All of the organisms of the same kind that interact and reproduce within an ecosystem make up a

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Growth and Development Organisms grow and develop as they get older. All of the stages in an organism’s life – from first entering the world, growing larger and developing new parts, to reproducing young of its own make up its life cycle. When the sex cells from a flowering plant are fertilized, the fertilized cell develops into a seed. Under the right conditions, the seed will germinate and start to grow. It will grow leaves and start to make its own food. It will eventually develop flowers and i s w food f educat h and Deve nd Deve ms grow and de row and All of the stages f the stages om first entering first enteri rger and develop ger and develo reproducing you oducing you life cycle. cycle. When the are fertili are fert into a s eed fruits and go on to produce new plants of frui f t the same kind. th

When multicellular organisms grow, W they usually change in size and shape. t The number of cells that makes up their T bodies increases. b

Unicellular organisms also grow and U change shape as they get older. c They usually get larger in size before T reproducing by dividing. r

Response to Change An eagle flies high in the sky. It uses its keen sense of sight to search for fish in the lake below. When it spots a fish, it dives down and catches it in its sharp talons. Spotting the fish in its environment is an example of a stimulus. The way the eagle acted when it spotted the fish is a response. All organisms respond to stimuli in their environment. A stimulus is any change that causes an organism to act in a certain way. The way an organism reacts to the stimulus is called a response. Generally, an organism will respond in a way that increases its chances of survival. A stimulus could be a change in light, temperature, sound, chemical changes to an environment or contact with other organisms. When an eagle spots prey, it responds by diving and catching it. pea plant tendril Amazing Fact! Pea plants have specialized stems, called tendrils, that curl and twine around the objects they touch as they grow. How does this response help the pea plant survive? Activity 1.6AB Regal o change that cau nge that cauuses act in a certain wa n a certain ay rganism reacts to th ism reacts h alled a response. Ge d a response sm will respond in a l respond in s its chances of surv chances of sur mulus could be a ch mulus could be ht, temperature, sou ht, temperature, hanges to an enviro hanges to an e ontact with other ontact w R educat keen n e lake down and ment is an nt is an is an way th y thhe eagle sh is a s a respon respo li in i inn their ca ca 9

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Classifying Organisms nism

Earth is home to a great diversity of rsity of of organisms. To organize and gain a better gain a better n better understanding of organisms, scientists ms, scientistsscientists classify them into groups based on the ps based on theon th features they share. The process of he process ofess naming and classifying organisms is ing organisms i called taxonomy. Scientists around the world use the nd the world us same system of classification. This allows m of classificatio scientists to describe organisms in a o describe orga precise way. This enables them to easily way. This enable share their knowledge and discoveries. heir knowledge How is classifying organisms useful? The broadest and most general group of organisms are called kingdoms. There are six kingdoms recognized by scientists: • ancient bacteria • bacteria • protists • fungi • plants • animals

u

AB Activity 1.7

All of the organisms in each kingdom share basic characteristics or traits. The chart below shows some shared characteristics of the organisms within each kingdom. The Six Kingdoms of Life Ancient Bacteria Fungi Bacteria Plants Protists Animals • unicellular • no nucleus • decomposers • can move from place to place • unicellular • no nucleus • decomposers • can move from place to place • unicellular and multicellular • nucleus • producers and consumers • some can move from place to place •unicellularandmulticellular Plantsgal le ed cleus mposers move from p ca uca iontio fe Protists Pla • unicellular and multicellular • nucleus • decomposers • cannot move from place ular•un R nicellula eus posers unicellularandmulticellu unicellular • multicellular • nucleus • producers • cannot move from place • multicellular • nucleus d • multicellular • nucleus • consumers • can move from place to place • multicellular • nucleus to place to place

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