Animal Kingdom: Invertebrates and Vertebrates
Invertebrates
- Animals without an internal skeleton, although they may have an external skeleton or exoskeleton.
- Some groups with radial symmetry; we cannot draw a single axis that divides the animal into two symmetrical parts. Other groups with bilateral symmetry.
- Distinctive features for each sub-group (phylum).
Vertebrates
- Animals with an internal skeleton, or endoskeleton. It may be bone or cartilage.
- Animals with bilateral symmetry; that is, their body may be divided by an imaginary axis into two symmetrical parts.
- Division of the body into three distinct regions: head, trunk, and extremities.
- Tetrapod: two pairs of limbs.
- Development of a nervous system.
- Development of sense organs.
Porifera (Sponges)
- Sedentary aquatic animals, living fixed on the floor.
- No true tissues and asymmetrical.
- Body pierced by numerous pores connected by channels.
- Exoskeleton consisting of a substance called spongin.
- Filter-feeding.
- Alternating sexual and asexual reproduction.
Cnidarians (Polyps, Jellyfish, Hydra)
- Aquatic animals that live either fixed to the ground, sedentary (polyps) or free-living (jellyfish).
- With radial symmetry.
- Carnivores and carry a stinging substance, which is what stings us on the beach.
- Presence of tentacles with which they paralyze their prey.
- Polyps develop an external calcareous exoskeleton.
- Alternating sexual and asexual reproduction.
- Polyps can form colonies that can reach large areas: coral reefs, which are rich and varied ecosystems.
Annelids (Earthworms, Marine Worms, Leeches)
- Animals that can be aquatic, terrestrial, and even parasites.
- With bilateral symmetry.
- Soft, segmented body into rings.
- Digestive tract appears with mouth and anus.
- Breathing through gills or skin.
- Hermaphroditic, sexual reproduction. Oviparous.
Mollusks (Mussels, Snails, Squid, Octopus)
- Animals that can be terrestrial or aquatic.
- Soft, non-segmented body consisting of a head, visceral mass, and a muscular foot.
- Fold or cloak; in some groups, it generates a calcareous shell that acts as an exoskeleton.
- Breathing through gills or skin.
- Sexual reproduction. Oviparous.
Class Gastropods
- Shell in one piece.
- Foot well-developed; the digestive system hosts it and serves for locomotion. Terrestrial and aquatic.
- Example: Snails.
Class Bivalves
- Shell consists of two parts, valves.
- Filter feeders, marine.
- Examples: Mussels, Striped Venus, Clams.
Class Cephalopods
- A small shell called a pen.
- The presence of tentacles with suckers on the head, hence the name (cephalo: head, pods: foot). Carnivores.
- Examples: Squid, Octopus.
Arthropods (Spiders, Shrimp, Centipedes, Crickets)
- The largest group of living things; there are terrestrial, aquatic, and parasites.
- Body segmented into head, thorax, and abdomen.
- Appendices articulated: paws. The number of legs is the criterion used for classification.
- Bilateral symmetry.
- Exoskeletons that move periodically.
- Sexual reproduction. Oviparous.
Class Arachnida
- Four pairs of legs and a pair of palps, a poisonous stinger: chelicera.
- Head and thorax united to form the cephalothorax. Carnivores.
- Examples: Scorpions and Spiders.
Class Crustacea
- Five pairs of legs, the first modified into tweezers, a pair of antennae. Calcareous exoskeleton.
- Head and thorax are united into the cephalothorax.
- Segmented abdomen and appendages.
- Examples: Prawns, Lobsters, and Crabs.
Class Insects
- Three pairs of legs.
- Head with a pair of antennae, thorax segmented leaving three pairs of appendages.
- Some orders have a pair of wings, a segmented abdomen without appendages.
- Present metamorphosis.
- Examples: Grasshoppers, Flies, Bees.
Class Myriapoda
- Many pairs of legs.
- Head with a pair of antennae, the rest of the body segmented into rings with a pair of legs each (centipedes) or two pairs (millipedes). Terrestrial, some poisonous.
- Examples: Centipedes, Millipedes.
Echinoderms (Starfish, Sea Urchins, Sea Cucumbers)
- Marine. Calcareous plates; some species with bones that act as an exoskeleton.
- Radial symmetry.
- Locomotion by a hydrostatic system called the ambulacral system.
- Sexual reproduction. Oviparous.
Vertebrates: General Characteristics
Fish
- Aquatic animals or fusiform body covered with scales.
- Fins turned into limbs.
- Poikilothermic animals; that is, they are cold-blooded animals.
- Breathing through gills.
- Swim bladder that allows them to swim between different waters.
- Heart with two chambers.
- Sexual reproduction, oviparous with external development.
Class Chondrichthyes
- Cartilaginous skeleton fish without a swim bladder, internal fertilization.
- Examples: Rays, Sharks.
Class Osteichthyes
- Bony fish skeleton with a swim bladder, external fertilization.
Amphibians (Frogs, Toads, Newts, Salamanders)
- Animals with a double life; this is the name because, in the juvenile phase, they live in water. They undergo metamorphosis to become terrestrial adults in humid areas near water.
- Body naked or with very thin skin.
- Poikilothermic animals; that is, they are cold-blooded animals.
- Breathing through gills in the larval stage and lungs and skin in adulthood.
- Heart with three chambers.
- Sexual reproduction, internal fertilization, oviparous with external development.
- The first vertebrates to colonize the terrestrial environment while still depending on the water.
Order Urodela
- Amphibians with tails.
- Examples: Salamander, Newt.
Order Anura
- Tailless amphibians.
- Examples: Frogs, Toads.
Reptiles (Snakes, Turtles, Lizards, Crocodiles)
- Terrestrial vertebrates.
- Body covered with scales.
- Poikilothermic animals; that is, they are cold-blooded animals.
- Breathing with lungs.
- Four-chambered heart.
- Sexual reproduction, internal fertilization, oviparous with eggs showing development sheaths that protect and nourish the embryo and shell.
Order Crocodylia
- Develop bony plates.
- Examples: Crocodiles and Alligators.
Order Squamata
- Reptiles molt regularly.
- Body covered with horny scales.
- Examples: Lizards and Snakes.
Order Chelonia
- Body covered with a shell of bony origin.
- Examples: Turtles, Tortoises.
Birds (Eagles, Ducks, Sparrows)
- Flying animals.
- Body covered with feathers.
- Forelimbs modified for flight wings.
- Without teeth but with a beak.
- Animals homeotherms; that is, they are warm-blooded animals.
- Breathing with lungs.
- Four-chambered heart.
- Sexual reproduction, internal fertilization, oviparous with eggs showing development sheaths that protect and nourish the embryo and shell.
Mammals (Dolphin, Horse, Bat, Human Species)
- Terrestrial animals, aquatic and flying.
- Body hairy.
- Presence of mammary glands with which it is fed to the young.
- Animals homeotherms; that is, they are warm-blooded animals.
- Breathing with lungs.
- Four-chambered heart.
- Carnivores, herbivores, omnivores.
- Sexual reproduction, internal fertilization, almost all viviparous; the new animal develops inside the body and is fed through a body called the placenta. They give birth to their pups already developed.
The feathers are made of a cannon or rachis, to which are attached to the body, and a banner made up of barbs arranged on the sides of the spine. The beard out some chins that can be attached to each other.
There are different kinds of feathers:
- Tectrices: covering the entire body surface and are the bird’s protection against external agents such as rain, sun, or abrasion.
- Down: smaller than the previous ones, are free beards, and their role is to prevent heat loss.
- Remiges: are the wing feathers. The farther they insert the tip of the wing are called primary, and then insert the secondary, while those nearest the base are tertiary. All flight feathers are covered at its base by shorter feathers, arranged in series, called coverts.
- Rectrices: are the feathers that form the tail, which attach to the last caudal vertebrae. At its base are covered by the coverts above and below-flows.
- Filoplumes: hairs appear. Function tactile senses. Distributed in the contour feathers.