Biology in the 21st Century

Biological Questions

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What is science?

Science is… The continual effort to

discover and increase human understanding of how reality works.

The systematic process allows us to better understand past events and predict future events of a similar kind.

Science is not static, it is ever changing.

What do you think?

Define the following…FactHypothesisLaw Theory

Fact

A scientific fact is a controlled, repeatable and/or rigorously verified observation, probability of “truth” is incredibly high—little room for doubt. An example of current

facts: All things with mass

have gravity. Gravity is an attractive

force.

Fact

Sometimes new discoveries make us have to re-evaluate and/or revise our “facts” – THAT’S SCIENCE!

Former Facts There are three states

of matter. The Earth is flat.

Hypothesis

A suggested explanation; a proposal based on reason that predicts a possible correlation between multiple phenomena (incidents, events, observations, etc.)

Law

Notes only that something happens, happens consistently and across the universe; usually simply stated; frequently can be stated mathematically.

Example: Newtons 2nd Law: F = ma

A body of mass (m) subject to a force (F) undergoes an acceleration (a) that has the same direction as the force and a magnitude that is directly proportional to the force and inversely proportional to the mass.

Theory

Notes why something happens, explains why laws and facts are true, a framework about a class or group of phenomena, sometimes valuable to predict. Theories are never “proven”—

they are confirmed by overwhelming data, all theories, like all ideas in science, are subject to correction.

Theory

Examples: Plate Tectonic Theory Atomic Theory of Matter Germ Theory of Disease Music Theory Gravitational Theory Theory of Molecular

Genetics Theory of Natural

Selection

Diversity of Life

Life is found almost everywhere on earth. There are organisms

that live in hydrothermal vents in the deepest part of the ocean, in thousands-of-years-old Antarctic ice.

The Biosphere

All living things and all the places they are found on Earth make up the biosphere.Every part of the

biosphere is connected to another.

Biodiversity

The variety of life in the biosphere is biodiversity. Greater biodiversity is usually

found near the equator. Why do you think this is?

Over 2 million species have been identified, but scientists estimate that tens of millions of species are left to be identified. Every year, biologists

discover about 10,000 new species.

Characteristics of Living Things

Biology is the scientific study of all forms of life, or all types of organisms.

An organism is any individual living thing. Which of these is a

living thing? Why is it living and the other non-living?

Characteristics of Living Things

All living organisms share these characteristics: They are made of cells. They need energy. They respond to their

environment. They reproduce and grow. They maintain a stable

internal environment. They change over time.

Unifying Themes Biology has several

unifying themes: All levels of life have

systems of related parts. Structure and function are

related in biology. Organisms must maintain

homeostasis to survive in diverse environments.

Adaptation over time explains the unity and diversity of life.

Biology is a Process of Inquiry

Scientific thinking begins with observation. Observation uses the

senses—hearing, sight, smell, etc.

It involves repeatedly recording the information over time.

Thinking Like a Scientist

Over time, data is gathered. Qualitative data =

descriptions and involves characteristics that can’t usually be counted.

Quantitative data = expressed as numbers, obtained by counting or measuring.

Thinking Like a Scientist

From a large amount of data—an Inference is made. An Inference is a

logical interpretation of phenomena

It is based on prior knowledge or experience.

Explaining and Interpreting Evidence

After initial observations—a scientist will from one or more Hypotheses.

A hypothesis is: Based on prior knowledge Based on inference Informed Creative and Imaginative TESTABLE!

Controlled experiments Collecting more data

Spontaneous Generation

Up until the late 1800’s some people believed that life generated from non-life.

Redi’s Experiment

OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat.

HYPOTHESIS: Flies produce maggots.PROCEDURE

Controlled Variables:jars, type of meat,location, temperature,time

Manipulated Variables:gauze covering thatkeeps flies away from meat

Uncovered jars Covered jars

Several days pass

Maggots appear No maggots appearResponding Variable: whether maggots appear

CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur.

Spallanzani’s Experiment

Spallanzani tested Redi’s results with an experiment of his own.

Gravy is boiled. Flask isopen.

Gravy is teeming with microorganisms.

Gravy is boiled.Flask issealed.

Gravy is free of microorganisms.

Pasteur’s Experiment

Broth is boiled. Broth is free ofmicroorganismsfor a year.

Curved neckis removed.

Broth is teeming with microorganisms

Modern Tools of Biology

Microscopes Medical Imaging Modeling on

computers Molecular Genetics

The study and manipulation of DNA.

Genomics = the study and comparison of genomes within and across species.

Biology and Your Future

Food 70-75 % of processed

food contains some genetically engineered ingredients.

45% of U.S. corn is genetically engineered.

60% of adults in the U.S. are overweight or obese.

Biology and Your Future

Environment and health Recent studies have

indicated that chemicals present in re-used water can cause hormonal deformities in certain plant and animal species.

It has been suggested that hormones present in certain meat products can cause children to hit puberty quicker.

Biology and Your Future

Biotechnology Includes the use of

microorganisms to make bread and cheese.

Used in medicine, agriculture, forensic science, and many other fields.

The use of DNA testing in criminal courts is an example of biotechnology.

Biology and Your Future

Transgenic Organisms Organisms that have genes from

more than one species, or have altered copies of their own genes are transgenic organisms.

Transgenic bacteria is used to create insulin that treats diabetes.

Transgenic cows and sheep create antibodies and proteins that humans can use.

Transgenic plants are resistant to insects and can reduce or end the need of pesticides.

Biology and Your Future

Genetic Screening These tests can indicate whether

individuals or their potential offspring may be at risk for certain diseases or genetic disorders.

This can help with early diagnosis and treatment.

Who should have access to the information? What genetic quirks should be considered disorders? Could genetic information be used to design children?

Science as a Way of Knowing

Science is not a collection of immutable truths.

Science is an ongoing process.

Scientists need to be skeptical, open minded, and analytical.

Science and human values often intersect. The knowledge we collect today affects the lives of people tomorrow.