BIO final

What defines something as alive?

1. The ability to assimilate and use energy
2. The ability to respond to their environment
3. The ability to maintain a relatively constant internal environment
      (homeostasis)
4. Having evolved from other living things
5. The ability to reproduce
6. Being composed of one or more cells with information encoded by DNA
7. Being highly organized when compared to inanimate objects
8. The ability to grow and develop

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Non-living objects are not self-sustaining I:Inanimate

Steps of the scientific method: [ Observation = What’s happening?  Questions = What do we want to know?  Formulate Hypothesis = Our proposed explanation for the unknown phenomena.  Must be testable  Must be falsifiable (have the potential to be proven false)  Methods/ Experimentation = Testing our hypothesis  Results = What did we discover?  Conclusion = Does it support or refute our hypothesis?]()

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Atoms are made up of three subatomic particles:

Protons: component of the atom’s nucleus with a positive electrical charge. Elements are defined by number of protons.

Neutrons: component of the atom’s nucleus with no electrical charge.

Isotopes are defined by number of neutrons.

Electrons: located some distance from atomic nucleus and has a negative electrical charge.

Atoms bond together to stabilize outer (valence) shell electrons.

Types of Chemical Bonding
Hydrogen bonding: a special type of
covalent bond between positively
charged hydrogen atoms and
negatively charged atoms in
separate molecules

Bound by attraction of electrical charges

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Hydrogen bonds between water molecules give water many of its unique properties

Bond between electronegative oxygen and electropositive hydrogen atoms in separate water molecules.

Properties of Water The Universal Solvent

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Water can dissolve more substances than any other liquid (the hydrogen bonds between water molecules pull other compounds apart)

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Solute: substance being dissolved to form a solution; typically a solid.

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Solvent: substance that a solute is dissolved in to form a solution; typically a liquid. Solution: a homogeneous (equal) mixture of two or more substances.

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Properties of Water
Water is a polar molecule
Partial

 Polarity works to pull apart ions
negative
charge
Partial
positive
charge

Liquid form is denser than solid
form
 Ice floats on water!

Properties of Water
Cohesion: the tendency for like
molecules to cling
together due to attractive
forces (like hydrogen
bonds)

Surface tension: water molecules are not attracted to air and
pack more tightly at interface between air and water.

Specific heat: amount of energy required to raise temp 1˚C
 Water has a high specific heat compared to other molecules
 Water acts as buffer to temperature changes

High heat of vaporization

 Vaporization: transformation from liquid to gas
 Fastest moving water molecules transform to a
gaseous state.

Macromolecules: large organic molecule, usually comprising
smaller molecules (monomers) joined together to form a polymer

 Monomers: a smaller molecule that can be combined with other similar or
identical molecules to create a polymer

 Polymers: a larger molecule made up of many similar or identical subunits
Four major macromolecules

 Carbohydrates
 Lipids
 Proteins
 Nucleic Acids

Monomers and Polymers
Examples from common macromolecules

Carbohydrates
 Essential to energy production
 Simple carbohydrates (monomers)
 Monosaccharides and Disaccharides
 Glucose and sucrose
 Complex carbohydrates (polymers)
 Polysaccharides
 Cellulose (indigestible plant fiber), starch,
glycogen

Lipids
Fatty acid: long hydrocarbon found in many lipids
Triglyceride: lipid molecule formed by three fatty acids bonded to a
glycerol
 Most common lipid molecule found in foods

• 3H2O
    Glycerol + 3 fatty acids = triglyceride + water

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Nucleic acids are large molecules made up of nucleotides  Nucleotides: Organic molecules that serve as the building blocks (monomers) of nucleic acids, and are made up of a phosphate group, a sugar, and a nitrogenous base  DNA and RNA  Instructions for making proteins  ATP  Energy transfer

 Proteins: a long, folded polypeptide
 Polypeptide = a chain of amino acids
 Amino acid = compounds consisting of an amino and
carboxyl functional group, which act as the building blocks
(monomers) of proteins.

The Small Intestine
 6m long!
 Smaller diameter than large
intestine
 80% of nutrients absorbed
 Receives secretions from
digestive glands
 Liver
 Pancreas
 Gallbladder

Domains of Life
 Bacteria
 Unicellular prokaryotes
 Archaea

 Extremophiles
 Eukarya
 Unicellular and
multicellular eukaryotes
 Protists
 Fungi
 Plants
 Animals

Prokaryotic and Eukaryotic Cells
Eukaryotic
cell
Prokaryotic
cell

Domain: Bacteria
 Prokaryotic cells
 No membrane bound nucleus or
organelles
 Circular DNA
 Have a plasma membrane and a
cell wall
 Single-celled organisms.
 Asexual reproduction.

Prokaryotic Cells
Pili: attachment structures on the
surface of some prokaryotes.

Nucleoid region:
location of cell’s DNA (not
enclosed in a nucleus).

Ribosomes: site
of protein
synthesis.

Cell wall: rigid
structure outside of
Bacterial
cell membrane.
chromosome
(DNA)

Glycocalyx: sticky outer
coating on many
A typical A thin section through the
rod-shaped prokaryotes. bacterium Bacillus coagulans
bacterium

Flagella: locomotion
organelles in some
bacteria.

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Domain: Eukarya
 Eukaryotic cells
 Larger in size
 Have nucleus and other
membrane bound organelles
 Linear DNA
 All have plasma membranes,
but only plant cells have cell
walls
 Unicellular and multicellular
organisms.
 Sexual and asexual
reproduction.

Cell Theory
 All living organisms are
composed of cells.
 Cells come from pre-existing
cells

Plant and Animal Cells

Protein Production Summary

Protein Production: Step 1
Transcription: process in which a section of DNA is copied onto
messenger RNA (mRNA) in the nucleus.
RNA polymerase
mRNA
DNA
Direction of transcription

Protein Production: Step 2
Translation: process by which a polypeptide is produced in a
ribosome from information encoded within a messenger RNA
(mRNA)

Movement of Molecules
Diffusion: passive
movement of molecules
from a region of high
concentration to a region
of low concentration;
requires no energy input.

Movement Through the Plasma Membrane

Movement Through the Plasma Membrane
Passive transport: movement of ions or molecules across the
plasma membrane without the use of energy
 Simple diffusion: movement of ions or molecules directly through the cell
membrane without the use of a protein channel (transport protein)
 Facilitated diffusion: movement of ions or molecules across the plasma
membrane through a specialized protein channel (transport protein).
Active transport: movement of ions or molecules across the plasma
membrane against the concentration gradient with the use of energy
(ATP)

Membrane Permeability

Functions of Membrane Proteins

Functions of Membrane Proteins
Communication proteins:
Membrane proteins that bind
with signaling molecules on
exterior of cell and initiate a
response in the cell interior.
 Binding sites specific to certain
signaling molecules.
 Adrenaline and beta blockers

Cellular Respiration
Three-part process that converts a
single glucose molecule into
energy/ATP.

1. Glycolysis
       2 ATP (actually 4, but 2 are used)
2. Krebs cycle
       2 ATP
      3. Electron transport chain
       32 ATP

Glycolysis
 Breakdown of 1 glucose molecule into 2 pyruvate molecules.
 ONLY step of cellular respiration to occur in cytoplasm/cytosol
outside of mitochondria
 Two stages:
 Energy investment stage: requires 2 ATP.
 Energy harvesting stage (from glucose’s electrons): produces 4 ATP and 2 NADH.
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Anaerobic Pathway
Fermentation: metabolic pathway that regenerates NAD+ from
NADH and allows for glycolysis to continue making ATP in the
absence of oxygen.
 Alcohol fermentation:
 Yeast in anaerobic environment.
 Lactic acid fermentation:
 Occurs in muscles when ATP use exceeds oxygen intak

Alcohol Fermentation
 Ethanol (drinking alcohol) is produced when acetaldehyde (pyruvate
derivative) accepts electrons from NADH following glycolysis.
 The resulting NAD+ then goes back to restart glycolysis

Thermoregulation and Thermodynamics
Thermoregulation: Process by which animals maintain their body
temperature within a normal range
 Endothermic: body temperature maintained by metabolic heat
 Birds, mammals, and some insects
 Ectothermic: body temperature controlled by external sources
 Most reptile, fish, and invertebrates
 First Law of Thermodynamics: energy cannot be created or
destroyed, only transferred
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Heat Exchange with Environment
 Conduction - direct transfer of heat
 Convection - transfer of heat by the
movement of air or water across a
surface
 Radiation - emission of
electromagnetic waves
 Evaporation - loss of heat from
changing a liquid into a gas
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Adaptations for Thermoregulation - Energy Conservation
 Torpor: physiological state of
decreased activity and
metabolism.
 Hibernation: long term torpor and a
decreased body temperature in
response to winter cold and food
scarcity
 Estivation: short or long term torpor
in response to summer heat and
water scarcity

Cellular Respiration and Photosynthesis
Cellular Respiration: aerobic harvesting of energy
 Aerobic = requires oxygen
Photosynthesis: conversion of solar energy to chemical energy
Photosynthesis
Light energy
6H2 + 6CO2 C6H12O6 + 6O2
Carbon Glucose Oxygen
O
dioxide
Water
Cellular Respiration
C6H12O6 6O2 6H2 6CO2 36AT Heat

• \
    * \
      * +
        Glucose Oxygen Carbon
        O P
        dioxide
        Water

Site of Photosynthesis
Stomata: pores on leaf where gas exchange
occurs
Chloroplasts: organelles in plants and algae
where photosynthesis occurs
Thylakoids: membranes within the
chloroplasts
 Location of photosynthetic pigments and
light reactions of photosynthesis
Stroma: liquid, gel-like substance inside
chloroplasts that thylakoids are suspended in
 Location of dark reactions of photosynthesis
(Calvin cycle)

Two Stages of Photosynthesis

1. Light Reactions: electrons from
      water are excited by solar energy
      and used to power the formation
      of ATP and NADPH (electron
      carrier)
       Takes place in thylakoid membrane
       Oxygen byproduct
2. Calvin Cycle: energy from light
      reactions (ATP and NADPH) used
      to convert CO2 to carbohydrates
      by stripping carbon from CO2
       Takes place in stroma

Photosynthetic Pigments
Pigments: molecules that absorb and
reflect certain wavelengths of light.
 Primary photosynthetic pigments:
responsible for majority of photosynthesis in
plants
 Chlorophylls a and b absorb red-orange and blue-
violet wavelengths.
 Secondary photosynthetic pigments: fill
in the gaps where/when primary pigments
cannot photosynthesize
 Carotenoids absorb blue-violet and green
wavelengths.
 Which wavelengths do they reflect?

Stomata
Stomata open Stomata closed

Evolutionary History of Plants
Phylogenetic tree: diagram
showing evolutionary
relationships among organisms
 Groups organized by their
Flowers
shared characteristics
 Common ancestor
Seeds
Vascular tissue

Nonvascular Seedless Plants
 Mosses, Liverworts, Hornworts
 Lack vascular tissue
 Transport by diffusion
 Limited vertical growth
 Rhizoids
Mosses
 Precursors to true roots; very short
Liverworts
 Reproduce asexually via spores (a packet of
plant cells capable of growing into a new plant
ONLY in a moist environment)
 Reproduce sexually via gametes (sperm and
eggs)
Hornworts
 Flagellated sperm require wet environments to
be able to swim to and fertilize an egg.

Evolution of Seeds
Seed: a plant embryo and its
food supply inside a protective
layer (seed coat); much more
successful than spores.
 Seed coat offers seed a longer
lifespan
 Allows for dormancy until environmental
conditions are perfect
 Cotyledons: seed leaves; first
leaves to emerge and begin
photosynthesis
 Endosperm: energy rich tissue that
nourishes developing embryo; food
supply (starch).

Asexual Reproduction in Vascular Seed
Plants
 Vegetative propagation: a
method of asexual reproduction
in plants, where a root, stem, or
leaf is used to grow a new
plant.
 Resulting plants are clones of
original plant (no new genetic
information is introduced)

Adaptations to Reduce Transpiration
 Small, thick leaves
 Hairy/light-colored leaves
(reflect sunlight)
 Thick, waxy cuticle (non-polar
leaf coating repels water)
 Sheltered/hairy stomata
 Drop their leaves in a drought
Ocotillo, a Sonoran
 C4 and CAM photosynthesis Desert staple, has nearly
all of these adaptations.

Meiosis vs. Mitosis
Mitosis Meiosis
 Produces 2 identical
 Produces 4 non-identical
daughter cells
daughter cells
 Daughter cells 2n (diploid)
 Daughter cells n (haploid)
 One cell division
 Two cell divisions (Meiosis I and
 Occurs in somatic cells for II)
growth/development, and to
 Occurs in production of egg and
replace damaged or dead
sperm cells (gametes)
cells
 Increases genetic diversity via
 Does not increase genetic
crossing over and independent
diversity
assortment

Sources of Genetic Variation
Crossing over = process in which homologous chromosomes exchange
reciprocal portions of themselves during
Prophase I of meiosis

Comparison of Chromosome Number
Haploid: cells with a single
copy of each chromosome
 Gametes: sex cells
 Egg and sperm
 Produced via meiosis
Diploid: cells with two
copies of each
chromosome, one maternal
and one paternal
 Somatic cells: cells forming
the body of the organism
 Produced via mitosis

Males and Females
Individuals have two copies of
sex chromosomes in every
cell.
 Females = Two X chromosomes.
 Males = One X and one Y
chromosome.
Each egg gets Half the sperm cells get
an X chromosome, and
one X
half get a Y chromosome.
chromosome.

Differences between DNA and RNA
RNA is single stranded and DNA is double stranded (double
contains uracil instead of helix) and contains thymine instead
thymine of uracil

DNA Replication
Helicase: enzyme that unwinds
DNA separating it into two
complementary strands.
DNA Polymerase: enzyme that
creates the complementary strand
by adding new DNA nucleotides to
the template strand.

Cancerous Tumors
Malignant
Benign
Malignant tumor cells
divide and spread to
Normal adjacent tissues and to
distant tissues through
cells
lymphatic vessels and
blood vessels
Lymph vessel
Blood vessel
Benign tumor cells
may continue to
divide, but are not
New tumor that has
invasive (they do not
formed in distant
spread from tumor).
tissue by metastasis

Protein Synthesis: Transcription and Translation
Transcription: process by which a gene’s Translation: process by which mRNA
base sequence is converted to mRNA (same directs the production of a protein
language but different media). (conversion to a different language).

Check your Understanding
DNA Replication
DNA sequence
TACAATGCGACGTGC
Complementary DNA A T G T T A C G C T G C A C
G
sequence

Check your Understanding
Transcription and Translation
DNA sequence
TACAATGCGACGTGC
AUGUUACGCUGCAC
mRNA sequence G
Met Leu Arg Cys Thr
Amino acid sequence

Review of RNA Types

Types of Mutations
Normal gene
Point mutation: occurs
when one base pair in
mRNA
the DNA is substituted
Protein Met Lys Phe Gly Ala
for another
Base substitution
Frame shift mutation:
Met Lys Phe Ser Ala
a mutation in which one
base pair is inserted or
Base deletion
Missing
deleted, shifting the
entire sequence
Met Lys Leu Ala His

Bioengineering
Bioengineering or genetic engineering: deliberate modification of the characteristics of
an organism by manipulating its genetic material using special technology or controlled
sexual reproduction; typically done as a means of meeting societal needs, like food and
medicine.
 Genetically modified organism (GMO): an organism whose genome has incorporated one or
more genes from another species.

• =

Genetically Modified Organisms (GMOs)
Artificial selection: intentional
reproduction of individuals in a
population with a desired trait.
 ONLY individuals with desired trait are allowed
to reproduce.
 Domesticated animals (dogs, cats, horses, etc.)
and crops are results of artificial selection.
 These organisms are not considered GMOs even
though they have been bioengineered.
 All DNA is from the same species.

Why the pea?
Model organisms: organisms that
are easy to care of, study, and use
for comparisons to many other
similar species.
Peas as model organisms:
 Small and easy to take care of
 Inexpensive to obtain
 Easily observable traits
 Only 2 variants per trait
 Produce large numbers of offspring
in short amount of time
 Can be manipulated experimentally

Genetics Terminology
Genetics: branch of biology that
focuses on the inheritance of
traits
Heredity: transmission of traits
from parent to offspring;
inheritance
Trait: characteristic of an individual
Gene: a sequence of DNA that
codes for a specific protein
Allele: different versions of a gene

Genotype vs. Phenotype
Phenotype: observable features of
an individual
 Ex. Yellow seeds, white flowers
Genotype: the alleles found within a
particular individual
Codes for
 One allele from mother and one from
father
 Only one allele expressed as the
Genotype Phenotype
phenotype
 Denoted as letters
 Ex: YY or Yy for yellow seeds

Characterizing the Genotype - Homozygous &
Heterozygous
 Dominant allele: allele that determines
the phenotype of a heterozygous
individual; masks the recessive allele.
 Denoted with a capital letter (Y or R).
 Recessive allele: allele whose
phenotype is only expressed in
homozygous recessive individuals;
masked by dominant allele.
 Denoted with a lowercase letter (y or r).
 Homozygous: having the same two alleles of a
certain gene.
 Ex:YY or yy.
 Heterozygous: having two different alleles of a
certain gene
YY Yy yy
 Ex: Yy or Rr.

Mendel’s Findings
1.Peas have two versions, or alleles, of each gene.
 This is also true for many other organisms.
2.Alleles do not blend together.
 Maintain their integrity from generation to generation whether they are expressed or not.
3.Males and females contribute equally to the genotype of the offspring because each
gamete contains only one allele of each gene (haploid).
 When gametes fuse together during fertilization, the offspring gets one allele from each parent per gene.
4.Some alleles are dominant to other alleles.
 When dominant and recessive alleles are found together, the phenotype that is expressed will be that of the
dominant allele.

Check Your Understanding
Provide the genotypic ratio and phenotypic ratio for a cross between
a man with blonde hair, and a woman with black hair who is
heterozygous for the hair color gene. Blonde hair is a recessive trait.
Genotypic ratio:
Phenotypic ratio:

X-Linked Inheritance
 X-linked disorders: genetic disorders caused
by genes found on the X chromosome; can
result from dominant or recessive alleles.
 Ex: color blindness.
 Recessive disorder: genetic disorder that
does not exist in the presence of a functioning
dominant allele; only expressed in
homozygous recessive individuals.
 Autosomal recessive disorder: caused by
recessive genes found on non sex chromosomes
(autosomes)
 X-linked recessive disorder: caused by
recessive genes found on the X chromosome
 Males only need one X chromosome with a recessive
gene
 Not “homozygous” but still recessive

Autosomal Recessive Disorder
Carrier: a person who does not
suffer rom the recessive genetic
disorder but who carries an allele
for it that can be passed along to
their offspring
 Ex. Person heterozygous for
albinism

Autosomal Recessive Disorders
 Sickle-cell anemia: defective
hemoglobin protein causes
sickle cell shape.
 Both mother and father must
have at least one allele for
sickle cell anemia; they must
be carriers or express the
disorder.
Sickle-cell anemia
 25% chance that offspring
will get the disorder if both parents
are carriers.

Autosomal Dominant Disorder
Huntington's disease: a late-life disorder that results in the deterioration of
nerve cells in the brain, leading to eventual loss of functions.
is sick

Check Your Understanding
X-linked recessive disorder
Ex. Hemophilia
Male genotype
In this situation, the female does
X Y
not suffer from hemophilia, but her
father had hemophilia. The male
does not suffer from hemophilia.
X
Predict the chances of having a
male child with hemophilia.
X

Linked vs. Sex Linked
 Linked traits: genes that are located on the same chromosome.
 Sex linked or X-linked traits: genes that are located on the X
chromosome.

Linked Traits
 Almost always inherited
together during meiosis.
 Unaffected by crossing over
because they are located so
closely to each other.
 Linked traits violate
Mendel’s law of
independent assortment.

Polyploidy
 Polyploidy: a condition in which one or more sets of chromosomes have
been added to the genome of a diploid organism, creating a triploid (often
sterile) or tetraploid (often viable/fertile) organism; result of total
nondisjunction.
 Most often seen in plants that self-fertilize; can lead to “seedless” varie
reduced fertility (grapes, watermelons, etc.)
 Not common in animals, except fish and amphibians.

History of Evolutionary Thought
Pre-1800s thoughts on
the Earth and living
things:
• Earth and every living
and non-living thing on
it were created at one
time.
• Earth and living
organisms have not
changed since their
creation.
• The number and types
of organisms that
existed at dawn of
creation have not
changed since then.

Evidence for Evolution
 Fossil record
 Evidence for extinction
 Evidence for diversifica

Evidence for Evolution
Transitional forms:
Intermediate states between
ancestral form and its
decedents
 Archaeopteryx
 Teeth of reptile
 Feathers of bird
 Tail with vertebrae like reptile
 Claws of reptile

Radiometric Dating
Radiometric dating: a technique
used to determine the exact age of
an object by measuring the amount
of decay of radioactive elements
within the object
 Carbon dating
 C12 and C14
 Half life of C14 = 5730 years
 Uranium dating
 Uranium-238 to Lead-206
 Half life = 4.5 billion years

Evidence for Evolution
Homologous structures: structures that are physically similar (but
functionally different) among closely-related groups of organisms
due to a common ancestor.

Evidence for Evolution
 Analogous structures: structures from different species
with similar functions but not due to common ancestry.
 Convergent Evolution: the independent evolution of
similar features in species of different lineages.
 Typically due to species evolving in similar environments

Evidence for Evolution
Embryology: study of development from
Fish
fertilization to fetus stage
Salamander
 Similar structures during embryonic
development among vertebrate groups
Tortoise
due to common ancestry
 Pharyngeal gill slits
Bird
 Post anal tail
Pharyngeal pouches
Human
Post-anal tail

Types of Evolutionary Change
 Microevolution: evolutionary change resulting from a change of the
allele frequencies of a population
 Macroevolution: large-scale change occurring over long periods of
time that results in the formation of new species (speciation)
2 species
1 species
Time

How does microevolution occur?
Population: Individuals of the same species that live in the same
area at the same time and have the potential to interbreed
Four mechanisms of evolutionary change within a population

1. Mutation
2. Gene flow
3. Genetic drift
4. Natural selection

Mutation
Mutation: a permanent change in an
organism’s DNA
 Random
 Organisms cannot will a change.
 Primary way new alleles are created.
 Only mutations that affect sex cells can be inherited.
 Can be positive (beneficial) or negative (harmful)
towards fitness.
 Negative mutations are eliminated from populations over
generations through purifying selection.

Gene Flow
Gene flow: the movement of alleles from one population to another
via migration.
 Random with respect to fitnes
 Occurs through breeding of
individuals from different
populations.
 Can reduce genetic difference
between populations.
 But typically increases genetic
variation in receiving population.

Genetic drift
Genetic drift: a random shift in the allele
frequencies of a population due to death
and/or reproduction.
 Random with respect to fitness
 Most pronounced in small populations Reproduction results in increase in
homozygous recessive individuals
 Can lead to the loss or fixation of alleles
 Fixation: when an allele’s frequency
becomes 100% in a population.

Genetic Drift in Small Populations
Genetic bottleneck: a sudden reduction in the alleles of a
population, which typically results from a sudden reduction of
the population.
Ex. Elephant seals, ch

Natural Selection
Biological fitness: ability of an individual to
produce offspring, relative to other individuals
of the same species in the same environment.
 “Survival of the fittest” = survival to reproductive
age
Adaptation: heritable trait that increases the
reproductive success of an individual relative to
individuals lacking that trait in the same
environment.
 Adaptations do not occur because of random
chance.

Natural Selection
 Natural selection: the process by which individuals with certain
heritable traits tend to produce more surviving offspring than do
individuals without those traits.
 Natural selection is a non-random adaptive process.
 “selects” for traits that increase chances of survival in a certain environment.

Natural Selection: Peppered Moth
Peppered moth:
 Two morphs
 Gray with black spots
 Black
 Limiting factor: predation
In 1848, gray morph ≈ 98% of population; by
1900, black morph ≈ 95% of population
 Industrial revolution:
 Coal factories covered forests in soot
 Increased environmental standards since
then have led to an increase in gray
morph again.

Evolution After Geographic Isolation
Allopatric speciation: speciation that results from the geographic
isolation of populations by a barrier that prevents interbreeding
between populations

Speciation Without Isolation
Sympatric speciation: speciation
without geographic separation; mix
of natural and sexual selection.
 Ecological niche: the role of a
species within its ecosystem (e.g.
diet, diurnal/nocturnal, etc.).
 If multiple niches are available in an
area, a population does not need to be
separated for reproductive isolation to
occur.
 Cichlids in Lakes Victoria, Malawi, and
Tanganyika

Sympatric Speciation - Polyploidy
• Polyploidy: when an organism contains more
than one set of paired chromosomes; a result of
nondisjunction; can lead to speciation.
• Most common in plants (self-fertilization).
• Can happen naturally in the wild or artificially
by humans.
• Typically results in infertile (seedless)
varieties with larger fruits.

Adaptive Radiation
Adaptive radiation: process in
which organisms rapidly speciate,
especially when exposed to a new
environment with different
challenges, new resources, and
available niches.
 After mass extinction events
 Cambrian explosion (~500 mya)
 Archipelagos
 Galapagos finches
 Hawaiian honeycreepers

Different Levels of Study in Ecology
Ecology: Study of the interactions that living things have
with each other and with their environment
Individuals: study of individual organisms within an
environment
Population: all the members of a single species living in
the same geographic area at the same time
Community: populations of all species that interact with
one another in the same geographic area
Ecosystem: community of living organisms and the non-
living physical environment with which they interact
 Biotic and abiotic factors

Community Ecology
Affect on Affect on
Interactions among different species fitness for fitness for
species 1 species 2
Competition: occurs when individuals use the
Negative Negative
same resources
Predation and parasitism: occurs when one
organism eats or absorbs nutrients from Positive Negative
another
Mutualism: occurs when two species interact
Positive Positive
in a way that confers fitness benefits to both
Commensalism: occurs when one species
Positive Unaffected
benefits but the other species is unaffected

Life History: r-Selected and K-selected Species
r-selected K-selected
 Unstable environment.  Stable environment.
 Fluctuating carrying capacity  Stable carrying capacity
 Small organism size.  Large organism size.
 Little energy used to produce  Large amount of energy used to
each offspring. produce each offspring.
 Many offspring produced.  Few offspring produced.
 Not many survive. Why?  Majority survive
 Short gestation period and early  Long gestation period and late
maturity. maturity (long parental care).
 Short life expectancy.  Long life expectancy.
 Single reproduction in lifetime.  Multiple reproductions in lifetime.

Types of Population Growth
Exponential growth: when a population’s size
increases at a rate proportional to its current size
(i.e. as the size increases, so does the growth
rate).
 Each individual produces 2 or more offspring so
population keeps doubling.
 Forms J-shaped curve on a graph.
 What kind of environment is required for this to
occur?
Logistic growth: the density-dependent
decrease in growth rate as population size
reaches the carrying capacity (K).
 As population size increases, growth rate
decreases.
 Forms S-shaped curve on a graph.
 Birth rate decreases and death rate increases as population
approaches carrying capacity.

Interaction Through Competition
Ecological niche: an organism’s place or
role within a community.
 Space it requires, food it consumes, reproductive
requirements, whether it is food for other
organisms
Competitive exclusion principle: two
species cannot occupy the same ecological
niche in the same area indefinitely, because
one species will always outcompete the
other.
 G.F. Gause - It is not possible for two species to
occupy the same ecological niche in the same

Resource Partitioning
Resource partitioning: The dividing up of scarce resources among species
with similar requirements.
 Can lead to eventual niche differentiation
 Each species focuses on its specific niche space
 One niche now becomes two

Fundamental vs. Realized Niche
Fundamental niche: the full range
of environmental conditions and
resources an organism can
possibly occupy and use in the
absence of competitors.
Realized niche: the part of the
fundamental niche that an
organism occupies as a result of
competitors in the habitat.

Ecosystem Diversity
 Ecosystem services: all the processes through which natural
ecosystems benefit humans. Examples?
 Provide water, food, and building materials.
 Energy production.
 Medicinal benefits derived from plants.
 Pollinators.
 Flood and erosion control.
 Water filtration.
 Recycling of organic materials.
 Nutrient cycling.
 Recreation and cultural services.

Factors that Create the Ecosystems on Earth
Distribution of solar energy:
 Solar energy is greatest at the
equator, making it hot.
 Due to curvature of Earth,
sunlight is spread out over
larger areas near the poles,
making these areas colder.

Factors that Create the Ecosystems on Earth

1. Solar heat causes air to
      warm and rise.
       Warm air holds more moisture
      than cold air.
2. Rising air cools and
      condenses the farther it gets
      from the Earth’s surface.
3. Cooling air loses moisture
      causing rainfall.
       Gaseous water molecules lose
      speed as they cool down and
      become liquid again.

Factors that Cause the Ecosystems on Earth
Hadley cell: large scale atmospheric pattern where warm, wet air rises at the
equator and cools at it moves poleward, with dry air descending at about 30° N
and S latitude.
 Creates subtropical (30°) and polar (90°) deserts and tropical (0°) and temperate (60°)
rainforests

History of Mass Extinction Events
 Five mass extinction
events on Earth.
 Humans are currently
causing the sixth mass
extinction event.

Human Impacts on Biodiversity
Habitat loss: the conversion or transformation
of a natural area into a wholly human-occupied
area of little or no use to wild species.
 Typical conversion method - deforestation.
 Mostly caused by expansion of agricultural
land.
 Palm oil plantations expansion = loss of habitat
for orangutans and others.
 Greatest threat to biodiversity.
 Also leads to more erosion, less water
retention, less oxygen production, and more
carbon dioxide production.

Preservation of Species
Protection of species Captive breeding Seed banks and frozen
and their habitats programs zoos - DNA storage

Preservation of Species - Biodiversity
Hotspots
Requirements:
 At least 1500 endemic plant
species.
 Endemic: species found only
in a distinct geographic area.
 70% loss of original habitat.

Preservation of Species
Protected Areas
 Protection of critical habitat
(like biodiversity hotspots)
 National parks/preserves
 Marine protected areas
 Wildlife corridors
 Restoration of habitats !!
Chaparral Restoration video

Preservation of Species - Carbon Sequestration
 Carbon sink: anything that
absorbs more carbon dioxide
than it releases.
 Ex. Forests (conservation and
reforestation)
 National parks and preserves
 CA has nine national parks
(most of any state in US)
 Reforestation of degraded
forests
 Planting more trees can slow
down global warming AND
create more habitat for a variety
of species (win-win).

Respiratory and Circulatory Systems

Functions of the Circulatory System
 Circulatory/cardiovascular system: organ
system that circulates blood through a network of
vessels, transporting nutrients, gases, and
hormones to cells throughout the body.
 Transport: transports oxygen, nutrients, waste
products, immune system cells, and hormones
throughout the body.
 Temperature regulation: helps maintain a body
temperature that is optimum for metabolic function.
 Vasoconstriction in response to cold.
 Vasodilation in response to heat.
 Protection: immune system cells transported
throughout the body aid in fighting foreign invaders.
 Platelets and white blood cells.

What’s in the Blood?
 Red blood cells (erythrocytes):
oxygen transport.
 Contain hemoglobin.
Leukocyte
 Lack nucleus and most organelles.
s
Why?
 95% of all blood cells in the body.
 1/3 of all cells in the body!
Platelets
 White blood cells (leukocytes):
immune response to disease and
foreign invaders (pathogens).
Pathogen
s
 Platelets (thrombocytes): cell Fibrin threads
fragments that aid in blood clotting.

Hemoglobin
 Hemoglobin: an oxygen-carrying protein made up of four polypeptide
chains.
 Each hemoglobin can transport four oxygen molecules bound to seats of iron
molecules.
What would happen if you had an iron
deficiency?

The Circuits of the Circulatory System
 Heart: hollow muscular organ that pumps blood
through circulatory system by a series of rhythmic
contractions.
 Atria: chambers that receive blood entering heart.
 Ventricles: chambers that pump blood out of the
heart; more muscular than atria because they have to
send blood out of the heart and through the body.
 Pulmonary circuit: circuit of blood flow between
the heart and the lungs.
 Systemic circuit: circuit of blood flow between
the heart and the rest of body.

Exchange at Capillaries
 Capillaries are so small that erythrocytes pass through single-file.
 Gases, nutrients, and waste move via diffusion.

Heart Valves
 Semilunar valve: valve between ventricles and aorta or pulmonary
artery.
 Atrioventricular valve: valve between atria and ventricles; tricuspid
and bic
What is the
purpose of these
valves?

Cardiovascular (Heart) Disease
Kills more than 750,000 people in U.S annually (leading cause of death).
 Hypertension: high blood pressure; wears out your heart and arteries over
time.
 Atherosclerosis: hardening of arteries by accumulation of plaque (low density
lipoproteins - bad cholesterol); can lead to heart attack or stroke.
 Heart attack: damage or death of cardiac muscle due to blockage of coronary
arteries, which supply blood to the heart muscles.
 Stroke: death of nervous tissue in the brain du f carotid
arteries, which supply blood to the brain.
Plaque What is the
best way to
prevent heart
disease?

The Nervous System - Communication
 Nervous system: network of
complex neural pathways (nerves)
with a central processor (brain) that
produces electrical signals to relay
messages throughout the body using
neurons.
 Signals are interpreted and responses
are elicited instantaneously
 Involved in all bodily activities
 Key in maintaining homeostasis
 Ex. Shivering when cold

The Nervous System
Central nervous system (CNS):
portion of nervous system
consisting of the brain and spinal
cord.
 Involved in interpretation of signals
and initiation of response.
Peripheral nervous system (PNS):
portion of nervous system outside
of the brain and spinal cord, which
includes the sensory organs (skin,
eyes, ears, mouth, etc).
 Involved in reception and transduction of
environmental stimuli (external and
internal).

Types of Neurons
Sensory neurons: nerve cells that receive signals from sensory receptors inside and on the
surface of the body, then send that information to the CNS for interpretation.
Interneurons: nerve cells that connect other neurons and relay information between them; only
found in CNS (mainly in the spinal cord).
Motor neurons: nerve cells that transmit signals from the CNS to muscles and glands involved in a
response to a stimulus; elicit an action.

Reflexes Reflex: automatic involuntary response independent of interpretation by the brain. Faster than a reaction (voluntary response that involves the brain, like dodging a ball). Used to test the health of the nervous system. Reflex pathway: Sensory neuron, Spinal cord interneuron Motor neuron Automatic muscle movement

Sensory Receptors Mechanoreceptors: receptors that respond to pressure.

Senses: Touch, hearing, balance.

Thermoreceptors: receptors that respond to changes in temperature.

Senses: Touch, pit vipers’ hunting sense, spicy food (capsaicin receptor).

Chemoreceptors: receptors that respond to different chemical stimuli in the environment.

Senses: Taste, smell, solute concentration (osmoreceptors in our blood detect glucose, oxygen, and carbon dioxide levels).

Photoreceptors: receptors that respond to different wavelengths of light. Sense: Sight (rods and cones).

Touch - Mechanoreceptors, thermoreceptors, and pain receptors Touch receptors in the skin:

Pressure (tactile mechanoreceptors) Pain receptors Activated along with other receptors and elicit a rapid response for protection.

Temperature change receptors (thermoreceptors)