Nutrition: a complex process

Nutrition is the process by which we obtain nutrients, water and oxygen; expel carbon dioxide and waste substances through urine and sweat, and we transport all these substances to and from the cells in our body.

As we can see, nutrition is a complex process which consists of 4 basic life processes, which are carried out by 4 different systems or sets of organs:

 1. Digestion: this process allows us to get the nutrients and water we need from food and drink. 

 2. Breathing (Respiration): This process allows us to take oxygen from the air and expel carbon dioxide.

 3. Circulation: this process allows us to transport nutrients and oxygen to our body cells and waste substances and carbon dioxide that our cells must eliminate.

 4. Excretion: this process allows us to expel waste substances through urine and sweat.

JUST FOR FUN!
Do you know how many different systems carry out their functions in our body? Can you guess?
Have a look at this amazing video and find out!

Review: Plant kingdom and Animal classification. Online activities

Here you have some online activities to review Science


Plant Kingdom       


Photosynthesis 
 

Animal Classification

Plant Kingdom: nutrition, interaction and reproduction. The classification of plants

Plant kingdom

Plants are multicellular organisms with eukaryotic cells. Unlike animals, plants cannot move. Their cells have a cell wall and chloroplasts, which contain a green pigment called chlorophyll, which is involved in photosynthesis.

As all living things, plants carry out the three basic life processes:

 - Nutrition: plants can make their own food through a process called photosynthesis, in which plants use the light from the Sun.

 - Interaction: plants cannot move but they interact with the world around them by growing towards light and water and by opening and closing their leaves and petals.

 - Reproduction: some plants reproduce by spores and others reproduce by seeds. 

Watch this video to learn more about Nutrition in plants: the process of Photosynthesis

According to the way they reproduce, we can classify plants into Non-seed plants (mosses and ferns) and seed plants (gymnosperms and angiosperms)

1. Non-seed plants: they reproduce by producing cells called spores that grow into a new plant.

Mosses

Ferns

Did you know?

2. Seed plants: they reproduce by producing seeds that grow into a new plant.

A) Gymnosperms: they do not produce flowers or fruits, the seeds are grouped  in cones. 

 

B) Angiosperms: they produce flowers and fruits which contain the seeds.


Examples of Angiosperms

  

      Seeds in flower and fruit.                      Parts of a flower

Here you have a video to understand the differences between gymnosperms and angiosperms better

Learning more about... Algae

Algae are simple organisms that belong to the Protist kingdom. 

Although they may look like a plant, algae are completely different living things because they do not have the cell and tissue structure of plants.  Algae do not have the same structures that land plants do, such as leaves, roots and other organs. The largest and most complex marine algae are called seaweeds, which are multicellular. Unicellular algae are often called phytoplankton.

Parts of seaweeds

The main characteristics of algae are: 

They have eukaryotic cells, which means that they have a nucleus and organelles.They can be unicellular or multicellular. 

Chlorella (unicellular algae)

Diatoms (unicellular algae)

Giant Kelp (Macrocystis pyrifera, multicellular brown algae)

They are autotrophic, which means that they can produce their own food by photosynthesis.
They produce oxygen that is returned to the atmosphere.They have different sizes:  from microscopic to hundreds of metres in lengthThey do not have the tissues and organs of plants: they do not have true roots, stems, or leaves. Most algae are aquatic, although some are found in soil or on trees when there is enough moisture. They can be found in freshwater, marine, and moist soil habitats.They have chlorophyll and other pigments for carrying out photosynthesis. Depending on the pigments they have, algae have different colours. The three main colours are:

Red algae (Palmaria palmata, Dulse)

Brown algae (Fucus vesiculosus, Bladderwrack)

Green algae (Ulva lactuca, Sea lettuce)

Did you know? Many algae are beneficial to humans!

Here you have some videos to learn more about these amazing living things:

INTERESTING FACTS ABOUT ALGAE

INTRODUCTION TO ALGAE

UNDERWATER KELP FORESTS

Animal Classification

There are many different animals in the world. 

Animals can be classified into different groups that share common characteristics. The two main groups of animals are Vertebrates and Invertebrates. 

Watch this video to learn more about them:

VERTEBRATES are animals that have a spinal cord or backbone. They can be further classified into five groups or classes: fish, amphibians, reptiles, mammals and birds. 

Watch these videos to learn more about vertebrates and their classification:

Most of the animals in the world are INVERTEBRATES.  These animals do not have a spinal cord or backbone. Most invertebrates are oviparous, and we classify them into six main big groups: Porifera (sponges), Cnidarians (jellyfish and corals, previously called Coelenterates), Annelids (segmented worms), Molluscs, Echinoderms and Arthropods.  

Watch this video to learn more about invertebrates and their classification:

_________________________________________________________________________________

Do you want to learn more??

The largest animal group on the planet is ARTHROPODS.

Remember these animals are a group of invertebrates. All arthropods have jointed legs. Another fascinating characteristic that they all have in common is that their body is divided into segments, and many of which, though not all, are protected by an external skeleton or exoskeleton that is used as a shield or shell. Some arthropods bodies do not grow at the same rate as their exoskeleton, therefore making them shed it for a bigger size, a process known as molting.

Here you have a video to learn more about these amazing group of animals, which includes insects (6 legs, ants and butterflies), arachnids (8 legs, spiders and scorpions), crustaceans (10 legs, crabs and shrimp) and myriapods (more than 10 legs, centipedes)

Insects

Arachnids

Crustaceans

  

Myriapods

                      

Review and Extension: the Classification of Living Things. From Species to Kingdoms.

Hello kids! Some of you seem to be very interested in learning more about the classification of living things, so I have prepared this post for you! 

The Classification of Living Things. From Species to Kingdoms:

    There are so many living things on Earth that scientists have developed different systems in an attempt to classify them. 
      Living things are classified depending on how many cells they have, whether their cells are simple (prokarotic cells = they do not have a nucleus) or complex (eukaryotic cells = they have a nucleus), and how they get the nutrients they need to live.

    A SPECIES is a specific type of animals, such as cats, butterflies or apple trees. Their scientific name is made up of two or three words in Latin (Genus + species). 

     Living things that are closely related are grouped into FAMILIES: domestic cats, lions, tigers and leopards belong to the same family, the felines.

          

Felis catus (domestic cats)

Panthera leo (lion)    

    

Panthera pardus (leopard)

Panthera tigris (tiger)

           

Families are grouped into ORDERS, then CLASSES, then PHYLA and then KINGDOMS.

 

           

We can do the same with any living thing. Here you have the classification of an apple tree (Malus domesticus).

     Thus, kingdoms are big groups that categorise all living things, from the tiniest bacteria to the biggest whales. Each kingdom has specific defining characteristics that help scientists classify living things.

     

The five kingdoms are: 

1. Animal kingdom: Animals are multicellular organisms, which means they have more than one type of cell. Their cells are eukaryotic cells. This means that the cells have a nucleus and organelles. Unlike plants, animals get nutrients by eating because they can’t produce energy themselves. Animals also have the ability to move, to respond to their surroundings and to reproduce sexually. The two main groups of animals are Vertebrates and Invertebrates.

VERTEBRATES (Animals that have a backbone)

INVERTEBRATES

2. Plant kingdom: Plants are also multicellular organisms with eukaryotic cells. Unlike animals, plants cannot move. Their cells have a wall cell and chloroplasts. They can make their own food through a process called photosynthesis, in which plants use the light from the Sun. We can classify plants into Non-seed plants (mosses and ferns) and seed plants (gymnosperms and angiosperms)

Non-seed plants:

Mosses

Ferns

Seed plants:

Gymnosperms: they do not produce flowers or fruits, the seeds are grouped  in cones. 

 

Angiosperms: they produce flowers and fruits which contain the seeds.

  

      Seeds in flower and fruit.                      Parts of a flower

3. Fungi kingdom:

 Fungi are multicellular or unicellular organisms with eukaryotic cells. Like plants, fungi have cell walls, but they cannot perform photosynthesis and have to absorb nutrients to get energy. We can find in this kingdom mushrooms, moulds and yeasts.

Mould on a decaying peach

     

Mould on strawberries

Microscopic image of Yeast cells

Mushrooms (Amanita muscaria) 
Be careful! It's poisonous

4. Protist kingdom: most Protists are single-celled organisms , but some are multicellular. They have eukaryotic cells. Some protists eat to get energy like animals and some use photosynthesis like plants. They always live in water. Examples of protists are algae, phytoplankton or protozoa (Paramecium, Euglena, Amoeba).

     

                                                                                                                                             

Euglena

Algae 

                                                                             

Amoeba

Paramecium

                                                                                       

               

5. Monera kingdom: Monera are single-celled organisms with prokaryotic cell.  This means that the cells do not have a nucleus or organelles. These are the simplest living things on Earth. Most living things in this kingdom are bacteria. Some of them cause serious illnesses but some are beneficial to humans. 

E. coli

Streptococcus pneumoniae

         

To understand the classification of living things better, you can watch this video about the classification of human beings.

If you like singing, here you have an amazing song to learn and practise the five kingdoms. It's always easier with music!