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Unifying Themes in Unifying Themes in BiologyBiology
Evolution~ biology’s core theme; differential reproductive success
Emergent Properties~ hierarchy of life (new properties at each level)
The Cell~ all organism’s basic structure
Heritable Information~ DNA Structure & Function~ form and
function (Form determines function)
Environmental Interaction~ organisms are open systems
Regulation~ feedback mechanisms
Unity & Diversity~ universal genetic code
Scientific Inquiry~ observation; testing; repeatability
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1 µmOrganelles
Nucleus (contains DNA)
Cytoplasm
Membrane
DNA(no nucleus)
MembraneEukaryotic cell
Prokaryotic cell
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The biosphere
Communities
Populations
Organisms
Ecosystems
Organs and organ systems
Cells
Cell
Organelles
Atoms
Molecules
Tissues
10 µm
1 µm
50 µm
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Organs and organ systems
Cells
Cell
Organelles
Atoms
Molecules
Tissues
10 µm
1 µm
50 µm
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Hierarchy of OrganizationHierarchy of Organization
MoleculeOrganelleCellsTissuesOrganSystemsOrganism
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Macromolecules Macromolecules
Carbohydrates (CHO) - energyLipids (CHO) – long term energyProteins (CHON) – building &
workNucleic acids (CHONP) – genetic
information
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Feedback Regulation: Feedback Regulation: NegativeNegative
Accumulation of an end product of a process slows that process
Example: sugar breakdown generates ATP; excess ATP inhibits an enzyme near the beginning of the pathway
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Feedback Regulation: Feedback Regulation: PositivePositive
An end product speeds up its production
Example: blood clotting in response to injury
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The Process of ScienceThe Process of Science
Scientific MethodDeductive
reasoning“If….then” LogicHypothesis
(testable)Theory (widely
tested & accepted)Law (proven)
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Properties of Living Properties of Living ThingsThings
Paramecium Bacteriophage
Which is considered living? Why?
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Early Views of LifeEarly Views of Life
Vitalism: The insistence that there is some big, mysterious extra ingredient in all living things
Led to idea of spontaneous generation (life can come from nonliving material) Flies came from dead animals Mice came from Hay
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Idea was challenged by scientist Francesco Redi in 1698.
Designed an experiment where 3 jars contained meat.
The Redi ExperimentThe Redi Experiment
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Setup 1Setup 1
One Jar contained meat and had an open top which would allow the passage of flies. (maggots would appear on the
meat)copyright cmassengale 17
Setup 2Setup 2
The second jar was covered with an airtight lid not allowing the passage of flies. (no maggots would appear on the
meat) copyright cmassengale 18
Setup 3Setup 3
The third was covered by a screen allowing passage of eggs, but not flies. (few maggots would appear on
meat)
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ConclusionConclusion
Since the third setup would theoretically allow the passage of “ethers”, but no maggots appeared, it was implied that flies were the source of the maggots. (Deductive Reasoning) Led to the theory of Biogenesis
All life comes from preexisting life
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Order
Evolutionary adaptation
Responseto theenvironment
ReproductionGrowth
anddevelopment
Energyprocessing
Regulation
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PROPERTIES of LIFEPROPERTIES of LIFE
Be made of Cells.The Cell is the basic unit of life
Is self contained and possesses a barrier (membrane) which separates itself from the environment.
Two types of organisms. Unicellular - One celled organism (Uni=1) Multicellular - Many cells (Multi=”many”)
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CellsCells
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 is the basis of all reproduction, growth, and repair of multicellular organisms
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PROPERTIES of LIFEPROPERTIES of LIFE
Living Things must Reproduce.Must be able to create more of it’s own kindTwo types of reproduction:
Sexual - Two parent organisms combine genetic material to produce the offspring.
Asexual - When a single organism can divide or “bud” to create it’s offspring without another of it’s species.
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PROPERTIES of LIFEPROPERTIES of LIFE
Living things ALL Have DNA. Universal Genetic CodeInstructions for making all the
bodies proteinsLocated in the nucleus
(eukaryotes) or nucleiod region (prokaryotes)
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DNADNA
Chromosomes contain most of a cell’s genetic material in the form of DNA (deoxyribonucleic acid)
DNA is the substance of genesGenes are the units of inheritance that
transmit information from parents to offspring
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Each chromosome has one long DNA molecule with hundreds or thousands of genes
DNA is inherited by offspring from their parents
DNA controls the development and maintenance of organisms
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NucleicontainingDNA
Sperm cell
Egg cell
Fertilized eggwith DNA fromboth parents
Embryo’s cells withcopies of inherited DNA
Offspring with traitsinherited fromboth parents
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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 (A,T,C,G)
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Genes control protein production indirectly
DNA is transcribed into RNA then translated into a protein
An organism’s genome is its entire set of genetic instructions
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PROPERTIES of LIFEPROPERTIES of LIFELiving things must Grow & Develop.Growth refers to two processes.
Increase in the number of cells. Increase in the size of cells.
Development refers to changes in the organism which occur through it’s life-span. Includes cell differentiation. Includes organ development Includes aging & death.
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PROPERTIES of LIFEPROPERTIES of LIFE
Living things obtain & use energy.Energy is used by all living things for
growth, development & reproduction. Life processes which result in “building”
the organism ia known as Anabolism. (endergonic-store energy)
Life process where energy is extracted by “breaking-down” substances is called Catabolism. (exergonic-release energy)
ATP – cellular energy
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PROPERTIES of LIFEPROPERTIES of LIFE Living things must Respond (or react) to their
environment in some way. Something which causes an organism to react is
known as a Stimulus (stimuli). The ability of an organism to react is called
Irritability. Most responses are geared for maintaining
Homeostasis. Homeostasis is a process where an organism
maintains a stable internal environment so life can continue.
Some examples include temperature, pH, and water content of the cell.
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Organisms Interact with Their Organisms Interact with Their EnvironmentsEnvironments
Every organism interacts with its environment, including nonliving factors and other organisms
Both organisms and their environments are affected by the interactions between them For example, a tree takes up water and
minerals from the soil and carbon dioxide from the air; the tree releases oxygen to the air and roots help form soil
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Ecosystem DynamicsEcosystem Dynamics
The dynamics of an ecosystem include two major processes: Cycling of nutrients, in which materials
acquired by plants eventually return to the soil (Carbon, Phosphorus, Water, Nitrogen)
The flow of energy from sunlight to producers to consumers
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Sunlight
Ecosystem
Heat
Heat
Cyclingof
chemical
nutrients
Producers(plants and
other photosyntheti
corganisms)
Chemical energy
Consumers(such as animals)
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Evolution unifies biology at different
scales of size throughout the
history of life on Earth
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Diversity of LifeDiversity 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
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Grouping SpeciesGrouping Species
Taxonomy is the branch of biology that names and classifies species into groups of increasing breadth
Domains, followed by kingdoms, are the broadest units of classification
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Species
Genus
Family
Order Class Phylum
Kingdom
Domain
Ursus americanus(American black bear)
Ursus
Ursidae
Carnivora
Mammalia
Chordata
Animalia
Eukarya
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The Three Domains of LifeThe Three Domains of Life
The three-domain system is currently used, and replaces the old five-kingdom system
Domain Bacteria and domain Archaea comprise the prokaryotes
Domain Eukarya includes all eukaryotic organisms
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(a) DOMAIN BACTERIA
(b) DOMAIN ARCHAEA
(c) DOMAIN EUKARYA
Protists
Kingdom Fungi
KingdomPlantae
Kingdom Animalia 44copyright cmassengale
EukaryaEukarya
The domain Eukarya includes four kingdoms: Protista (unicellular) Fungi (mostly multicellular) Plantae (multicellular) Animalia (multicellular)
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Fossils and other evidence document the evolution of life
on Earth over billions of years
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Natural SelectionNatural Selection
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” Darwin’s theory explained the duality of
unity and diversity
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Darwin observed that: Individuals in a population have traits
that vary 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
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Darwin inferred that: Individuals that are best suited to their
environment are more likely to survive and reproduce
Over time, more individuals in a population will have the advantageous traits
In other words, the natural environment “selects” for beneficial traits
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Populationwith variedinherited traits.
Eliminationof individualswith certaintraits.
Reproductionof survivors.
Increasingfrequencyof traits that enhance survival and reproductive success.
4321
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Natural selection is often evident in adaptations of organisms to their way of life and environment
Bat wings are an example of adaptation
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The Tree of LifeThe Tree of Life
“Unity in diversity” arises from “descent with modification” For example, the forelimb of the bat,
human, horse and the whale flipper all share a common skeletal architecture
Fossils provide additional evidence of anatomical unity from descent with modification
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Darwin proposed that natural selection could cause an ancestral species to give rise to two or more descendent species For example, the finch species of the
Galápagos IslandsEvolutionary relationships are often
illustrated with tree-like diagrams that show ancestors and their descendents
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COMMONANCESTOR
Warb
ler
fin
ch
es
Insect-
eate
rs
Seed
-eate
r Bu
d-e
ate
r
Insect-
eate
rs
Tre
e fi
nch
es
Green warbler finch Certhidea olivaceaGray warbler finch Certhidea fuscaSharp-beakedground finch Geospiza difficilisVegetarian finch Platyspiza crassirostrisMangrove finch Cactospiza heliobatesWoodpecker finch Cactospiza pallidaMedium tree finch Camarhynchus pauperLarge tree finch Camarhynchus psittaculaSmall tree finch Camarhynchus parvulusLarge cactusground finchGeospiza conirostris
Cactus ground finchGeospiza scandens
Small ground finchGeospiza fuliginosaMedium ground finchGeospiza fortisLarge ground finchGeospiza magnirostris
Gro
un
d
fin
ch
es
Seed
-eate
rs
Cactu
s-
flow
er-
eate
rs
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