What are animal appendages?
Animal appendages are outgrowths of the body wall that are adapted for specialized functions such as feeding and locomotion. The tetrapod limb is just one type of appendage, a particular example of body wall outgrowth that played a key role in the appearance of terrestrial vertebrates in the late Devonian.
Are human legs and insect legs homologous or analogous?
A human leg appears to have little in common with an insect leg, apart from the fact that both are used for walking, so most zoologists think that the limbs of vertebrates and arthropods evolved independently and are not, therefore, homologous structures.
What are examples of homologous structures?
An example of homologous structures are the limbs of humans, cats, whales, and bats. Regardless of whether it is an arm, leg, flipper or wing, these structures are built upon the same bone structure. Homologies are the result of divergent evolution.
Are appendages present in mammals?
Most mammals are typically quadrupeds with the feet modified in many ways for terrestrial (running, hopping or leaping), fossorial (digging), arboreal (tree climbing) and aquatic living, but some have developed modified appendages such as the whales, manatees and dugongs, who have lost the rear appendages, modified the …
What is an appendage in medical terms?
(uh-PEN-dij) In medicine, a body part (such as an arm or leg) that is attached to the main part of the body.
What are appendages in the skin?
The skin appendages include sweat glands, nails, and the pilosebaceous unit of the skin, comprised of the hair shaft, hair follicle, sebaceous gland, and arrector pili muscle — these appendages derive from a down growth of the epidermis beginning in the third month of fetal life.
Which pairs of animals show homologous structures?
A common example of homologous structures is the forelimbs of vertebrates, where the wings of bats and birds, the arms of primates, the front flippers of whales and the forelegs of four-legged vertebrates like dogs and crocodiles are all derived from the same ancestral tetrapod structure.
Are sharks and penguins closely related?
Sharks, dolphins, and penguins are not closely related, but all have converged on a streamlined body form because they swim through the water.
What animals are homologous?
The arm of a human, the wing of a bird or a bat, the leg of a dog and the flipper of a dolphin or whale are homologous structures. They are different and have a different purpose, but they are similar and share common traits. They are considered homologous structures because they have a similar underlying anatomy.
Do amphibians have appendages?
They share a number of features with air-breathing lungfish, but they also differ from lungfish in many ways. One way they differ is their appendages. Modern amphibians include frogs, salamanders, and caecilians, as shown Figure below. Amphibians are the first true tetrapods, or vertebrates with four limbs.
Do reptiles have appendages?
Reptiles are tetrapod vertebrates, creatures that either have four limbs or, like snakes, are descended from four-limbed ancestors. Unlike amphibians, reptiles do not have an aquatic larval stage.
What are human appendages?
Your arm is an appendage to your body. Appendage often describes body parts, either on humans or animals. If it’s something that sticks out — like a finger, tail, or leg — chances are it can be called an appendage. In this sense, the word takes on a negative connotation: the appendage is not important.
Which is an example of a homologous appendage?
This evidence allows us surmise that these animals might have evolved from a common ancestor, which used its tripartite limbs to move. Because the wing, the fin, and the arm allow us to connect the bird, the squirrel, and the whale to a common ancestor, we can conclude that the appendages are homologous.
Which is the regulatory gene for the formation of appendages?
The expression of the Distal-less ( Dll) homeoprotein during arthropod limb outgrowth and of Dll orthologs ( Dlx) in fish fin and tetrapod limb buds led us to examine whether expression of this regulatory gene may be a general feature of appendage formation in protostomes and deuterostomes.
Where do homologous chromosomes get their genes from?
Homologous chromosomes carry one set of genes from your mother, and one set of genes from your father. The combination of these genes determines your genetic code.
How are the appendages of animals adapted to their function?
Animals have evolved diverse appendages adapted for locomotion, feeding and other functions. The genetics underlying appendage formation are best understood in insects and vertebrates.
