2.11 To discuss the ways in which organisms change over time

Natural sciences

The earth and beyond

Fossils

Educator section

Memorandum

Assignment 9:

• They lived in forests earlier.
• It was not necessary for them to be able to run fast.
• Shorter legs were sufficient for survival in forests.
• Found in open plains today.
• Must be able to run fast (from enemy).
• Longer, more muscular legs help them survive.
• Used to ride and to pull carts.
• Became bigger and stronger in order to be an efficient mode of transport.

Leaner section

Content

Activity: to discuss the ways in which organisms change over time [lo 2.3]

TO SURVIVE, PLANTS AND ANIMALS CONTINUALLY NEED TO CHANGE IN ORDER TO ADAPT TO THEIR ENVIRONMENTS.

THE ENVIRONMENT, HOWEVER, ALSO CHANGS.

THIS IS WHY ANIMAL LIFE HAS CHANGED THROUGH THE CENTURIES.

• In the period of the dinosaurs the world was mainly dry and hot. The climate started changing gradually, new animals and plants evolved and others died out. When the climate became warmer and wetter, great forests of giant ferns and a variety of conifers developed. The changing world required the dinosaurs to adapt as well in order to survive. Flowering plants and blossoming trees appeared about 100 million years ago and oak and laurel forests began to grow. Birds, insects and other animals started to develop to eat the nectar and pollen provided by the flowers.
• The dinosaurs disappeared, but their descendants remained behind. When we examine dinosaur fossils it becomes clear that the crocodiles and birds are the closest living relatives of the dinosaurs. The dinosaurs were reptiles. Reptiles actually developed 300 million years ago. Even before the appearance of the dinosaurs, reptiles had developed along different lines to form different groups.

CHANGES IN ORGANISMS:

• Some creatures, e.g. the cockroach, have shown hardly any change over millions of years. Horses once were as large as a terrier and lived in forests. Nowadays they are fast long-legged animals that live on the open plains. This kind of change results from a process of natural selection.

Prehistoriese Lewe, Van den Heever et al., p. 19

ASSIGNMENT 9

• Discuss the reasons for the above adaptations of horses in your groups, to begin with. Then write a paragraph and supply at least five possible causes of this change.

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Assessment

Learning Outcome 2: The learner will know and be able to interpret and apply scientific, technological and environmental knowledge.

Assessment Standard 2.3: We know this when the learner categorises information.