fish

fish Fish among the plants on the sea bottom. Fig 1. Living fish are classified into two major groups or classes and one minor one. The smallest group is the Agnatha, the primitive jawless fish which includes the lampreys and hagfish. From these evolved the cartilaginous fish, the Chondrichthyes,which are further divided into three sub-classes. … Read more

Fish Groups

Water covers over three-quarters of the earth’s surface. Fish live in this world of water and are the most numerous of the vertebrates, or animals with backbones. There are three major groups of living fish. Superclass Agnatha The first group is the Superclass Agnatha. This group is the most primitive of the three groups of … Read more

How do sharks reproduce?

This is the third in our series of ‘I want to know about…’ blogs. This one will cover the topic of shark reproduction. Reproduction is vital to a species’ survival, and you’d be surprised how many different ways there are to do it. It’s ingrained into the survival instinct to reproduce and ensure that their … Read more

Anatomical Directions of Fishes — Koaw Nature

2016 – By Koaw (Image updated 2020)Whether you are a casual admirer of fishes, a serious enthusiast, or somewhere in between, it is very important to have these four basic anatomical directionalities memorized: anterior, posterior, ventral & dorsal. They also apply to most other animals within zoology. The adjacent video discusses all you need to … Read more

Alchetron, The Free Social Encyclopedia

In animal anatomy, a cloaca /kloʊˈeɪkə/ kloh-AY-kə (plural cloacae /kloʊˈeɪsiː/ kloh-AY-see or /kloʊˈeɪkiː/ kloh-AY-kee) is the posterior orifice that serves as the only opening for the digestive, reproductive, and urinary tracts (if present) of certain animals, opening at the vent. All amphibians, birds, reptiles, and a few mammals (monotremes, tenrecs, golden moles, and marsupial moles) … Read more

Wikipedia

Cloaca In animal anatomy, a cloaca (/kloʊˈeɪkə/ kloh-AY-kə), plural cloacae (/kloʊˈeɪsi/ kloh-AY-see or /kloʊˈeɪki/ kloh-AY-kee), is the posterior orifice that serves as the only opening for the digestive, reproductive, and urinary tracts (if present) of many vertebrate animals. All amphibians, reptiles and birds, and a few mammals (monotremes, tenrecs, golden moles, and marsupial moles), have … Read more