Seminário Biologia - Artrópodes

Summary

This seminar provides an insightful introduction to arthropods, focusing on their key characteristics, exoskeleton shedding process, evolutionary origins, and ecological and economic importance. Arthropods, including insects, arachnids, crustaceans, myriapods, and chelicerates, play crucial roles in ecosystems, from pollination to food chains and population regulation. Their exoskeleton, primarily made of chitin, allows for growth through molting. Evolutionarily, arthropods have developed specialized features, making them highly successful. Economically, they contribute to agriculture, medicine, natural products, and tourism. Overall, arthropods are essential for biodiversity and human economies.

Takeaways

• 😀 Arthropods are invertebrates with jointed legs, a rigid exoskeleton, and segmented bodies.
• 😀 They are divided into five main groups: Insects, Arachnids, Crustaceans, Myriapods (Centipedes and Millipedes), and Diplopods.
• 😀 Their exoskeleton, primarily made of chitin, serves to protect them from environmental changes and predators, while also supporting muscles.
• 😀 Arthropods need to molt to grow, as their exoskeleton prevents expansion. This process involves the shedding of the old exoskeleton and the growth of a new one.
• 😀 Body segmentation in arthropods allows for specialization of body parts for various functions like movement, feeding, and reproduction.
• 😀 The nervous system of arthropods is well-developed with ganglia connected by ventral nerve cords, and their circulatory system is open with hemolymph instead of blood.
• 😀 The process of molting is triggered by reduced feeding and the formation of a new epidermis beneath the old exoskeleton, which cracks and separates.
• 😀 After shedding the old exoskeleton, arthropods expand their bodies by inflating with air or water, depending on whether they are terrestrial or aquatic.
• 😀 Arthropods evolved around 540 million years ago, sharing a common ancestor with nematodes and onychophorans, and their key evolutionary trait is the chitinous exoskeleton.
• 😀 Arthropods play a crucial ecological role by pollinating plants, controlling pests, recycling organic material, and serving as a food base for other species in marine ecosystems.
• 😀 Economically, arthropods contribute to food production (e.g., crustaceans), biological pest control, pollination, and the production of valuable natural products like silk and dyes.

Q & A

What are the main characteristics of arthropods?

Arthropods are invertebrate animals characterized by jointed legs, a rigid exoskeleton, and a segmented body. They are divided into five major groups: insects, arachnids, crustaceans, myriapods, and diplopods.

What is the function of the exoskeleton in arthropods?

The exoskeleton serves to protect arthropods from environmental changes, such as temperature fluctuations, predators, and dehydration. It also provides support for the muscles.

Why do arthropods undergo molting?

Arthropods molt because their exoskeleton is rigid, which prevents growth. The molting process allows them to shed the old exoskeleton and expand into a new, larger one.

What is the process of exoskeleton shedding called in arthropods?

The process of shedding the exoskeleton is called 'ecdysis' or molting. It begins when the arthropod increases internal pressure, either through air or water intake, or muscle contractions.

How does the new exoskeleton develop after molting?

After molting, the new exoskeleton is initially soft and vulnerable. The arthropod inflates its body with air or water to expand the exoskeleton before it hardens, providing protection.

What is the evolutionary origin of arthropods?

Arthropods evolved from a segmented marine ancestor during the early Cambrian period, approximately 540 million years ago. This ancestor likely resembled segmented worms, sharing common traits with nematodes and onychophorans.

What are some key evolutionary innovations of arthropods?

Key innovations include the development of a chitin-based exoskeleton for protection and efficient movement, and specialized appendages for tasks such as feeding, defense, and environmental sensitivity.

What is the ecological role of arthropods in ecosystems?

Arthropods play various ecological roles, such as pollination, serving as food for other animals, decomposing organic matter, and regulating populations of other species. They are essential in maintaining ecological balance.

How do arthropods contribute to agriculture?

Arthropods, particularly insects like bees and butterflies, are crucial for pollination, which is essential for the production of about 75% of agricultural crops. Additionally, arthropods such as ladybugs and parasitic wasps are used for natural pest control.

What are some economic uses of arthropods?

Arthropods have numerous economic applications, including the production of food (crustaceans like shrimp, crabs, and lobsters), honey, silk, and natural dyes. Additionally, arthropod venoms are researched for medicinal purposes, and insects are used in biological control to reduce pesticide use.