Problem 14 - Biology Today and Tomorrow with Physiology

Question

Match the organisms with the appropriate description. $$ \text {sponges} \quad \quad \text {a. most diverse vertebrates} $$ $$ \text {cnidarians} \quad \quad \text {b. no true tissues, no organs} $$ $$ \text {flatworms} \quad \quad \text {c.jointed exoskeleton} $$ $$ \text {roundworms} \quad \quad \text {d. mantle over body mass} $$ $$ \text {annelids} \quad \quad \text {e. segmented worms} $$ $$ \text {arthropods} \quad \quad \text {f. tube feet, spiny skin} $$ $$ \text {mollusks} \quad \quad \text {g. have specialized stinging cells} $$ $$ \text {echinoderms} \quad \quad \text {h. lay amniote eggs} $$ $$ \text {amphibians} \quad \quad \text {i. feed young secreted milk} $$ $$ \text {fishes} \quad \quad \text {j. unsegmented, molting worms} $$ $$ \text {birds} \quad \quad \text {k. first terrestrial tetrapods} $$ $$ \text {mammals} \quad \quad \text {l. tailless primates} $$ $$ \text {apes} \quad \quad \text {m. bilateral with a saclike gut} $$

Step-by-Step Solution

Answer

1-b, 2-g, 3-m, 4-j, 5-e, 6-c, 7-d, 8-f, 9-k, 10-a, 11-h, 12-i, 13-l.

Step 1: Identify descriptions

Match each organism with the given descriptions by recalling specific characteristics about each group.

Step 2: Match organisms correctly

1. Sponges: Known for lacking true tissues and organs, match with 'b.' 2. Cnidarians: Known for specialized stinging cells, match with 'g.' 3. Flatworms: Known for being bilateral with a saclike gut, match with 'm.' 4. Roundworms: Known for being unsegmented, molting worms, match with 'j.' 5. Annelids: Known for being segmented worms, match with 'e.' 6. Arthropods: Known for having a jointed exoskeleton, match with 'c.' 7. Mollusks: Known for having a mantle over body mass, match with 'd.' 8. Echinoderms: Known for tube feet and spiny skin, match with 'f.' 9. Amphibians: Known as the first terrestrial tetrapods, match with 'k.' 10. Fishes: Known for being the most diverse vertebrates, match with 'a.' 11. Birds: Known for laying amniote eggs, match with 'h.' 12. Mammals: Known for feeding their young secreted milk, match with 'i.' 13. Apes: Known for being tailless primates, match with 'l.'

Key Concepts

Vertebrates

Vertebrates are fascinating creatures known for having a backbone or spinal column. This group of animals falls under the subphylum Vertebrata within the phylum Chordata. Vertebrates are divided into five main classes:

• Fishes
• Amphibians
• Reptiles
• Birds
• Mammals

The presence of a spine is a key characteristic of vertebrates, providing support and a structure for muscle attachment. This feature allows these animals to exhibit greater mobility and flexibility compared to invertebrates.
Vertebrates also have a more complex nervous system, which includes a well-developed brain encased in a protective skull. This advancement in structure and function contributes to their ability to perform more sophisticated behaviors.

Invertebrates

Invertebrates are a vast and diverse group of animals that do not possess a backbone. Comprising over 97% of all animal species on Earth, they range from simple organisms like sponges and jellyfish to more complex forms like insects and mollusks.

• Sponges: No true tissues or organs
• Cnidarians: Specialized stinging cells
• Arthropods: Jointed exoskeletons
• Mollusks: Mantle over body mass
• Annelids: Segmented bodies

Invertebrates adapt to a wide variety of habitats, from deep oceans to rainforests. They have developed various methods for feeding, defending themselves, and reproducing.
This group showcases a tremendous range of structural and functional diversity, often reflecting the environments they inhabit. Despite their lack of a backbone, many invertebrates display intricate body structures and complex life processes.

Tetrapods

Tetrapods are literally four-footed animals, and they represent a major evolutionary leap from their aquatic ancestors. This group includes mammals, birds, reptiles, and amphibians. The term "tetrapod" arises from the Greek words 'tetra' meaning four and 'pous' meaning foot.
Tetrapods are especially notable for their ability to live on land. This transition from water to land was a significant moment in evolutionary history. The first terrestrial tetrapods were amphibians, evolving fins into limbs capable of supporting body weight on land. This adaptation allowed tetrapods to exploit a wide range of ecological niches.
Tetrapods breathe using lungs, a vital adaptation for living out of water, and scenarios like amniotic eggs in birds and reptiles support further independence from aquatic environments. Tetrapods exhibit varied body plans and levels of complexity, showcasing a fascinating evolutionary path.

Mammals

Mammals are a class of vertebrates known for their distinctive features such as having hair or fur, and most notably, mothers feeding their young with milk produced from mammary glands. This class is incredibly diverse, including everything from tiny shrews to massive whales.

• Mammary Glands: Used to nourish young with milk
• Endothermy: Capability to regulate body temperature
• Live Birth: Most, but not all, give birth to live young
• Complex Brain: Advanced cognitive abilities

Mammals occupy various environments across the globe, from polar regions to tropical jungles. They have developed various adaptations that allow them to thrive in different habitats, such as thick fur for insulation and specialized limbs for climbing, swimming, or running.
The mammalian brain's complexity also enables sophisticated social structures, communication methods, and problem-solving abilities. This combination of features makes mammals a particularly interesting and adaptive class of animals.