New Unit: Adaptations and Traits

Adaptations and Traits

The student is expected to explore how structures and functions of plants and animals allow these organisms to survive in a particular environment. The student is also expected to explore the concept that some characteristics of organisms are inherited, such as the number of limbs on an animal or flower color, and recognize that some behaviors are learned in response to living in a certain environment, such as animals using tools to get food.

Key Concepts

• The structures of plants and animals are adapted to particular environments.
• Structures of some animals, such as the blubber of seals or the fur of rabbits, help some animals survive in cold weather conditions.
• Structures, such as the waxy coating of a cactus or the presence of spines instead of leaves, help some plants survive in hot, dry conditions.
• Some characteristics are inherited while others are learned in response to the environment.
• Inherited characteristics include mainly physical characteristics such as fins on a fish, stripes on a tiger, and the yellow color of a daffodil.
• Learned behaviors include using tools, such as a chimp’s use of sticks to retrieve termites from mounds or a sea otter’s use of rocks to open shellfish.

Fundamental Questions

• What are some structures and functions of animals that allow them to survive in cold weather?
• What are some structures and functions of plants that allow them to survive in hot and dry conditions?
• What does inherited mean?
• What characteristics of animals and plants are inherited?
• What behaviors of plants and animals are learned in response to the environment?

Key Concept 1: The structures of plants and animals are adapted to particular environments.

Over 150 years ago, Charles Darwin, the English Naturalist, observed that species of animals and plants that were able to survive and reproduce had adapted to the challenges of their environments. An adaptation is a physical or behavioral characteristic that helps an animal or plant survive in its environment. Some organisms are better suited for some environments than others, and for any organism in any environment, it must adapt to survive. Adaptations do not happen rapidly; they are processes of change that takes generations and generations.

For example, in the rainforest with lots of plant life, the competition is for sunlight. As a result, plants in rainforests grow taller and faster than neighboring plants to reach the sunlight. Several types of plants in rainforests have adapted to the tall canopy of trees by simply growing as vines straight up tree trunks to reach the sunlight, whereas, trees and plants in cold tundra regions must adapt instead to the constantly blowing, freezing wind in an unprotected landscape. As a result, tundra trees grow only a few inches tall and stay near the ground to avoid the howling wind. Plants are also smaller in this frigid environment to conserve energy for their short growing season.

Key Concept 2: Structures of some animals, such as the blubber of seals or the fur of rabbits, help some animals survive in cold weather conditions.

Structures are how the parts are put together on a plant or animal. Because mammals living in cold climates have to conserve body heat, they need structures that will keep their bodies warm. Seals, whales, and polar bears have blubber as an extra layer of fat under their skin that helps them insulate their bodies to adapt to freezing water temperatures. The double-layered fur on Arctic hares and polar bears are examples of cold climate adaptations that help animals insulate warm air trapped among the dense hairs in their fur.
Other cold weather adaptations include large bodies with short legs and tails to conserve body heat, large padded feet to walk on snow, and short snouts (noses). All of these structures have the function or purpose of keeping an animal warm. These adaptations are inherited traits that have been passed down through the generations to help an organism survive in its surroundings. Organisms also learn behaviors that help them adapt to their environment.

Key Concept 3: Structures, such as the waxy coating of a cactus or the presence of spines instead of leaves, help these plants survive in hot, dry conditions.

Generally, evaporation occurs on plants’ leaves due to the release of moisture here. However, water is scarce in the desert so plants, like cacti, have leaves known as spines that are adapted for only allowing a bare minimum of evaporation to be able to occur due to their shape. The spines also protect against predators looking for a water source inside the cactus. The thick areas of a cactus are actually enlarged stems coated in a waxy substance that prevents water evaporation. These stems also function as photosynthesis sites, but in a different way than most plants. Instead of opening their pores to absorb carbon dioxide during the day, which would evaporate water, the cactus waits until night when temperatures are cooler to open their pores and store carbon dioxide. During the day with pores closed, cactus use the stored carbon dioxide, combined with sunlight and water, to begin photosynthesis, thereby conserving water. Cacti can store gallons of water in their trunks for use when rain is scarce. Their root systems spread far and wide across the surface of the ground to help catch every drop of water. Every part of a plant is adapted to respond to the environment around it.

Key Concept 4: Some characteristics are inherited, while others are learned in response to the environment.

Inherited characteristics are passed from parent to offspring through reproduction. Offspring are the children, or offshoots, from a parent. The number of limbs, the color of fur, and the shape of a beak are examples of traits (internal or external characteristic or feature) that are inherited from the parent organism. These characteristics are not received after birth, but are part of the genetic code passed on to offspring during reproduction and determine internal and external structures.Behaviors, on the other hand, are movements or actions that are taught or learned after birth. Riding a bicycle, knowing where to find prey, and rolling over for a treat are examples of behaviors that are not inherited, but must be learned.

Key Concept 5: Inherited characteristics include mainly physical characteristics, such as fins on a fish, stripes on a tiger, or the yellow color of a daffodil.

Every structure, size, whether it be big or small, color, shape, and the number of parts in every plant or animal is inherited through traits passed down from parent to offspring. Every physical characteristic a living thing is born with represents an inherited trait. Although general characteristics among the same species are similar and passed on to each generation, such as all spiders have eight legs, the individual variations that make each plant or animal unique result from the random combination of genes passed down from the parents.

Key Concept 6: Learned behaviors include using tools, such as a chimp’s use of sticks to retrieve termites from mounds or a sea otter’s use of pebbles to open shellfish.

Although students have seen dogs and circus animals learn tricks, a surprising number of learned behaviors exist in the animal kingdom where rocks and sticks become useful tools.