Which group includes both spiders and horseshoe crabs?
Chelicerates (Chelicerata) are a group of arthropods that includes harvestmen, scorpions, mites, spiders, horseshoe crabs, sea spiders, and ticks. There are about 77,000 living species of chelicerates. Chelicerates have two body segments (tagmenta) and six pairs of appendages.
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Which adaptation is a key characteristic of annelids?
Which adaptation is a key characteristic of annelids that greatly increases their flexibility and mobility? You find a wormlike, soft-bodied adult animal in a mudflat. It is bilaterally symmetrical, is segmented, has a true coelom, and has a complete digestive tract.
Which of the following animals display radial symmetry?
Radial symmetry is found in the cnidarians (including jellyfish, sea anemones, and coral) and echinoderms (such as sea urchins, brittle stars, and sea stars).
Which of the following is considered a likely explanation for the events of the Cambrian explosion?
Which of the following is considered a likely explanation for the events of the Cambrian explosion? Complex predator-prey relationships and increased atmospheric oxygen levels promoted animal diversification.
What group does horseshoe crabs belong to?
Horseshoe crabs are marine and brackish water arthropods of the family Limulidae and the only living members of the order Xiphosura. Despite their name, they are not true crabs or crustaceans; they are chelicerates, most closely related to arachnids, such as spiders and scorpions.
Which group of arthropods includes the spiders ticks mites and horseshoe crabs?
Chelicerates (Chelicerata) are a group of arthropods that includes harvestmen, scorpions, mites, spiders, horseshoe crabs, sea spiders, and ticks.
Are horseshoe crabs part of the spider family?
Horseshoe crabs are living fossils meaning they have existed nearly unchanged for at least 445 million years, well before even dinosaurs existed. Horseshoe crabs are not actually crabs at all, they are much more closely related to spiders and other arachnids than they are to crabs or lobsters!
Which phylum do crabs and spiders belong to?
What are the key characteristics of an annelid?
Characteristics of Annelida
- The Annelids are coelomate and triploblastic.
- They exhibit organ system level organization.
- Their body is segmented.
- They respire through their body surface.
- Nephridia are the excretory organs.
- They have a well-developed circulatory and digestive system.
What are annelids adaptations?
An earthworm has a streamlined body with no antennae or fins or arms or legs! This streamlined shape is an adaptation to living in narrow burrows underground and the need to move easily through the soil. An earthworm has circular muscles that surround each body segment.
What are key features of the annelids quizlet?
Body wall with outer circular and inner longitudinal muscle. specialization of head region into differentiated organs, such as tentacles, palps, and eyespots of polycaetes. Capable of complete regeneration. asexual reproduction by budding in some.
Which characteristics are common to annelids only?
What are the characteristics of Annelida? Defining characteristics of annelids are that they have a complete digestive system, bilateral symmetry, and a segmented body. They are also coelomates, meaning they have a protective fluid-filled sac around their digestive system.
What is an example of radial symmetry?
Because of the circular arrangement of their parts, radially symmetrical animals do not have distinct front or back ends. They may have distinct top and bottom sides. Some examples of these animals are jellyfish, sea urchins, corals, and sea anemones. A bicycle wheel also has radial symmetry.
Which one of the following has a radial symmetry?
Radial symmetry is shown especially by sea anemones, jellyfish and slow moving organisms like starfish. Hence, option D is correct.
Do animals have radial symmetry?
Animals With Radial Symmetry Radial symmetry occurs in simple animals including the aquatic cnidarians, which include corals, jellyfish and sea anemones, and Ctenophora, which are comb jellies. A group called dchinoderms consists of starfish, sand dollars and sea urchins; these have unique five-point radial symmetry.
What is the explanation for the Cambrian explosion?
The term u201cCambrian explosionu201d refers to a hypothesized time when bilaterally symmetrical (bilaterian) animal groups of diverse forms diverged from a common ancestor during the early part of the Cambrian period, a geological period starting about 542 million years ago (Ma).
What factors caused the Cambrian explosion?
Earth system, developmental, and ecological processes have been hypothesized as isolated, singular causes of the major diversification of marine taxa early in the Cambrian. Instead, many of these processes sit within a series of cascading and nested feedback loops that together generated the Cambrian explosion.
What is an explanation proposed for the Cambrian explosion quizlet?
2)The leading hypothesis about the cause of the Cambrian explosion involves a mass extinction of Ediacaran fauna and an increase in atmospheric oxygen.
What caused the Cambrian explosion quizlet?
What were the causes of the cambrian explosion? Mass extinction ediacaran fauna followed by an adaptive radiance.
What Kingdom is a horseshoe crab in?
Horseshoe crabs are not actually crabs at all, they are much more closely related to spiders and other arachnids than they are to crabs or lobsters! There are four species of horseshoe crabs still around today.
What is a horseshoe crab related to?
Despite their common name, horseshoe crabs are not really crabs (crustaceans), but are more closely related to spiders and scorpions.
Is a horseshoe crab crustacean?
Horseshoe crabs are more closely related to spiders, ticks and scorpions than they are to true crabs. Like other arthropods, they have a hard shell, or exoskeleton, a segmented body and jointed legs
Which class of arthropods include spiders ticks and mites?
What are the 4 groups of arthropods?
Arthropods are divided into four major groups:
- myriapods (including centipedes and millipedes);
- arachnids (including spiders, mites and scorpions);
- crustaceans (including slaters, prawn and crabs).
What group of arthropods include crabs?