Download Biology 160

Biology 160
Sarah Redd
Course Expectations
What you should expect from this course:
Biol 160
is here
You’ll learn a lot, but it’s going to be a challenge.
How Colleges Calculate Credit Hours
• You should expect to spend 2-3 hours outside
of class for every hour you spend in class
• Biology 160 is 9 hours a week in summer
• If you want to do well, you should expect to
spend 18 - 27 hours per week outside of class
However…
http://blog.oregonlive.com/nwheadlines/2010/01
/todays_headlines_pictures_of_a.html
“Professor Toby Bradshaw begins to address his introductory biology
class at the University of Washington as a few stragglers in the class of
700 climb stairs to the balcony at Kane Hall. Budget cuts have forced
the biology department to offer fewer, but larger, classes.”
At RTC, you have the advantage of
personal attention. Use it!
•
•
•
•
Ask questions!
Get involved in class discussions!
Get to know your classmates!
Take charge of your education!
Why should you care about biology?
Biologists are answering interesting questions, like:
Why do we age?
Why should you care about biology?
Biologists are answering interesting questions, like:
Why does sex exist?
Why should you care about biology?
Biologists are answering interesting questions, like:
Why do we cooperate?
Why should you care about biology?
Your biology knowledge could land you a great job!
12/30=40%!
Overview: Inquiring About the World
of Life
• Biology is the scientific study of life
• How do we define life?
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 1-3b
Evolutionary
adaptation
Fig. 1-3c
Response
to the
environment
Fig. 1-3d
Reproduction
Fig. 1-3e
Growth and development
Fig. 1-3f
Energy processing
Fig. 1-3g
Regulation
Fig. 1-3a
Order
Fig. 1-4
The importance of scale: levels in the biological hierarchy
The biosphere
Cells
Organs and
organ systems
10 µm
Cell
Ecosystems
Organelles
Communities
1 µm
Atoms
Tissues
50 µm
Molecules
Populations
Organisms
Fig. 1-4l
Atoms
Molecules
Fig. 1-4k
1 µm
Organelles
Fig. 1-4j
10 µm
Cell
Cells
Fig. 1-4i
Tissues
50 µm
Fig. 1-4h
Organs and
organ systems
Fig. 1-4g
Organisms
Fig. 1-4f
Populations
Fig. 1-4e
Communities
Fig. 1-4d
Ecosystems
Fig. 1-4c
The biosphere
Organizing the Diversity of Life
• Approximately 1.8 million species have been
identified and named to date, and thousands
more are identified each year
• Estimates of the total number of species that
actually exist range from 10 million to over 100
million!
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 1-15
(a) DOMAIN BACTERIA
(b) DOMAIN ARCHAEA
(c) DOMAIN EUKARYA
Protists
Kingdom
Plantae
Kingdom Fungi
Kingdom Animalia
Carolus Linnaeus
•Swedish botanist who
devised our
classification system
(1707-1778)
Image from: http://www.medusozoa.com/images/linnaeus.jpg
Linnaeus’s System
•Organisms within a domain are
grouped in a hierarchy of 7 different
taxonomic levels,
or taxa
•
•Each organism has a two part
scientific name
•= Genus species
Fig. 1-14
Species Genus Family Order
Class Phylum Kingdom Domain
Ursus americanus
(American black bear)
Ursus
Ursidae
Carnivora
Mammalia
Chordata
Animalia
Eukarya
Kingdom
Kids
Phylum
Prefer
Cheese
Class
Over
Order
Fried
Family
Green
Genus Spinach
Species
Kingdom Animalia
Phylum Chordata
Class Mammalia
Order Carnivora
Family Felidae
Genus Panthera
Species leo
http://www.vetmed.wisc.edu/dms/fapm/personnel/tom_b/2004-lion.jpg
BINOMIAL NOMENCLATURE
(2-name naming system)
•1st name = Genus
– Always capitalized
2nd name = species
–Always lower case
Both names are italicized or underlined
GENUS = group of closely related species
•GENUS = Ursus
(Includes many kinds of bears)
Ursus
arctos
Ursus
maritimus
Ursus
americanis
SPECIES = unique to each kind of bear
http://www.macecanada.com/images/bears/kodiak_bear.gif
http://students.cs.byu.edu/~tole/Virtual%20Zoo/polar-bear.jpg
http://en.wikipedia.org/wiki/Image:Black_bear_large.jpg
Binomial nomenclature
•Humans
Homo sapiens
Homo sapiens
Image from: http://www.earlylearning.ubc.ca/images/photo_baby.jpg
Why do we need scientific names?
Common names can vary…
Example:
puma,
catamount,
mountain lion,
cougar
. . . are all names
for same animal
Image from: http://www4.d25.k12.id.us/ihil/images/Cougar.jpg
By using a universally accepted scientific
name, scientists can be sure they are
discussing the same organism.
Themes connect the concepts of biology
• Biology consists of more than memorizing factual details
• Themes help to organize biological information
• Thinking about the themes that organize all the little pieces of
information can make it easier to remember detailed concepts
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Theme: Structure and function are
correlated at all levels of biological
organization
• Structure and function of living organisms are
closely related
– A leaf in an area that gets enough water is thin and flat,
maximizing the capture of light by chloroplasts
– Leaves in dry, windy areas have thick leaves that are not
quite as good at capturing light, but minimize water loss
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 1-6
(a) Wings
(b) Bones
Infoldings of
membrane
Mitochondrion
100 µm
(c) Neurons
0.5 µm
(d) Mitochondria
Theme: Cells are an organism’s basic
units of structure and function
• The cell is the lowest level of organization that
can perform all activities required for life
• All cells:
– Are enclosed by a membrane
– Use DNA as their genetic information
• The ability of cells to divide and make new cells
is the basis of all reproduction, growth, and
repair in multicellular organisms
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
2 Major Categories of Cells
• A eukaryotic cell has membrane-enclosed
organelles, the largest of which is usually the
nucleus
• By comparison, a prokaryotic cell is simpler and
usually smaller, and does not contain a nucleus
or other membrane-enclosed organelles
• Bacteria and Archaea are prokaryotic; plants,
animals, fungi, and all other forms of life are
eukaryotic
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 1-8
Eukaryotic cell
(animals, plants, fungi, protists)
Membrane
DNA
(no nucleus)
Membrane
Prokaryotic cell
(bacteria and
archaea)
Organelles
Nucleus (contains DNA)
1 µm
The Core Theme: Evolution accounts for
the unity and diversity of life
• “Nothing in biology makes sense except in the
light of evolution”—Theodosius Dobzhansky
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Evolution, the Overarching Theme of
Biology
• Evolution = Change over time
• Evolution makes sense of all the different
characteristics and interactions we observe in living
organisms
• Organisms living on Earth are modified descendents of
common ancestors
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
• Charles Darwin was a
medical student in
England, but he thought
lectures were boring and
surgery was disturbing
• Darwin landed a job as a
naturalist on the ship The
Beagle, exploring parts of
South America, Africa, and
many islands
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Charles Darwin and the Theory of
Natural Selection
• Darwin noticed many fossils that looked similar to
animals that were currently living, but with some
differences
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
• Charles Darwin published
On the Origin of Species by
Means of Natural Selection
in 1859
• Darwin made two main
points:
– Species showed evidence of
“descent with modification”
from common ancestors
– Natural selection is the
mechanism behind “descent
with modification”
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 1-19
• Darwin observed that:
– Individuals in a population have traits that vary (they’re not
all exactly the same)
– Many of these traits are heritable (passed from parents to
offspring)
– More offspring are produced than survive
– Competition is inevitable
– Species generally suit their environment
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
• Darwin inferred that:
– Individuals that are best suited to their environment
are more likely to survive and reproduce
– If they pass their beneficial traits on to their
offspring, over time more individuals in a population
will have the advantageous traits
• In other words, the natural environment
“selects” for traits that are beneficial in that
environment.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 1-20
1
Population
with varied
inherited
traits.
2
Elimination
of individuals
with certain
traits.
3
Reproduction
of survivors.
4
Increasing
frequency
of traits that
enhance
survival and
reproductive
success.
What happens if your environment
changes?
• Different traits are advantageous in different
environments.
• Dark beetles might leave more offspring if
they blend in with their environment
• In a lighter colored environment, lighter
colored beetles will probably leave more
offspring
“Survival of the Fittest”
• Fitness is a measure of how well you are
adapted to your environment and are able to
pass on your genes (reproduce)
• Being big and tough is not always more fit
• When scientists measure fitness, they usually
measure how much an organism reproduces
and how many of its offspring survive
Recap: Requirements for Natural
Selection
1. Variation between individuals
2. At least some of that variation is heritable
(passed on from parents to offspring)
3. Differential survival and reproduction (which
version of the trait you have affects how well
you survive and reproduce)
From http://www.nps.gov/whsa/naturescience/upload/Rosenblum%20-%20lizards.pdf
Speciation
• Due to different environments, some beetle
populations could evolve to be darker while
other populations could evolve to be lighter
• Eventually, the different populations of
beetles might become so different that light
beetles and dark beetles never mated and had
offspring together.
• Then they would be two separate species!
Linking Classification and Phylogeny
• Systematists depict evolutionary relationships in
branching phylogenetic trees
Over a long enough period of time, evolution can lead
to lots of new species
Fig. 26-4
Order
Family Genus
Species
Taxidea
Taxidea
taxus
Lutra
Mustelidae
Panthera
Felidae
Carnivora
Panthera
pardus
Lutra lutra
Canis
Canidae
Canis
latrans
Canis
lupus
Fig. 26-2
It is incorrect to say that humans
evolved from chimpanzees, or that
chimpanzees evolved from gorillas
• Homo = Genus of humans
• Pan = Genus of chimpanzees and bonobos
• There have been substantial interchanges of genes
between organisms in different domains.
• Horizontal gene transfer is the movement of genes
between organisms that doesn’t involve
reproduction.
• Horizontal gene transfer complicates efforts to
build a tree of life
Fig. 26-22
Bacteria
Eukarya
Archaea
4
3
2
Billions of years ago
1
0
Horizontal Gene Transfer can speed up
the rate at which species change
• Elysia chloratica (picture by Nicholas E. Curtis and Ray Martinez)
• http://biology.umaine.edu/symbio/3Slug/3about.html