Animal nutrition

1. Feeding and digestion in animals Animals are heterotrophic; they need to find food and transform it to get nutrients. These substances provide energy and materials the animal needs to grow, make new tissues and control cellular activity. [...]

Animals are heterotrophic organisms; they cannot make the organic material they need to eat. They can get organic material from other animals and from plants. Plants are the only living things that can produce organic material. [...]

1.1. How do animals feed? Animals are heterotrophic; they need to find food and transform it to get nutrients. These substances provide energy and materials the animal needs to grow, make new tissues and control cellular activity. [...]

2.1. The circulatory system The circulatory system is made up of blood vessels (arteries, veins and capillaries). The heart pumps the blood through the blood vessels to reach all the cells in the body. [...]

3.1. How do cells obtain energy? In aerobic cellular respiration, nutrients break down in the presence of oxygen and gradually release their energy. This process generates carbon dioxide (figure 1). [...]

Diffusion In unicellular organisms, like the amoeba, respiratory gases are exchanged across the whole surface of the body. These gases then cross the cell membranes by diffusion. [...]

4.1. What does excretion consist of? Cell activity produces waste products like carbon dioxide or urea. These substances are toxic for the organism if they accumulate. [...]

Animals are heterotrophic organisms; they cannot make the organic material they need to eat. They can get organic material from other animals and from plants. Plants are the only living things that can produce organic material. [...]

Animals are heterotrophic organisms; they cannot make the organic material they need to eat. They can get organic material from other animals and from plants. Plants are the only living things that can produce organic material. [...]

Animals are heterotrophic organisms; they cannot make the organic material they need to eat. They can get organic material from other animals and from plants. Plants are the only living things that can produce organic material. [...]

Animals are heterotrophic organisms; they cannot make the organic material they need to eat. They can get organic material from other animals and from plants. Plants are the only living things that can produce organic material. [...]