1. Chapter 1
Exploring Life

2. Video: Seahorse Camouflage
Life’s basic characteristic is a high degree of order
Each level of biological organization has emergent properties
Video: Seahorse Camouflage

3. Properties of life: (1) Order
(2) Evolutionary adaptation….such as camouflage of the seahorse in the coral
(3) Response to environment
(4) Regulation…..such as more blood flow in ears to maintain body temp
(5) Energy processing
(6) Growth & development……information inherited
(7) Reproduction

4. A Hierarchy of Biological Organization
Biosphere: all environments on Earth
Ecosystem: all living and nonliving things in a particular area
Community: all organisms in an ecosystem
Population: all individuals of a species in a particular area
Organism: an individual living thing

5. A Hierarchy of Biological Organization (continued)
Organ and organ systems: specialized body parts made up of tissues
Tissue: a group of similar cells
Cell: life’s fundamental unit of structure and function
Organelle: a structural component of a cell
Molecule: a chemical structure consisting of atoms

6. Organs and organ systems Organisms
The biosphere
Organelles
1 µm
Cell
Ecosystems
Cells
Atoms
Molecules
10 µm
Communities
Tissues
50 µm
Populations
Organs and organ systems
Organisms

7. A Closer Look at Ecosystems
Each organism interacts with its environment
Both organism and environment affect each other

8. Ecosystem Dynamics
The dynamics of an ecosystem include two major processes:
Cycling of nutrients, in which materials acquired by plants eventually return to the soil
The flow of energy from sunlight to producers to consumers (usually exits as heat)

9. LE 1-4 Sunlight Ecosystem Producers (plants and other photosynthetic
organisms)
Heat
Chemical
energy
Consumers
(including animals)
Heat

10. LE 1-6 Sperm cell Nuclei containing DNA Fertilized egg Embryo’s cells
with DNA from
both parents
Embryo’s cells
With copies of
inherited DNA
Egg cell
Offspring with traits
inherited from both parents

11. Each DNA molecule is made up of two long chains arranged in a double helix
Each link of a chain is one of four kinds of chemical building blocks called nucleotides
DNA is the heritable information & directs cell’s activities

12. Nucleus DNA Nucleotide Cell DNA double helix Single strand of DNA

13. Two Main Forms of Cells Two main forms of cells:
Eukaryotic: divided into organelles; DNA in nucleus
Prokaryotic: lack organelles; DNA not separated in a nucleus

14. LE 1-8
EUKARYOTIC CELL
PROKARYOTIC CELL
DNA
(no nucleus)
Membrane
Membrane
Cytoplasm
Organelles
Nucleus (contains DNA)
1 µm

15. The Emergent Properties of Systems
Emergent properties result from arrangements and interactions within systems
New properties emerge with each step upward in the hierarchy of biological order

16. The Power and Limitations of Reductionism
Reductionism is reducing complex systems to simpler components that are easier to study
The studies of DNA structure and the Human Genome Project are examples of reductionism

17. Systems Biology
Systems biology seeks to create models of the dynamic behavior of whole biological systems
An example is a systems map of interactions between proteins in a fruit fly cell
Such models may predict how a change in one part of a system will affect the rest of the system

18. LE 1-10
Outer membrane
and cell surface
CELL
Cytoplasm
Nucleus

19. Animation: Negative Feedback Animation: Positive Feedback
In negative feedback, the accumulation of a product slows down the process itself
In positive feedback (less common), the product speeds up its own production
Animation: Negative Feedback
Animation: Positive Feedback

20. A A Negative feedback Enzyme 1 Enzyme 1 B B Enzyme 2 C C Enzyme 3 D D
LE 1-11 A A
Negative
feedback
Enzyme 1
Enzyme 1 B B
Enzyme 2 C C
Enzyme 3 D D D D D D D D D D D

21. W W Enzyme 4 Enzyme 4 X X Positive feedback Enzyme 5 Enzyme 5 Y Y
LE 1-12 W W
Enzyme 4
Enzyme 4 X X
Positive
feedback
Enzyme 5
Enzyme 5 Y Y
Enzyme 6
Enzyme 6 Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z

22. LE 1-14
Species
Genus
Family
Order
Class
Phylum
Kingdom
Domain
Ursus
americanus
(American
black bear)
Ursus
Ursidae
Carnivora
Mammalia
Chordata
Animalia
Eukarya

23. The Three Domains of Life
At the highest level, life is classified into three domains:
Bacteria (prokaryotes)
Archaea (prokaryotes)
Eukarya (eukaryotes) Eukaryotes include protists and the kingdoms Plantae, Fungi, and Animalia

24. LE 1-15 Bacteria Protists Kingdom Plantae Archaea Kingdom Fungi
Kingdom Animalia

25. Unity in the Diversity of Life
Underlying life’s diversity is a striking unity, especially at lower levels of organization
In eukaryotes, unity is evident in details of cell structure

26. Cilia of windpipe cells
LE 1-16a
15 µm
5 µm
Cilia of Paramecium
Cilia of windpipe cells

27. Cross section of cilium, as viewed with an electron microscope
LE 1-16b
0.1 µm
Cross section of cilium,
as viewed with an
electron microscope
Cilia of Paramecium
Cilia of windpipe cells

28. Concept 1.4: Evolution accounts for life’s unity and diversity
The history of life is a saga of a changing Earth billions of years old

29. The Origin of Species articulated two main points:
Descent with modification (the view that contemporary species arose from a succession of ancestors)
Natural selection (a proposed mechanism for descent with modification)
Some examples of descent with modification are unity and diversity in the orchid family

31. Natural Selection
Darwin inferred natural selection by connecting two observations:
Observation: Individual variation in heritable traits
Observation: Overpopulation and competition
Inference: Unequal reproductive success
Inference: Evolutionary adaptation

32. LE 1-20 Population of organisms Hereditary Overproduction variations
and competition
Differences in
reproductive success
Evolution of adaptations
in the population

33. Natural selection can “edit” a population’s heritable variations
An example is the effect of birds preying on a beetle population

34. LE 1-21 Population with varied inherited traits
Elimination of individuals with certain traits
Reproduction of survivors
Increasing frequency of traits that enhance
survival and reproductive success

35. Bat wings are an example of adaptation
Natural selection is often evident in adaptations of organisms to their way of life and environment
Bat wings are an example of adaptation
Video: Soaring Hawk

37. The Tree of Life
Many related organisms have similar features adapted for specific ways of life
Such kinships connect life’s unity and diversity to descent with modification
Natural selection eventually produces new species from ancestral species
Biologists often show evolutionary relationships in a treelike diagram
[Videos on slide following the figure]

38. South American mainland
LE 1-23
Large
ground finch
Large
tree finch
Small
ground
finch
Large cactus
ground finch
Camarhynchus
psittacula
Geospiza
magnirostris
Geospiza
fuliginosa
Green
warbler
finch
Gray
warbler
finch
Sharp-beaked
ground finch
Woodpecker
finch
Medium
tree finch
Geospiza
conirostris
Medium
ground
finch
Certhidea
olivacea
Certhidea
fusca
Geospiza
difficilis
Cactus
ground finch
Camarhynchus
pauper
Cactospiza
pallida
Small
tree finch
Mangrove
finch
Geospiza
fortis
Geospiza
scandens
Camarhynchus
parvulus
Cactospiza
heliobates
Seed eater
Vegetarian
finch
Cactus flower
eaters
Seed eaters
Platyspiza
crassirostris
Insect eaters
Bud eater
Ground finches
Tree finches
Warbler finches
Common ancestor from
South American mainland

39. Video: Albatross Courtship Ritual
Video: Blue-footed Boobies Courtship Ritual
Video: Galapágos Islands Overview
Video Galapágos Marine Iguana
Video: Galapágos Sea Lion
Video: Galapágos Tortoise

40. The process of science blends two main processes of scientific inquiry:
Discovery science: describing nature
Hypothesis-based science: explaining nature

41. Types of Data Data are recorded observations Two types of data:
Quantitative data: numerical measurements
Qualitative data: recorded descriptions

43. Induction in Discovery Science
Inductive reasoning involves generalizing based on many specific observations

44. Deduction: The “If…then” Logic of Hypothesis-Based Science
In deductive reasoning, the logic flows from the general to the specific

45. A Closer Look at Hypotheses in Scientific Inquiry
A scientific hypothesis must have two important qualities:
It must be testable
It must be falsifiable

46. A Case Study in Scientific Inquiry: Investigating Mimicry in Snake Populations
In mimicry, a harmless species resembles a harmful species
An example of mimicry is a stinging honeybee and a nonstinging mimic, a flower fly

47. Flower fly (nonstinging)
LE 1-26
Flower fly (nonstinging)
Honeybee (stinging)

48. This case study examines king snakes’ mimicry of poisonous coral snakes
The hypothesis states that mimics benefit when predators mistake them for harmful species
The mimicry hypothesis predicts that predators in non–coral snake areas will attack king snakes more frequently than will predators that live where coral snakes are present

49. LE 1-27 Scarlet king snake Key Range of scarlet king snake
Range of eastern
coral snake
Eastern coral
snake
North
Carolina
South
Carolina
Scarlet king snake

50. Field Experiments with Artificial Snakes
To test this mimicry hypothesis, researchers made hundreds of artificial snakes:
An experimental group resembling king snakes
A control group resembling plain brown snakes
Equal numbers of both types were placed at field sites, including areas without coral snakes
After four weeks, the scientists retrieved the artificial snakes and counted bite or claw marks
The data fit the predictions of the mimicry hypothesis

51. (a) Artificial king snake
LE 1-28
(a) Artificial king snake
(b) Artificial brown snake that has been attacked

52. North Carolina South Carolina
LE 1-29
17%
In areas where coral snakes
were absent, most attacks
were on artificial king snakes.
83%
Key
North
Carolina
% of attacks on
artificial king snakes
% of attacks on
brown artificial snakes
South
Carolina
Field site with
artificial snakes
16%
84%
In areas where coral
snakes were present,
most attacks were on
brown artificial snakes.