What is Biology?

Bio / logyLife / Study of

Using word parts:Bio logyBiosphere CosmetologyAntibiotic GeologyBiography Theology

Objective

• SWBAT identify and apply properties of living things.

What does it mean to be alive?

Properties of living things:• Exhibit structural organization• Grow and develop• Reproduce• Move• Metabolize (use nutrients and energy)• Respond to stimuli• Adapt to the environment (over time)

What about fire?

What about …

Is it alive or not controversies

• Viruses

• Prions

• Nanobots

Bell ringer 1. Assume that the abundance (quantity) of Species B is affected only by the availability of its food. Based on the table, if Species B were endangered in this stream, its survival would most likely be aided by stocking the stream with:

A. Larger plantsB. AmphipodsC. SnailsD. Water fleas

2. Based on the table, which of the 4 monitored fish species ate the greatest number of food types?

A. Species AB. Species BC. Species CD. Species D

Summary of Virus Article

Scientists disagree on whether viruses should be considered alive.

On one hand, they share a number of properties with other living things.

For example, they clearly have a structural organization and they evolve over time.

On the other hand, there is a key property they do not share: they are not made of cells.

However, scientists argue about the other properties.

Viruses may not reproduce, metabolize, grow, move, or respond to stimuli on their own, but they certainly do so in the context of their host cell.

Because viruses possess in some form so many of the properties of living things, current thinking places them right on the border of life and nonlife.

Either way, they certainly have a huge impact on human life.

Why do scientists care about the properties of living things?

• Necessary for understanding how life arose on Earth

• If we discover life somewhere besides Earth we need a way to recognize it

What is life—historical challenge

• People once believed that life arose through “spontaneous generation”—if you just left certain objects lying around they would acquire “ethers” and turn into living things.

Ethers were an invisible essence in the air.

• Idea was challenged by scientist Francesco Redi in 1698.

• Others in his day believed that maggots arose on meat through spontaneous generation but Redi believed maggots came from eggs laid on the meat by flies

The Redi Experiment

Design an experiment

• Do maggots arise on meat through spontaneous generation from “ethers” present in the air or do maggots come from eggs laid on the eggs by flies?

IV?DV?

Setup 1

• One Jar contained meat and had an open top which would allow the passage of “ethers” and flies. – (maggots appeared on the meat)

Setup 2

• The second jar was covered with an airtight lid allowing the passage of neither “ethers” or flies. – (no maggots appeared on the meat)

Setup 3

• The third was covered by a screen allowing passage of “ethers”, but not flies. – (no maggots appeared on meat)

What were the controls in Redi’s experiment?

• Same type and size of meat• Same type and size of jar• Same internal and surrounding

environment

Conclusion• Since the third setup would

theoretically allow the passage of “ethers”, but no maggots appeared, it supported the hypothesis that flies were the source of the maggots.– Led to the theory of Biogenesis

• All life comes from preexisting life