life cycles

LIFE CYCLES

The life cycle of vertebrates

• Vertebrates also change in their life, they pass through different stages: infancy, adulthood and old age.

• The adult stage is the longest.

• Vertebrates reproduce when

they are adults.

• Mammals are viviparous animals: they are born from their mother’s womb.

• Birds, fish, amphibians and reptiles are oviparous: they are born from eggs.

The life cycle of invertebrates

• Invertabrates also change in their lifes.• Some invertebrates like butterflies, change a lot from one stage to another.• Invertebrates are oviparous.

Butterflies cycle

• First, the adult female lay eggs.

• Then, a larva, that looks like a worm, comes out.

• Next, the larva’s skin become hard. This is a cocoon (pupa).

• Finally, the pupa opens and a butterfly comes out.

Animals need to eat

• Herbivores eat plants

• Carnivores eat

other animals.

• Omnivores eat

plants and animals.

• Animal digest food.• Digestion begins in the mouth• Then, continues in the other organs of the

digestive system (the stomach and the intestine)

• Finally, the waste is transformed into faeces and expelled through the anus.

Animals need to breathe

• Mammals, birds and reptiles

breathe through the lungs.

• Most aquatic animals, like fish,

take in oxygen from the water

through gills.

• Some aquatic animals, like dolphins or whales, come to surface to take in oxygen with the lungs.

• Other animals, like insects, breath through a tracheal system: small tubes that carry the air to different parts of the body.

Plants

Plant reproduction

• Most plant produce flowers that become fruit.

• Inside the fruit, there are

seeds.

• The seeds fall to the ground

and a new plant grow,

this is germination.

• First, the seed absorbs water from the soil.

• Then, the seed opens and a root grows down into the

soil.

• Finally, a stem

grows up.

Other types of plant reproduction

• Some plants reproduce from stems, like bulbs and tubers.

• They are underground.

Plants make their own food

• First, the roots absorb water and mineral salts from the soil. The mixture is raw sap.

• Next, the raw sap goes up through the stem to the leaves.

• Leaves use sunlight and carbon dioxide to produce elaborated sap.

• This process is called Photosynthesis.

• Finally, the elaborated sap travels from the leaves to the other parts of the plant to be used or stored.

Plants also take in oxygen

• Plants take in air through little holes in the leaves.

• Land plants take in oxygen from the air.• Water plants take in oxygen

from water.• Plants also expell carbon

dioxide in this process.• Plants use oxygen and elaborated sap to make

energy and proteins.