Lecture 18 Animal Classification Phylum Chordata The phylum

Lecture 18: Animal Classification Phylum Chordata ﺷﻌﺒﺔ ﺍﻟﺤﺒﻠﻴﺎﺕ The phylum to which we belong consists of the subphylum Vertebrata, the animals with backbones ﺍﻟﻌﻤﻮﺩ ﺍﻟﻔﻘﺮﻱ. Humans and their closest relatives are vertebrates. This group includes other mammals, birds, lizards, snakes, turtles, amphibians, and the various classes of fishes. They share several unique features including a backbone, a series of vertebrae. The phylum Chordata includes four subphyla, Subphylum : Vertebrata ﺍﻟﻔﻘﺎﺭﻳﺎﺕ Subphylum : Urochordata ﺍﻟﺬﻳﻞ ﺣﺒﻠﻴﺎﺕ Subphylum : Cephalochordata )ﺍﻟﺮﺃﺲ ﺣﺒﻠﻴﺎﺕ. Subphylum : Hemichordata ﺍﻟﻨﺼﻒ ﺣﺒﻠﻴﺎﺕ All vertebrates belong to Subphylum Vertebrata within the chordates.

Animal Types All animals are grouped as either an invertebrate or a vertebrate. 95% of all animals are invertebrate organisms. The animals do not have a backbone or vertebral column. 5% of all animals are vertebrates. These animals do have a backbone.

Section 33 -1 Diversity of Chordates

Why are fishes so successful? Adapt to environment Extract oxygen from small amounts of oxygen per unit volume Efficient locomotor structures High sensory system Efficient reproduction (produces overwhelming number of offspring)

Nutrition and Digestion Most are predators (always searching for food) Invertebrates, vertebrates Swallow prey whole Capture prey: suction-closing the opercula and rapidly opening mouth Some filter feeders- Gill rakers: trap plankton while the fish is swimming with mouth open. Some herbivores and omnivores

Reproduction and Development Ovoparous-- Lay undeveloped eggs, External fertilization (90% of bony fish), Internal fertilization (some sharks and rays) fish lay huge numbers of eggs; a female cod may release 4 -6 million eggs. Ovoviviparous- Internal development- without direct maternal nourishment-Advanced at birth (most sharks + rays)-Larval birth (some scorpeaniforms-rockfish) Viviparous- Internal development- direct nourishment from mother-Fully advanced at birth (some sharks, surf perches)

Phylum: Chordata ﺍﻟﺤﺒﻠﻴﺎﺕ Subphylum : Vertebrata ﺍﻟﻔﻘﺮﻳﺎﺕ 1 - Class Amphibia ﺍﻟﺒﺮﻣﺎﺋﻴﺎﺕ frogs (amphibian) ﺍﻟﻀﻔﺪﻋﺔ Amphibian means “two lives, ” a reference to the metamorphosis of many frogs from an aquatic stage, the tadpole, to the terrestrial adult. Tadpoles are usually aquatic herbivores with gills ﺧﻴﺎﺷﻴﻢ , a lateral line system, and swim by undulating its tail. During metamorphosis ﺍﻟﺘﺤﻮﻝ , the tadpole develops legs, and gills are replaced by lungs. Adult frogs are carnivorous hunters ﻻﺣﻢ. Most amphibians retain close ties with water and are most abundant in damp habitats.

External Structures Mucous-covered skin: protection from microorganisms, UV, desiccation, and mechanical injury. Allows for: Gas exchange, temperature regulation, and absorption/storage of water. Amphibians’ skin keeps them moist, aids in mating, can produce toxins, even change color. Sometimes it has bumps, claws warts or a sandpaper texture due to keratin buildups. All this without scales feather or hair. So how? ? With lots of glands.

Nutrition and digestion Adults Mostly carnivores feeding on invertebrates. Bullfrogs however will eat small mammals, birds, or other anurans given the chance. Hunt by sight, wait for prey to pass by Salamanders and caecilians use olfactory senses to help catch prey. Larvae Mostly herbivores http: //www. etutor. com/et 3/lessons/view/52133/print

Vocalization Usually used for mating in anurans. Attract females Mark territory Calls are species specific Can give a distress call. Hopefully enough to scare a predator into dropping the frog. Helps ensure a mate of the proper species is found.

Metamorphosis Series of abrupt structural, physiological, and behavioral changes. Anurans have the most dramatic metamorphism Limbs and lungs develop Gill are lost Tail is reabsorbed Skin thickens Head and digestive tract change to allow them to digest prey. http: //www. dnr. state. md. us/features/spring_peepers. asp