Science Review


The Science exam will cover everything we have learned up until now including:

  • Biodiversity
  • Classification
  • Food Chain
  • Solar System – The Moon, The Sun, and The Planets


Biodiversity is the variety of life. Different species make-up biodiversity. Species is a group of living organisms that can interbreed. An organism is a living thing. It can be a plant, animal or single-celled life form (bacteria). Biodiversity includes the full range of species that live in an area. There are three kinds/components of biodiversity- genes, ecosystems, and species.

Why is biodiversity important?

  • It allows us to live in a healthy and happy environment.
  • We get food, water, and material from a diverse environment.
  • Medical discoveries to cure diseases and increase our life span were made from researching plants and animal biology.
  • Biodiversity makes life liveable on earth…i.e. oxygen

Threats to biodiversity:

  • extinction… what does it mean? It is the end of an organism. extinction is a natural part of life on Earth.
  • natural shifts in the environment can cause species to go extinct – one example is the ice age
  • today, species are going extinct at a fast rate, and this is because of human activities… ex. Over exploitation, diseases, habitat loss/degradation, pollution.


There are at least five million species on Earth, and some scientists believe there could be double that number. A species is a group of animals that are more like each other than they are like any other group of animals. They can breed with each other but not with members of other species. A way of sorting through all those species is to organize them by similar properties, or characteristics. This process is called classification. The following is a list of properties for each group of animals.

Food WEB (or Food Chain)

A food chain shows how plants, animals and humans rely on each other for food. Food chains and webs form the basis of all ecosystems. It is how energy is passed from one living thing to the next.

They demonstrate the interconnectedness of all living things. The relationships between species are crucial to sustaining an ecosystem. Often the role of a particular species does not become apparent until that species is lost.

For example, some insects are responsible for pollinating particular plants, if the insects become extinct then the plants will be lost as well, any other animals that depend on those plants will then disappear, and so on.

A food chain shows the flow of food (energy) at a very simple level eg. grass –> zebra –> lion. A food web is far more detailed as it shows the flow of food (energy) between many species. Because one animal often eats multiple species a food web can become very complex.

Animals and plants are linked by food chains

  • Animals get energy and nutrients by eating other animals or plants. For example:

caterpillars eat leaves  ->  mice eat grasshoppers  ->  owls eat mice

  • These links between animals and plants are called food chains.
  • Nearly all food chains start with a green plant.

If one part of a food chain alters, the whole food chain is affected. For example, if a disease suddenly wiped out grasshoppers, it would affect mice, owls and many other animals.

Why are green plants called producers? Plants make their own food. They get their energy from the sun.

Why are animals considered consumers? They get their food from plants or other animals.

What is a predator? An animal that eats other animals. They are found at the end of a food chain.

What is a prey?  The animal—”a consumer”—that is being eaten.

The Solar System

  • The Latin word “sol” means the sun. Our Solar System consists of a central star (the Sun), the 8 planets orbiting the sun, moons, asteroids, comets, meteors, interplanetary gas, dust, and all the “space” in between them.
  • Despite all of these planets being different from each other, they can be put into two groups. One group contains the four planets closest to the SunMercury, Venus, Earth and Mars. These are known as the Inner Planets or the Terrestrial Planets.
  • The other group contains the four planets furthest from the Sun – Jupiter, Saturn, Uranus and Neptune. These are known as the Outer Planets or the Gas Giants.
  • The two groups are separated by the Asteroid Belt, a region of thousands of asteroids and chunks of rocks that orbit along with the planets around the sun. It is located between Mars and Jupiter.
  • Dwarf planets resemble planets but are not planets. They are smaller than planets and orbit around the sun. s of 2008, there are five recognized dwarf planets: Pluto, Ceres, Eris, Makemake& Haumea

The Sun

  • All planets orbit around the sun. The sun is a star, it is a big ball of gases.
  • The sun’s energy comes from nuclear fusion (where hydrogen is converted to helium) which happens in the sun’s core. This energy is released from the sun in the form of heat and light.
  • Nuclear fusion occurs when two or more atoms are joined together to make a larger atom. Stars get their power from nuclear fusion. Deep inside a star, hydrogen atoms are constantly being converted by fusioninto helium atoms.

The Moon

The Earth’s Moon is one of 96 moons in the solar system. Earth has only one moon. The biggest moon in the solar system is Ganymede.

The smooth dark areas of the moon, which are mostly basalt rock, are called marias. The big indents caused by meteorite impact found on the moon are called craters. The same side of the moon always faces the earth.

Moonlight is reflected sunlight. Half of the moon’s surface is always reflecting light. From Earth, we see different amounts of the Moon’s lit surface. The amount seen is called a “phase”

The four main shapes are:moon-14-638.jpg


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