Post on 17-Feb-2018
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Biology - study of life
All living things:
1. sense and respond to environment
2. capture and use energy
Metabolism = all the chemical reactions in a cell
Homeostasis = maintain internal operating conditions
within a range
3. reproduce, develop, grow
New cells only arise from previous cells
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4. are composed of at least one cell Some unicellular
Some multicellular
5. contain DNA Genes provide the instructions for the cell
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Genus and species
Binomial nomenclature
every living organism has two names which represent the genus and species
Felis domesticus F. domesticus
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Life’s diversity
•2 million species have been described
•Half are…..
•could be over 15 million species
•Living things are classified = Taxonomy
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No nucleus in cell Presence of nucleus in cell
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Eukarya Kingdom Animalia motile, multicellular,
consumers
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Fig 19.6 Sponges are most primitive,
vertebrates are most advanced animals
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Example of an animal useful to humans
Diabetes drug from venom/saliva
Gila monster (lizard)
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Kingdom Plantae (400 million years)
370 feet
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Plants – characteristics?
Multicellular
Most are flowering
Photosynthesis
light
CO2 + H20 ------> O2 + starchSunlight is ultimate energy source for life – why?
Plants are producers
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Example of a plant useful to humans: Aloe
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Kingdom Fungi = molds, fungus, yeast
•Secrete chemicals to break down and
absorb food from dead or living matter
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2 important fungal medicines:
Cyclosporin (1971) Tolypocladium inflatum
Suppresses immune system… so…..
Used in organ transplants, psoriasis,
rheumatoid arthritis
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Penicillin antibiotic
From bread mold
Revolutionized medicine
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PRODUCERS
CONSUMERS
DECOMPOSERS
Fig. 1.4
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Kingdom Protista also called protozoa
Includes algae and
seaweed!
And some unicellular
organisms
Algae, Paramecium, amoeba
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A useful protozoan
red algae (Chondrus crispus
Contains carageenen)
Thickener
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Domain Bacteria
3.5 billion years old
Prokaryotic cells
No nucleus
Single-celledintestine
plant
roots
On octopus mouth
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Domain Archaea
Methanosarcina mazei makes
methane from acetate
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Extremophiles
Have been found in thermal vents, salt crystals, ice,
acid environments
Extraterrestrial life?
I
MARSGeyser (hot!)
“Chance favors the prepared mind” Louis Pasteur
SCIENCE Science - a process of discovery
objective
explain world using natural
processes
fish dead
because there
was a curse on it
fish dead
because there’s
no food in its
tank
Why is the fish dead?
Scientific method
I. OBSERVATION
2. HYPOTHESIS
educated guess
comes before the experiment
must be testable and falsifiable
Hypothesis must be Testable
• Zinc lozenges ward off the common cold
• Colds are disturbances in psychic energy
• Meditation improves the immune system
– Hypothesis must be falsifiable
– Eggs lead to heart disease
– The earth is round
Hypothesis – educated guess
Theory – supported by all data, a unifying
concept
Theory of gravity
Round earth
Mars year = 687 earth days Mercury = 87.8 earth days
The Scientific Method1. Observation
2. Hypothesis
3. Experimental Design
1. Experimental (independent) variable
2. Controlled variables
3. Control group = often a “no treatment” group
4. Measurement (dependent variable)
Never ignore data and stay away from
preconceived ideas
minimize bias
1. Double blind studies
Randomized
Controlled
2. Placebo
Placebo effect
The placebo effect = observable or felt
improvement in health not attributable to
treatment.
In a double-blind, placebo-controlled study of 30 people
with carpal tunnel syndrome, use of a static magnet
produced dramatic and enduring benefits, but so did use
of fake magnetsCarter R,. J Fam Pract. 2002;51:38–40.
When participants in a trial of a new drug for reducing
cholesterol are given a placebo their cholesterol
levels are likely to fall significantly. Why?
A double blind randomized study prevents bias.
Reading graphs
A double blind, randomized
experiment was conducted.
100 people drank echinacea tea
every day for 4 months of winter.
100 people drank tea made with a
placebo. All subjects got colds.
The subjects were assessed for
severity of cold symptoms.
Evolution
Change through time
Change over time
“all organisms present of Earth today are
descendents of a single common ancestor
and all organisms represent the product of
millions of years of evolution”
Also known as common descent
Species
Group that can interbreed
Microevolution
Change within a species or population over
time
Speciation
New species arise from ancestral species
What is a Species?
One species is reproductively isolated from other
species.
Shares gene pool
HobbsMale lion female
tiger male ligers are
sterile, female ligers
are fertile
All humans share a common ancestor
Horses have undergone much speciation
Sharks have changed very little in 40
million years
Megalodon, a 50 ft shark that
lived ~20 million years ago
Natural Selection
How do we know what happened a long
time ago (geological time)?
250 mya Pangaea – continents came together
dramatic environmental change
mass extinction
Fig 16.13
Geological Time Scale
Age of Earth:
When living organisms first appeared:
Humans have been on Earth for 0.04% of the history of life
Natural selection
Natural Selection and common
descent (1859)
Charles Darwin T.H.
Huxley
HMS Beagle
Galapagos Islands
Volcanic islands off coast of Ecuador contain unique
species of plants and animals
Tortoise marine iguana
1836
Video
iguana
ala
Adaptive radiation
FINCHES HAVE ADAPTED TO ENVIRONMENTS
Fig. 14.6
Diet of seeds
Beak to catch insects
Probes cacti for nectar
All descended from a single ancestral species
Natural Selection – how does it
work?
1. Random variationA. All populations of organisms vary randomly
Variations are NOT imperfections but a normal aspect of
species
B. Variation occurs due to mutation and
sexual reproduction
mutation = heritable change in DNA
DNA also rearranges during formation of sperm
and egg
C. Variation inherited from parent to offspring
What is a mutation?
Most are neutral mutations : no effect on fitness
“Mutant” melanin gene normal melanin gene
Blond phenotype brown phenotype
A few are harmful mutations :
hemophilia
A few are positive mutations :
beneficial (longer neck in giraffe)
2. Not all offspring survive
Examples: 1 sea star has 4 million offspring – which survive?
3. “Survival of the fittest”=
The most “fit” organisms survive andpass their genes on
Fitness is determined by the environment
Fitness = reproductive success
THIS IS NATURAL
SELECTION
Another adaptation to
avoid predation
Fig 14.9
Brazilian alligator bug
The most fit organisms survive to reproduce
Traits that increase fitness are adaptations
Examples of adaptations (increase
fitness)
Offspring inherit traits of parents =
4. Descent with modification =
Evolution
Natural selection results in adaptive traits
increasingly represented in each
succeeding generation
May take a lot of time for change to be
obvious and/or lead to a new species
Speciation
Ancestral species give rise to new species
Artificial Selection – breeding of domesticated
animals and plants by humans, this is NOT natural
selection Cows, corn, dogs
Bulldog HHMI video
1. GeologyEarth does change
Not all due to catastrophy
Shaped by gradual, natural, slow processes
erosion, wind, rain
How old is the earth?
The Grand Canyon was not
produced by a catastrophe
Arizona
2. Fossils History of life recorded by remains of past
Buried in volcanic ash or sediments for >10,000 years
Types
Impression
Bones, teeth
Amber
Petrified wood
Mosasaurus
Tooth 50 ft. 70 mya
Why is the fossil record
incomplete?
75% of the earth is ocean
Many destroyed by weather
Fossils don’t always form A small number are buried in the right way (fast) to prevent decomposition
Cant dig up entire earth
No soft parts
Only the hard parts remain after fossilization process
99% of species once alive are extinct
Stratification: simple=oldest= deepest
Succession of life
forms
Hadrosaurus, Haddonfield, NJ 1858
The NJ State Dinosaur
Coelacanths!
1938, a Coelacanth was caught at the mouth of the Chalumna River on the east coast of South Africa.
70 million year old fossil
Fossils found a few years ago
A bison-size rodent, Phoberomys pattersoni, grazed
on aquatic grasses and roamed the riverbanks of ancient
Venezuela about 8 million years ago.
Glyptodon and modern
armadillo
Ancient whales
Kutchicetus 40 mya
A famous hominid fossil
1974, Hadar, Ethiopia.
Lucy – (Australopithecus afarensis)
East Africa ... 3.2 million years ago
300 individuals found 3 feet 8 inches tall More ape-like than human
1. Australopithecus
afarensis
2. Australopithecus
africanus
3. Homo habilis 4. Homo erectus
5. Neandertal
archaeopteryx- a
dinosaur/bird link
Late Jurassic period, and specimens have been found in limestone deposits in Bavaria, West Germany. The first specimen was discovered in 1861, and since then six skeletons have been found.
3. transitional forms
monitor lizard “Komodo dragon”
500 lbs 10 feet
Indonesia Varanus komodoensis
4. Biogeography
•Animals on each
continent related
•Islands species related
to species on mainland
5. Anatomy
Homologous
structures
Share a common
evolutionary history but
may be used for
different functions
Fig. 14.14
Analogous structures
similar function but no shared evolutionary
history
Vestigial structures
Function lost during
evolution, no longer
needed
human appendix, whale leg
bones, snake leg bones
6. Embryology
vertebrate body
plan for
development
= shared descent
DNA evidence of relatedness of
species
Humans share 99.9% of DNA
Human DNA is 99.01 % similar to
chimp
90% with mice
Pre- and post-evolutionary theory,
page
Mammals- what makes a mammal a mammal?
Ex. Duckbilled platypus
Monotremes are the most
primitive mammals
Ornithorhynchus anatinus
Marsupials – development in
pouch
Placental mammals
Born more fully developed
Placenta in uterus
Ex. Bat, polar bear, human, whale, cow,
armadillo……..
Review
Your notes are important – rewrite them or
type, study them and refer to textbook
This review is not comprehensive
Good luck on exam 1.
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DOMAIN Archaea? Bacteria? Eukarya?
Prokaryotic
Protista
Live in extreme environments
Penicillin
Photosynthesize
Eukaryotic
Includes worms and beetles
Onion
E. coli
KINGDOM Animalia Plantae Fungi Protista
Cyclosporin
Producers
Aloe
Use sun as energy
Some are single celled
Poisonous dart frog
Consumers
Coelecanth
Mold
Producers
Yeast used to make bread and beer
Photosynthesis
Motile and multicellular
Absorb living or dead matter
Duckbilled platypus
Microscopic
Lucy
Homo sapiens
Animals
What are
Mammals Animals
Homo sapiens Plants
Genus Homo Sponge
Sharks Hybrid
Vertebrates Platypus
Kangaroo Fungi
Snakes Hadrosauras
Archeopteryx Lucy
Common descent (yes or no)?
All living things share a common ancestor
All life was created a few thousand years ago
All species that have ever lived were created at
the same time
Species have given rise to new species over time
All species of living things lived during the same
time period but some have died out
Life is about 3.6 billion years old
The first living things on earth were single-celled
bacteria
The Earth is about 4.7 billion years old
Homologous ?
Bird wing and bat wing
Dolphin flipper and bat wing
Snake tail and human coccyx
Appendix and coccyx
Penguin flipper and shark fin
Human arm and chimp armWhich are vestigial?
Fossil (extinct) or alive today? Dinosaur Hadrosauras
500 pound rodent Archaeopteryx
Eukaryotes Archaea
Coelacanths Whales with legs
Neanderthal man Descendants of dinosaurs?
Homo sapiens Archaea
Homo erectus Whales with internal leg bones
Mammals that lay eggs
Protists
Megalodon (giant shark)
Komodo dragon (monitor lizard)
Which is a transitional form?
How do these disciplines provide evidence
for species changing over geological time?
Anatomy – homologous and vestigial structures
Geology – catastrophies and slow changes
Embryology and a vertebrate body plan
Biogeography and relatedness of species
Paleontology and the discovery of fossils and
transitional fossils
DNA science and comparison of DNA of species
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concepts
Metabolism Hypothesis and theory
Homeostasis Double blind study
Life Biology
Photosynthesis Placebo
The scientific method
Erosion
Speciation
Evolution by natural selection
Common descent
Microevolution
Embryology
Species
The scientific method
Scientists studied 400 people who have psoriasis. All have suffered from this skin condition for at least 10 years. One group of people are given the immunosupressant, cyclosporin, every day for one month. The other group took a placebo. After one month, the effects of the drug on psoriasis was measured.
1. What is the hypothesis?
2. What is the experimental variable?
3. What is the control group?
4. How would you make this a double blind experiment?
5. What are 3 controlled variables?
6. What is measured?
Why does the control group take a pill at all?
When making the two groups, why not put all the severe sufferers in
the + drug group and the less severe ones in the control group?
Interpret the graph