1. Biology in the 21st century
Biology Ch. 1

2. 1.1 The study of Life
All living things and all the places that are found on Earth make up the biosphere.
Every part of the biosphere is connected.
In the biosphere, there is a wide variety of life. This is called biodiversity.
Biodiversity increases as you move from the poles toward the equator.
There is more biodiversity near the equator because more living things are able to survive in consistent warmer temperatures than areas where the temperature fluctuates greatly.

3. A group of organisms that can reproduce by interbreeding amongst themselves is called a species.
Over half of the known species on Earth are insects.
There are about 2 million known species on Earth.
Every year new species are discovered, some species become extinct, and occasionally a species that was thought to be extinct is found again.

4. Biology is the study of life
An organism is any individual living thing
An actual definition of life is not simple because not all things can be categorized as either living or nonliving such as viruses.

5. Characteristics of All Organisms
Cells
Need for energy
Response to environment
Reproduction and development

6. All organisms are composed of cells which are the basic units of life.
Microscopic, single celled (unicellular )organisms are the most common forms of life on Earth.
Organisms composed of many cells are called multicellular.
Different types of cells have specialized functions.

7. All organisms need a source of energy for life processes.
The form of energy used by all living things is called chemical energy.
Different organisms use different forms of energy (sun, food)
In all organisms, energy is needed for metabolism.
Metabolism is all of the chemical processes that build up or break down materials.

8. All organisms must react to their environment in order to survive.
A stimulus is any factor that causes a change in organisms (light, temperature)
Members of a species must be able to reproduce in order for the species to survive.
During reproduction, organisms pass their genetic material to their offspring.
Genetic material is stored in a molecule called DNA.
Instructions for growth and development is carried on DNA and RNA.

9. 1.2 Unifying themes of biology
A system is a group of related parts that interact to form a whole.
Systems exist in all levels of biology.
Systems can also be formed by groups of organisms that interact.
An ecosystem is a physical environment with different species that interact with each other and the nonliving environment.

10. Structure and function are closely related in biology.
Structure relates to shape or form. Function refers to what it does.
Examples
Different types of teeth
Channels and enzymes
Cell types
Organs of the body

11. Organisms must maintain homeostasis in order to survive.
Homeostasis is the maintenance of constant or stable internal conditions.
Homeostasis is important because cells function best within a limited range of conditions.
Homeostasis is maintained through a process called negative feedback.
In a negative feedback system, changes in a system causes a response to return the system back to it’s original state. (Thermostat)
Homeostasis can also be maintained by changes in behavior.

12. Evolution is the term used for a change in the genetic makeup of a species over time.
Natural selection is the process that allows a species to survive.
Adaptations (changes) occur in genetic material.
Adaptations are favorable traits.
Favorable traits that are passed on from one generation to the next increase the likelihood that the species will survive and reproduce.
Adaptations may occur until a new species forms.
Adaptations occur due to changes in the environment.

13. Evolution has become a unifying theme in biology.
Biologists believe that evolution is responsible for the diversity of life.
This is believed because all organisms have similar structures and processes.

14. While natural selection can lead to new species, there is no evidence to show that this process has been responsible for creating new kingdoms of organisms.
If evolution is true then we would have to believe that all kingdoms of life came from a single organism. There is no evidence for this in the fossil record.
Also for evolution to occur, new genetic material must be added to DNA. There is evidence for new combinations of genetic material but not the creation of genetic material.
Biologists also do not have any evidence to overcome the “kind” issue and the lack of transitional forms.

15. If evolution does occur, then this is your earliest ancestor.
Cyanobacteria
If evolution does occur, then this is your earliest ancestor.

16. 1.3 Scientific thinking and processes
All scientific thinking is based on curiosity and skepticism.
Skepticism is the use of thinking to evaluate results and conclusions.
Scientific evidence in always needed in order to support or refuse ideas.

17. Scientific inquiry begins with observations which are obtained through the senses or through scientific tools.
Observations are recorded as data:
Qualitative: descriptions
Quantitative: characteristics that can be measured
A hypothesis is formed from the data
A hypothesis is a proposed answer for a scientific question
A hypothesis must be specific and testable
Hypotheses are tested multiple times (experimentation)

18. Once data from an experiment has been collected, it is analyzed to see if it supports the hypothesis.
There are 2 possible outcomes from the analysis:
Nonsignificant: data shows no effect
Significant: data shows an effect
Experimental methods and results are evaluated during a peer review
Methods, data analysis, bias
A review is needed in order for results to be accepted

19. Factors in experiments
Independent variable: condition that is changed by the experimenter (cause)
Dependent variable: measured during or after the experiment (effect)
Only one independent variable should be tested
Conditions that do not change during the experiment are called constants.
A control group is needed to compare results of the experiment
Control groups receive no change to the independent variable

20. A theory is a proposed explanation for a wide range of observations and experimental results.
Theories have to be supported by a wide range of evidence.
Theories are not easily accepted in science and are never proved.
A scientific law describes a truth that is valid everywhere in the universe.

21. 1.4 Biologists tools and technology
A microscope provides a large image of an object.
The most common type of microscope used in biology labs is the compound light microscope

22. Electron microscopes use beams of electrons instead of light to magnify an object.
They produce much higher magnifications.
They cannot be used to study living things like light microscopes.
2 types :
Scanning (SEM): scans the surface
Transmission (TEM): transmits electrons through a thin slice of a specimen

23. Bone tissue taken with scanning electron microscope.

24. An X-ray is a type of medical imaging where x-ray radiation passes through soft tissue but is absorbed by bone and teeth.
Magnetic resonance imaging (MRI) uses a strong magnetic field to produce a cross section of part of the body.
Computer models allow biologists to model a living system that they cannot study directly.
Computer models also allow biologists to manipulate variables in complex systems.
Computer models are used in the fields of epidemiology or when actual experiments are not safe, ethical, or practical.

25. The greatest leap forward in our knowledge has happened in genetics.
A gene is a segment of DNA that stores genetic information.
Molecular genetics is the study and manipulation of DNA.
Computers have been used to map the entire DNA sequence or genomes.
Genomics is the study and comparison of genomes.
Computers allow biologists to find patterns, similarities, and differences in data.

26. 1.5 Biology and your future
Biology helps us better understand health related issues such as:
Illness
Allergies
Obesity and consequences
Lifestyle choices that affect your health
Biologists also study environmental issues and how they affect species and entire ecosystems.
This is important when studying the health, interactions, and survival of species.

27. Biotechnology is the use of living things and biological processes.
Benefits
Transgenic organisms have been used to treat diseases and produce antibodies and proteins.
Genetically modified foods have increased nutrient content and insect resistance
Risks
The long term effects are not well known

28. Human genetic screening
Benefits
Risk for diseases or genetic conditions
Early diagnosis of conditions
Ethical considerations
Who should have access
How should the information be used
What should be considered a disorder
Should parents be able to choose the characteristics of their children. (Iceland)

29. Many unanswered questions:
Cure or prevention for cancer
Mutation of viruses
Storing of memories
Life on other planets