Arthropods

Pronunciation

How to pronounce Arthropoda: /ɑːrˈθrɒpədə/

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Summary

Arthropoda is the largest phylum in the animal kingdom, encompassing a wide diversity of organisms characterized by jointed legs, segmented bodies, and exoskeletons made of chitin. They play vital roles in ecosystems and have significant economic importance, albeit with some being pests and disease vectors.

Physical Characteristics

Arthropods possess an exoskeleton made of chitin, segmented bodies, and paired jointed appendages. The average size of most species ranges from 2 to 25 mm, though some can be as small as 0.1 mm and others, like the Japanese Spider Crab, can reach leg spans of up to 3.8 meters.

Identification Tips

Look for jointed appendages and segmented bodies. Characteristics such as compound eyes or ocelli can aid in identifying specific subgroups. Size varies significantly among species.

Habitat

Arthropods inhabit almost every habitat on Earth, including marine, freshwater, and terrestrial environments.

Distribution

Arthropods are cosmopolitan and are found worldwide.

Diet

Arthropods have diverse diets; many are herbivores, some are carnivorous, while others are detritivores or parasitic. For example, insects may feed on plant materials, while crustaceans may be omnivorous.

Life Cycle

Arthropods undergo various developmental stages, often involving metamorphosis. Life cycles can vary from direct development to complex metamorphosis, including larval stages such as grubs or caterpillars.

Reproduction

Most arthropods reproduce sexually, with internal fertilization commonly observed in terrestrial species. Aquatic species may employ either internal or external fertilization.

Ecosystem Role

Arthropods play crucial roles in ecosystems as pollinators, decomposers, and as a food source for numerous other animals.

Economic Impact

Arthropods contribute significantly to agriculture through pollination and serve as food sources for humans and livestock. However, some species are pests affecting crops and livestock.

Cultural Significance

Insects and other arthropods are used in cultural practices and cuisines around the world. For instance, crabs, lobsters, and edible insects are part of traditional diets in various cultures.

Health Concerns

Certain arthropod species can transmit diseases to humans and livestock, and some, like ticks and mites, may cause allergic reactions or other health issues.

Collecting Methods

• Net sweeping
• Pitfall traps
• Malaise traps
• Hand collecting

Preservation Methods

• Ethanol
• Drying
• Embedding in resin

Evolution

The evolutionary history of arthropods dates back to the Cambrian period, with a common ancestor likely exhibiting segmented bodies and biramous limbs.

Similar Taxa

• Annelids
• Onychophorans
• Tardigrades

Misconceptions

Many people mistakenly refer to all terrestrial arthropods as bugs; technically, in entomology, 'bug' refers specifically to a narrow group within the order Hemiptera.

Tags

• Invertebrates
• Biodiversity
• Ecology
• Food supply
• Pollinators