1. An introduction to biology with a focus on the unity and diversity of life

2. Learning goals You should understand: -What science is and how scientific knowledge is generated -What biology is and at what scales biologists study life -The diversity and unity of life -What one concept explains both the unity and diversity of life?

3. What is nature?

4. It is very natural for humans to try to know and explain nature
(to inquire about nature)

5. How would you explain this?

6. Scientists try to describe and understand the natural world.

7. Scientists try to describe and understand the natural world.
How?

8. Science is a systematic way of knowing and understanding nature.
There are two main forms of inquiry
Discovery (or descriptive) science- Describing nature through observations and then analysis of data.
Hypothesis-based science- Explaining nature by testing hypotheses (tentative answers to questions).

9. Hypothesis-based science typically uses the scientific method….
1.) Make an observation of something in nature.
2.) Frame a question that relates to your observations.
3.) Propose a testable and falsifiable hypothesis (an answer to your question).
4.) Using the hypothesis, make predictions.
5.) Devise a way to test your prediction.
6.) Assess results (do they support or refute your hypothesis).
7.) Make conclusions.
7.) Report all results and conclusions to the scientific community.

10. Did you prove your hypothesis about the lamp?
Hypothesis-based science typically uses the scientific method….
1.) Make an observation of something in nature.
2.) Frame a question that relates to your observations.
3.) Propose a testable and falsifiable hypothesis (an answer to your question).
4.) Using the hypothesis, make predictions.
5.) Devise a way to test your prediction.
6.) Assess results (do they support or refute your hypothesis).
7.) Make conclusions.
7.) Report all results and conclusions to the scientific community.
Did you prove your hypothesis about the lamp?

11. Did you prove your hypothesis about the lamp?
Hypothesis-based science typically uses the scientific method….
1.) Make an observation of something in nature.
2.) Frame a question that relates to your observations.
3.) Propose a testable and falsifiable hypothesis (an answer to your question).
4.) Using the hypothesis, make predictions.
5.) Devise a way to test your prediction.
6.) Assess results (do they support or refute your hypothesis).
7.) Make conclusions.
7.) Report all results and conclusions to the scientific community.
Did you prove your hypothesis about the lamp?
No, it would be impossible to test all alternative hypotheses (you did not reject it).
Did you prove your hypothesis?

16. The nature of science
Science is a systematic way of understanding nature.
Scientific knowledge changes.
Science does not produce “truths”. However, science produces theories.
A theory is broad in scope. It helps us make predictions about other phenomena. It is supported by a large body of evidence.

17. The nature of science Is this clear?
Science is a systematic way of understanding nature.
Scientific knowledge changes.
Science does not produce “truths”. However, science produces theories.
Is this clear?
A theory is broad in scope. It helps us make predictions about other phenomena. It is supported by a large body of evidence.

18. Biology (the study of life) at various scales

19. Biology (the study of life) at various scales
An atom is a fundamental building block of all substances, living and non-living
Stable isotope analysis
Stephen Macko

20. Biology (the study of life) at various scales

21. Biology (the study of life) at various scales
Atoms joined with other atoms to form molecules
Many researchers have shown negative health impacts of trans fats

22. Biology (the study of life) at various scales

23. Biology (the study of life) at various scales
Cell- the smallest unit of life that can survive and reproduce on its own.
James Alexander Thomson

24. Biology (the study of life) at various scales
Organismal level

25. Biology (the study of life) at various scales
An individual that consist of on or more than one cell. For multicellular organisms scientists may focus on:
Tissue-an integrated group of cells with a common structure, function, or both
Organ-a body part consisting of two or more tissues
Organ system-a group of organs that work together to perform a vital function

26. Organisms are extremely diverse
Bacteria

27. Organisms are extremely diverse
Archea

28. Organisms are extremely diverse
Eukarya

29. Biology (the study of life) at various scales

30. Biology (the study of life) at various scales
A group of individuals of the same species, interacting in a specified area.
Camille Parmesan

31. Biology (the study of life) at various scales

32. Biology (the study of life) at various scales
James Estes, UCSC
All populations in a specified area.

33. Biology (the study of life) at various scales

34. Biology (the study of life) at various scales
A community interacting with its physical and chemical environment.
Gene Likens

35. Biology (the study of life) at various scales

36. Biology (the study of life) at various scales
Biosphere-encompasses all regions of the Earth’s crust, water, and atmosphere in which organisms live.
Lisa Curran

37. Biology (the study of life) at various scales
-Biology is exciting -Life is diverse, so is the scientific study of life (Biology)

38. Seven unifying themes of biology
New properties emerge at higher levels of biological hierarchies
Emergent properties- due to the arrangement and interactions of parts, complexity increases

39. Seven unifying themes of biology
New properties emerge at higher levels of biological hierarchies
Emergent properties- due to the arrangement and interactions of parts, complexity increases
This can be at odds with the reductionist approach to studying science

40. Seven unifying themes of biology
Organisms interact with their environments, exchanging energy and matter
Matter in-CO2 and nutrients
Matter out-O2 and decomposing biomass
Energy in-light
Energy out-heat

41. Seven unifying themes of biology
What are these used for?

42. Seven unifying themes of biology
Structure and function are correlated

43. Seven unifying themes of biology
Structure and function are correlated
The idea that form and function are related would not be exemplified by which of the following examples?
a. Cells in the intestinal lining of vertebrates have many small projections that increase the surface area for absorption of nutrients.
b. Plants that live in dry areas have large roots for absorbing water.
c. Seeds that are dispersed by wind are very heavy.
d. Fish that swim rapidly have bodies that are streamlined.
e. Moles have large front paws for digging.

44. Seven unifying themes of biology
Cells are the organisms basic units of structure and function
All organisms are composed of cells
They are the lowest hierarchical level that is alive
They share certain characteristics, but can be very diverse in form and function

45. Seven unifying themes of biology
Fig. 1-13
Negative
feedback 
Excess D
blocks a step D A B C
Enzyme 1
Enzyme 2
Enzyme 3
(a) Negative feedback W
Enzyme 4 X
Positive
Enzyme 5 Y +
Enzyme 6
Excess Z
stimulates a
step Z
(b) Positive feedback
Feedback mechanisms regulate biological systems
Negative feedback-accumulation on an end product of a process slows that process
Positive feedback (less common)- end product speeds up production

46. Seven unifying themes of biology
Feedback mechanisms regulate biological systems
Which of the following examples would represent negative feedback?
a. As carbon dioxide levels rise in the blood of a mammal, the rate of breathing increases, leading to a decrease in blood levels of carbon dioxide.
b. As global temperatures rise, more ice melts, leading to greater planetary absorption of sunlight and additional temperature increase.
c. The speed of a racehorse decreases after running a mile.
d. The metabolic rate and energy consumption of grizzly bears decreases during hibernation.
e. Frog eggs hatch after five days of development at 28 degrees C but after 10 days of development at 23 degrees C.

47. Seven unifying themes of biology
The continuity of life is based on heritable info (from DNA)
DNA controls the development and maintenance of all organisms
It is similar across species

48. The core unifying theme of biology
It explains how all life forms can be so similar (ie. Possess the same genetic language and cell structure)
It also explains how life can be so diverse
“Nothing in biology makes sense except in the light of evolution”
–T. Dobzhansky

49. The core unifying theme of biology
Evolution-change in the genetic composition of a population over time
Darwin referred to evolution as decent with modification (a more parsimonious explanation for the diversity of life)
He proposed that the mechanism was natural selection
Why?
He saw that individuals in populations varied and that the variation was heritable
He saw that populations were producing more offspring than could survive
He saw that species tended to be suited to their environment
He concluded that individuals with traits that are better suited to the environment are more likely to survive and reproduce. This will lead to changes in the gene pool over time

50. The core unifying theme of biology
Evolution
a. know the difference between a hypothesis and a theory.
b. do not understand that “theory” in science is a broad, overarching concept that explains a variety of observations.
c. think scientists use the term “theory” as a synonym for “hypothesis.”
d. understand how science accumulates information about the nature of the natural world.
e. understand how to develop scientific experiments.
Theories in Science People who characterize evolution as “just a theory” show that they

51. You should understand: -What science is and how scientific knowledge is generated -What biology is and at what scales biologists study life -The diversity and unity of life -Evolution explains both the unity and diversity of life

52. Assignment: Quiz on Monday Actively read chapter 2
Matter consists of chemical elements in pure form and in combinations called compounds
An element’s properties depend on the structure of its atoms
The formation and function of molecules depend on chemical bonding between atoms
Chemical reactions make and break chemical bonds