Download Chapter 1 Intro

Introduction: Themes in the
Study of Life
Chapter 1
definitions
Evolution
process of change transformed life over 3.5
billion years
Biology study of living things
evidence based answers
Characteristics of life
1. Regulation
Homeostasis = internal conditions
relatively constant under
changing environmental
conditions
Ex. body temperature
2. Energy processing
• Capture, Use, Store
Heart rate max 1200 b/m
3. Growth and
Development
4. Reproduction
Produce next generation
FYI
• Female birds, rabbits, reptiles can
store sperm for months
• Tilapia (fish) brood eggs in the mouth
• Reef fish can switch sex in minutes
• Kangaroo raise young in a ventral
pouch
5. Response to environment
stimulus  response
6. Evolutionary adaptation
• Evolve over many generations
• Hereditable traits
lungfish
7. Order
Arrangement of structures
Function
Find 5 of the 7 Find the properties of
life in video on frogs
Life studied at different organizational levels
power of ten
Enhanced scale of universe
The biosphere
Cells
Organs and
organ systems
Ecosystems
Cell
Organelles
Communities
Tissues
Populations
Organisms
Atoms
Molecules
Biosphere - all
environments on Earth
that support life
What are these
environments?
The biosphere
Ecosystem - living things in
an area + nonliving
List 2 ecosystems: _______
Communities - all living
species in an ecosystem
Population - all individuals of
a species in a specific area
Organism - individual
Amoeba has
properties of life
Elephant has
properties of life
Organisms
Organ system - organs work together for specific
function
• Organ – has multiple tissue types which
function together
Tissues – group of like
cells that work together
Dermal tissue
Myocardial tissue
• Cell –basic unit of life
– Organisms unicellular or
multicellular
• Organelles – functional components of a cell
Molecules – consist of two or more
atoms
H2O
NaCl
C6H12O6
Atom– smallest unit of matter that
retains the properties of an element
Chlorophyll
C55H72O5N4Mg
Theme: Emergent properties
• Arrangement and interaction of parts in
complex organisms lead to complex properties
FYI: Emergent properties of snowflakes (physics)
Reductionism
• Study parts of system
Systems Biology
study of system
ex. a leaf, a brain
FYI: Example of systems biology
Interaction of proteins
in a eukaryotic cell
Nucleus
Themes: Organisms interact with
environments, exchanging matter, energy
1. Cycling of nutrients
Carbon cycle
2. Flow of energy
sunlight  producers  consumers  decomposers
www.bcgrasslands.org
Sunlight
ECOSYSTEM
DYNAMICS
Ecosystem
Cycling of
nutrients
and
Energy flow
Cycling
of
chemical
nutrients
Producers
(plants and other
photosynthetic
organisms)
Heat
heat
Chemical energy
Consumers
(such as animals)
Heat
Heat is a
waste product
Energy has different forms
– light, chemical, kinetic, thermal
Light  chemical ATP  motion  heat
• Theme: Structure and function correlated
– bird bones have spaces = light weight
Theme: Cells are basic unit of life
• Cells:
– Cell membrane
– DNA
– Replicate
Yeast
Bacteria
Animal
Plant
Two types of cells
Eukaryotic cell
– Membrane-enclosed organelles, and nucleus
– Plantae, Animalia, Fungi, Protista
Prokaryotic cell
– Simpler, smaller
– No nucleus or organelles
– Bacteria, Archaea
FYI: Who knew?
• 500 to 1000 species of bacteria live in the human
large intestine, skin, mouth, and other locations
• Most bacteria in the gut are anaerobes (do not use
oxygen)
• 2 species of Archaea are present in the human gut,
they are methanogens.
• No known Archaea cause disease
• Theme: The continuity of life is based on
heritable information (DNA)
• Chromosomes
– Strands of DNA
• Genes
– DNA that encodes proteins
– Proteins determine traits
Genome = all the DNA in a
cell (has all instructions)
Ce
ll
D
N
A
DNA is inherited
Before a cell divides, DNA is copied
Sperm cell
Nuclei
containing
DNA
Egg cell
Fertilized egg
with DNA from
both parents
Embryo’s cells with
copies of inherited DNA
Offspring with traits
inherited from
both parents
The human genome and others have been sequenced
http://imgs.sfgate.com/c/pictures/2004/08/30/mn_genome30gr.jpg
Theme: Feedback mechanisms
• Allow body to self-regulate
• Negative feedback
– as more of product accumulates, the process that
creates it slows and less product produced
Negative feedback: insulin action
Describe how the sweating response is negative feedback
A
–
Enzyme 1
B
D
D
Enzyme 2
D
C
Enzyme 3
D
• Positive feedback
– As more of product accumulates, the process that
creates it speeds up and more product produced
Positive feedback: uterine
contractions
W
Enzyme 4
X
+
Z
Enzyme 5
Y
Z
Z
Enzyme 6
Z
Core Theme: Evolution
“Nothing in biology makes sense except in the light of evolution”—
Theodosius Dobzhansky
All organisms living on Earth are descendants of
common ancestors
– Shared (homologous) features
• Ex. Backbone in vertebrates
Use shared features to group organisms by evolutionary relatedness
– Divergent features
• Ex. Number of toes in foot
Evolutionary biology is supported by:
•
•
•
•
•
•
•
•
Embryology
Paleontology
Crash course evolution
Biogeography
Anatomy
Physics
Botany
Biochemistry
Molecular biology
Grouping Species
• Taxonomy
– name and classify species into groups
Species Genus Family
Order
Class
Phylum Kingdom Domain
Ursus americanus
(American
black bear)
Ursus americana
Ursus
Ursus
Ursidae
Ursidae
Carnivora
Carnivora
Mammalia
Mammalia
Chordata
Chordata
Animalia
Animalia
Eukarya
Eukarya
September 15, 2009 Niger --Scientists excavate the 43-foot-long (13meter-long) skeleton of a new species of sauropod--or four-legged planteater. Spinophorosaurus nigerensis, had a tail studded with bony spikes that the
animal likely swung at predators
FYI
• Fossil whales (palenotology)
Homologous structures
Ex. Mammalian limb
• Charles Darwin On the Origin of Species by
Means of Natural Selection in 1859
• 2 main points:
1. Descent with modification
• Species share a common ancestor
100 mya Mesozoic ancestor to mammals
FYI: horse evolution
FYI: Extant (living)
horses
FYI: Evolutionary tree
Evolutionary tree shows ancestral
relationships Galapagos (Darwin’s) finches
Certhidea olivacea
Gray warbler finch
Certhidea fusca
Bud-eater
Seed-eater
Insect-eaters
Warbler
finches
COMMON
ANCESTOR
Green warbler finch
Sharp-beaked
ground finch
Geospiza difficilis
Vegetarian finch
Platyspiza crassirostris
Mangrove finch
Insect-eaters
Tree finches
Cactospiza heliobates
Woodpecker finch
Cactospiza pallida
Medium tree finch
Camarhynchus pauper
Large tree finch
Camarhynchus
psittacula
Small tree finch
Seed-eaters
Ground
finches
Cactusflower-eaters
Camarhynchus
parvulus
Large cactus
ground finch
Geospiza conirostris
Cactus ground finch
Geospiza scandens
Small ground finch
Geospiza fuliginosa
Medium ground finch
Geospiza fortis
Large ground finch
Geospiza magnirostris
• natural selection
– ancestral species  descendent species
– Ex. finch species of Galápagos Islands
2. Natural selection mechanism of evolution
Natural Selection
a. Traits vary randomly
b. More offspring produced than can survive
"In October 1838, that is, fifteen months after I had
begun my systematic inquiry, I happened to read for
amusement Malthus on Population, and being well
prepared to appreciate the struggle for existence which
everywhere goes on from long- continued observation
of the habits of animals and plants, it at once struck me
that under these circumstances favourable variations
would tend to be preserved, and unfavourable ones to be
destroyed. The results of this would be the formation of
a new species. Here, then I had at last got a theory by
which to work".
Elephants start to breed at around age 30. They
breed to 90 years old. In that time, one elephant has
6 offspring. Darwin calculated that after 750 years,
there would be 19 million desendants from the
original breeding pair IF all survived.
c. Competition for:
Mates
Food
Habitat
Water
d. Reproductive fitness is:
e. Traits are heritable
Number of offspring
Ability to attract mate
Health
Offspring survival
Avoiding predators
Avoiding parasites
• Because of natural selection, in time, more
individuals in a population will have
advantageous traits
• No acquired traits inherited!
• Natural selection results in adaptations
Ex. Bat wings
Examples of adaptations
Diversity of Life
• Evolution unifies biology
~1.8 million extant species have been identified
(could be >10 million)
FYI
6,300 bacteria
10,000 fungi
290,000 plants
52,000 vertebrates
1 million insects
New species 2012
Three Domains of Life
• Domain Bacteria and Domain Archaea
- Prokaryotic cells
• Domain Eukarya
– Eukaryotic cells
Anthrax
T. aquaticus
Paramecium
Methanobrevibacter smithii lives in the
human gut digests polysaccharides
Staphylothermus is found in
thrives on sulfur
98oC
hot spring,
Methanosarcinia rumen is anaerobic,
produces methane, is found in rumen of cows
Halococcus salfodinae lives in high salt
http://www.microbiologyonline.org.uk
Amoeba in motion
yeast
Eukarya includes
kingdoms:
(a) DOMAIN BACTERIA
Plantae
Fungi
Animalia
Protista
(b) DOMAIN ARCHAEA
(c) DOMAIN EUKARYA
Kingdom Plantae
Kingdom
Protista
Kingdom Fungi
Kingdom
Plantae
Kingdom Animalia
THE SCIENTIFIC METHOD
• Inquiry
– search for information and explanation
• 2 types of scientific inquiry:
– discovery
• Describe nature
– hypothesis-based
• Test hypothesis
Hypothesis - tentative answer to wellframed question, an educated guess
• leads to predictions that can be tested
Hypotheses
• must be testable
• test one hypothesis at a time
• Must be falsifiable
• does not need to be correct
More in lab
• Independent (experimental) variable
• the one aspect that varies among test groups
• Control group
– baseline group for comparison
• Controlled variables
– Held constant, do not vary among groups
• Dependent variable
– What is measured
EXAMPLE
• 2005, NJEM published results of study of Echinacea for
prevention and treatment of the common cold.
• The research team tested 3 preparations of the roots of a
Echinacea angustifolia. They extracted the root using
procedures that represent some of the different ways that
Echinacea is used to treat colds.
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Hypothesis:
Independent variable:
Control group:
What is a placebo?
What is a double blind study?
437 healthy adult volunteers were assigned at random to receive one
of the three root preparations or a placebo. The volunteers received
Echinacea or a placebo in two phases: a preventive phase and a
treatment phase. The preventive phase lasted 7 days. On the 7th day,
the volunteers were exposed to a nasal spray with a virus that induces
a cold in ~ 2 days. Then, volunteers were isolated for 5 days while
the research team observed and tested them as to the appearance and
severity of cold signs and symptoms.
Controlled variables:
Dependent variable(s):
100 nm = 0.0000001 meters
Scientific notation?
The researchers found that none of the 3 preparations of
Echinacea at the 900 mg per day dose had effects on
whether volunteers became infected with the cold virus
The 3 preparations did not affect the severity or duration
of symptoms among those who developed colds.
Critics of this study believe the dose of E. angustifolia used
was too low.
• Hypothesis
– Zinc helps people
recover from colds
Y axis??
Data
• Qualitative = descriptions
• Quantitative = measurements-organized into
tables and graphs
http://thesituationist.files.wordpress.com/2008/
02/jane-goodall.jpg
Quantitative:
Qualitative:
Limitations of Science
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Results must be repeatable
Science investigates natural world
Use natural processes in the explanation
Evidence based
Which hypothesis are testable/have evidence to
support?
Some plants eat meat.
Extraterrestrial beings have visited Earth.
Without light green plants will die.
Humanoid giants once lived on earth
Euthanasia is the right thing to do for terminally ill patients
Meditation can extend the length of life
Sunscreen prevents skin burning
Mermaids swim in the ocean
The flu virus mutates every year
Theories in Science
• Theory
– Broader in scope than hypothesis
– Can lead to new testable hypotheses
– Supported by large body of evidence
Theory of gravity
Theory of evolution
Theory of round earth
FYI: Summary of evidence supporting theory of
round earth
• When at sea it is possible to see mountains in the distance
• The sun is lower in the sky as you travel away from the tropics.
• The earth throws a circular shadow on the moon during a lunar
eclipse.
• It is possible to circumnavigate the world.
• An artifical satellite can circle the earth continuously
• The earth appears as a disc on photographs taken from space,
regardless of the vantage point.