CHARACTERISTICS OF LIFE

Chapter 1 Lesson 1

WHAT CHARACTERISTICS DO ALL LIVING THINGS SHARE?

All living things are organized. They grow and develop. They reproduce. They respond. They maintain certain internal

conditions. They use energy.

Organisms

ORGANIZATION What is the smallest unit of life?

Cell

Unicellular Only one cellSpecialized structures

MulticellularTwo or more cellsDifferent cells perform different functions

GROWTH AND DEVELOPMENT

GrowthUnicellular

Increase in size

Multicellular Increase in number

of cells

Development Changes that

occur during lifetime Specialization of

cellsExplain the

development of a frog

REPRODUCTION Unicellular

Asexual reproduction – cell division

MulticellularSexual reproduction

RESPONSES TO STIMULI Internal stimuli

Hunger, thirst, fatigue External stimuli

Light, temperature, sights, sounds How can an external stimulus create an

internal stimulus?

HOMEOSTASIS Ability to maintain internal conditions

when outside conditions changeFever, shivering, sweating, collecting excess

water Why is maintaining homeostasis

important to organisms?Homeostasis ensures that an organism can

function. Why do you think the human body

cannot maintain homeostasis for very long in water that is less than 10 degrees C?

ENERGY Everything an organism does requires

energy.

What is the source of energy for almost all life on Earth?Almost all life on Earth gets energy from the

Sun.

From which food sources does the badger in Figure 6 get energy?The badger gets energy from the snake,

lizard, and squirrel.

What do the arrows leading to the pronghorn from the desert paintbrush and from the pronghorn to the mountain lion mean? The arrows mean that the pronghorn gets

energy feeding on the desert paintbrush, and the mountain lion gets energy by eating the pronghorn.

Why is there no arrow leading away from the mountain lion? There is no arrow leading away from the

mountain lion because the mountain lion is a top predator and is at the top of this food chain.