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Math 6 · Science
Living Things · Living things and their classification

The main groups of living things

On a hike along a creek in Colorado you might spot a frog, a rainbow trout and a spider. They live in different places and move in different ways. Within each kingdom we need another level of organization: the main groups.

Vertebrates

When you eat a fillet of salmon you find a central backbone, and when you touch your own back you feel a row of hard bones, but an earthworm or a jellyfish has a soft body: which internal structure divides animals into two great models of organisation?

The five groups of vertebrates drawn with a representative animal: a fish with gills and fins, a frog between water and land, a lizard with scales, a bird with feathers and a dog with hair. Vertebrates Fish gills and fins Amphibians bare skin, water and land Reptiles skin with scales Birds body covered in feathers Mammals hair and mother's milk
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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.

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.

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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,…

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.

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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…

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.

Vertebrates gills and fins tadpoles in water body covered in scales body covered in feathers hair and mother's milk fish amphibians reptiles ? mammals
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Amphibians, reptiles and adaptations

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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.

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.

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

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

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

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

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Cartilage, breathing and body temperature

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

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

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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…

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.

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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…

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.

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Invertebrates

Four invertebrates: an insect with six legs and wings, a spider with eight legs, a snail with a shell and a soft body, and an earthworm with a long, segmented body. Insects 6 legs Arachnids 8 legs Mollusks soft body Worms long, segmented body all without a backbone
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Explain what an invertebrate is and name four groups of invertebrates with an example of an animal from each.

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

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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.

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.

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From this list of animals —dog, ant, spider, earthworm, snail, jellyfish, and trout— first separate the vertebrates from the invertebrates. Then, group the invertebrates…

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.

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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…

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.

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Plant groups

Mosses do not have true roots or conducting vessels like those of vascular plants; ferns have roots, stems and leaves, but no seeds. Both reproduce by spores and their fertilization depends on water.

Seed plants include gymnosperms, such as pines, whose seeds are not enclosed in fruits, and angiosperms, such as the geranium, with flowers and seeds inside fruits. Pine cones are reproductive structures that carry naked seeds; they are not flowers and not fruits.

Four groups of plants: moss and fern, with no seeds and with spores; a pine with cones and naked seeds; a geranium with a flower and fruit. No seeds: spores With seeds cone flower fruit Mosses no true roots Ferns roots, stem and leaves Gymnosperms naked seeds Angiosperms flowers and fruits
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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…

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?

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

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

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Classifying by kinship, not by where they live

Comparison of a sea urchin, a marine invertebrate with spines, and a hedgehog, a mammal with hair and spines, which share only the name and the spines. spines spines Sea urchin Hedgehog invertebrate no backbone mammal hair and mother's milk
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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…

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.

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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 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.

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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…

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.

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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,…

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.

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Back to the beginning: The trout (fish) and the frog (amphibian) are vertebrates because they have an internal backbone, while the spider is an invertebrate (arachnid) with an exoskeleton and eight legs, showing that real kinship defines the group, not the environment where they live or how they move.

Summary

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