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Classification of Living Things - Vertebrates and Invertebrates

Grade 6IB

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Classification is the process of grouping living organisms based on shared characteristics. The primary system used is the Linnaean system, which organizes life from Kingdom down to Species.

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Vertebrates are animals that possess a backbone or vertebral column. They belong to the phylum Chordata. This group includes five main classes: Mammals, Birds, Reptiles, Amphibians, and Fish.

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Invertebrates are animals that do not have a backbone. They make up approximately 97%97\% of all animal species on Earth. Major groups include Arthropods, Mollusks, Annelids, and Cnidarians.

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Body temperature regulation is a key characteristic. Endothermic (warm-blooded) animals maintain a constant internal temperature, while Ectothermic (cold-blooded) animals rely on external heat sources. This can be expressed in degrees Celsius (∘C^\circ C) or Fahrenheit (∘F^\circ F).

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Binomial Nomenclature is the scientific naming of species using two parts: the Genus (capitalized) and the Species (lowercase), such as Panthera leoPanthera\ leo for a lion.

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The respiration process in all living things involves the conversion of glucose and oxygen into energy, represented by the chemical equation: C6H12O6+6O2→6CO2+6H2O+EnergyC_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + Energy.

📐Formulae

T(∘F)=T(∘C)×95+32T(^\circ F) = T(^\circ C) \times \frac{9}{5} + 32

C6H12O6+6O2→6CO2+6H2O+EnergyC_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + Energy

Total Species=∑Vertebrates+∑Invertebrates\text{Total Species} = \sum \text{Vertebrates} + \sum \text{Invertebrates}

💡Examples

Problem 1:

An animal is found to be endothermic, has feathers, and breathes through lungs. To which class of vertebrates does it belong?

Solution:

The animal belongs to the class Aves (Birds).

Explanation:

Birds are the only class of vertebrates that possess feathers and are endothermic (maintaining a stable internal temperature like 38∘C38^\circ C to 42∘C42^\circ C).

Problem 2:

Convert a lizard's body temperature of 25∘C25^\circ C to Fahrenheit to understand its metabolic state in different units.

Solution:

T(∘F)=25×95+32=45+32=77∘FT(^\circ F) = 25 \times \frac{9}{5} + 32 = 45 + 32 = 77^\circ F

Explanation:

Since lizards are ectothermic, their body temperature matches the environment. Using the conversion formula, we find that 25∘C25^\circ C is equal to 77∘F77^\circ F.

Problem 3:

Identify the invertebrate group: An organism with a soft body, often protected by a hard shell, such as a snail or an octopus.

Solution:

Mollusca (Mollusks).

Explanation:

Mollusks are characterized by a soft unsegmented body; many have a calcareous shell (CaCO3CaCO_3).

Vertebrates and Invertebrates - Revision Notes & Key Formulas | IB Grade 6 Science