Exercises: Major groups of living things

Name the five groups of vertebrates and give an example of an animal for each. Also state the characteristic shared by all vertebrates, which gives the group its name.

State which group each of these living things belongs to and justify each answer with a feature of the corresponding group: a frog, a sardine, a cat, a spider, a fern, and a geranium.

The diagram shows the five groups of vertebrates with a typical trait for each, but one group is missing, marked with "?". State which group it is, describe its defining characteristics, and give two examples of animals from that group.

Explain what an invertebrate is and name four groups of invertebrates with an example of an animal from each.

State which group of vertebrates each animal belongs to and which feature helped you decide: a salmon, a garter snake, an eagle, a toad, and a cow.

Explain two differences between amphibians and reptiles (think about the skin and where they lay their eggs) and give an example of each group.

Name two characteristics of birds that allow them to fly and briefly explain how each one helps.

How many legs do insects have and how many do arachnids have? Name two animals from each group and point out another visible difference between them.

From this list of animals —dog, ant, spider, earthworm, snail, jellyfish, and trout— first separate the vertebrates from the invertebrates. Then, group the invertebrates into insects, arachnids, worms, mollusks, and jellyfish, stating a feature that helped you decide in each case.

Explain the difference between mosses, ferns, and flowering plants, and give an example of each group that you could find near where you live. What type of habitat does each typically grow in?

Create a table with three columns (group, main feature, and example) and fill it in for these six groups of living things: fish, amphibians, reptiles, birds, mammals, and insects.

Classify these invertebrates into their group (insect, arachnid, mollusk, crustacean, worm, or other) and justify each choice with a feature: a scorpion, a mussel, a centipede, a shrimp, and a sponge.

Fish are adapted to life in water. Explain the role of the gills, the fins, and the streamlined body shape.

Compare a dolphin with a tuna: state which group each belongs to and explain two differences between them, thinking about how they breathe and how their young are born and fed.

Name the main parts of a flowering plant (root, stem, leaves, flower, and fruit) and explain the function of each one.

The sea urchin is named after the hedgehog ("urchin" is an old word for it), but one is a marine invertebrate and the other a mammal. Explain what this case shows about the common names of animals and compare the characteristics of both.

An explorer finds an unknown marine animal: it has a streamlined body, lacks hind limbs, moves by means of flippers, and spends its entire life underwater. However, he observes that it periodically surfaces to take in air and that it gives birth to live young which it feeds with milk. The explorer notes in his journal: "Because of its shape and because it always lives in water, it is a new species of fish." Refute his conclusion by justifying why it should be classified as a mammal, and predict what type of reproduction, fertilization, and thermal regulation (homeothermic or poikilothermic) you would expect to find in this animal.

A classmate makes the following statement: "Since sharks have a skeleton made of cartilage rather than true bone, they should be classified as invertebrates, just like squids or crabs." Refute their stance by pointing out two fundamental differences between the internal skeleton of a shark and the protective coverings or shells of invertebrates, and explain what unique internal structure places the shark within the vertebrate group.

In a stretch of a river, two protected species live together: the brown trout (a fish with gill respiration) and the Pyrenean desman (a small semiaquatic mammal that dives to hunt larvae). Due to a chemical spill, dissolved oxygen in the water drops to levels close to zero for several weeks, while the water surface and the outside air remain unchanged. Predict, with reasoning, which of the two species will suffer immediate mortality from suffocation and which will better resist the drop in dissolved oxygen, justifying your answer based on their respiratory mechanisms.