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placental mammal

Primary Information
Secondary Information

Definition

Placental mammals are a group of mammals that have a placenta. A placenta is a temporary organ that develops in the uterus of a pregnant mammal. It allows the fetus to exchange nutrients and oxygen with the mother's blood.

Placental mammals are the most diverse group of mammals. They include humans, dogs, cats, cows, whales, and many other animals.

Here are some of the features that distinguish placental mammals from other mammals:

  • Placenta: Placental mammals have a placenta, which is a special organ that develops in the uterus of a pregnant mammal. The placenta allows the fetus to exchange nutrients and oxygen with the mother's blood.
  • Live birth: Placental mammals give birth to live young. This means that the young are born fully developed and able to survive on their own.
  • Mammary glands: Placental mammals have mammary glands, which produce milk to feed their young.
  • Fur or hair: Placental mammals have fur or hair, which helps to keep them warm.
  • Four-chambered heart: Placental mammals have a four-chambered heart, which allows them to pump blood more efficiently.
  • Warm-blooded: Placental mammals are warm-blooded, which means that they can regulate their body temperature.

How can the word be used?

The placenta is an important organ that allows placental mammals to give birth to live young.

placental mammal

Different forms of the word

Noun:

  • placental mammal (a mammal that has a placenta, an organ that allows the fetus to exchange nutrients and wastes with the mother's blood).

Adjective:

  • placental (of or relating to placental mammals).

Etymology

The word "placental mammal" comes from the Latin word "placenta", which means "flat cake".

The word "placental mammal" was first used in English in the 19th century. It was used to refer to mammals that have a placenta.

The root of the word "placental" is the Latin word "placere", which means "to please".

So, the word "placental mammal" literally means "mammal with a pleasing organ". This is a reference to the fact that the placenta is an important organ that allows the fetus to develop and grow.

Question

What is a placental mammal?

AQA Science Exam Question and Answer

Question:

Define what a placental mammal is and explain the significance of the placenta in their reproductive process. Provide examples of placental mammals and discuss the advantages that placental reproduction offers for these animals in terms of development and survival.

Answer:

A placental mammal is a type of mammal that gives birth to live young after a relatively long period of internal development, during which the embryo is nourished by a specialised organ called the placenta. The placenta is a vital link between the mother and the developing embryo, facilitating the exchange of nutrients, oxygen, and waste products.

Examples of placental mammals include humans, dogs, cats, elephants, and whales. Placental reproduction offers several advantages for these animals. The extended internal development within the mother's body allows for better protection and care of the developing embryo, reducing vulnerability to predators and environmental hazards during the early stages of life.

The placenta acts as a conduit for the exchange of vital substances between the mother's bloodstream and the developing foetus. Oxygen and nutrients are delivered to the embryo, while waste products are removed through the mother's circulatory system. This efficient exchange ensures that the growing foetus receives the necessary resources for optimal growth and development.