants that grow on soils with high concentrations of salts are known as halophytes. Halophytes are found on the seashores and estuaries.

Question 3: A fleshy, leaf-like structure is called a _____.

1. Petiole
2. Phyllode
3. Stomata
4. None of the above

Answer: Option 2 is correct.

Explanation: In xerophytes, the petiole is adapted into a fleshy leaf-like part called phyllode.

Question 4: Which is not a trait of xerophyte among the following?

1. Wax coating
2. Phyllode
3. Cuticle
4. Clinging roots

Answer: Option 4 is correct.

Explanation: The clinging roots are an adaptation of epiphytes. Others are the adaptations of xerophytes.

Question 5: Which of the following is found in deserts?

1. Halophytes
2. Xerophytes
3. Epiphytes
4. Hydrophytes

Answer: Option 2 is correct.

Explanation: The plants that live in dry conditions are known as xerophytes.