SCIENCE REVIEWER
The Nervous System
•
•
Highly complex part of an animal
Coordinates its actions and sensory information by
transmitting signals to and from different parts of its
body
• Detects environmental changes that impact the
body
• Works in tandem with the endocrine system to
respond
Central Nervous System
• Consists of the brain and spinal cord
• Controls most of the body and mind
Peripheral Nervous System
• Contains all the nerves that lie outside of the
central nervous system
• Connects the CNS to the organs, limbs, and skin
• 12 pairs of cranial nerves and 31 pairs of spinal
nerves
Þ Somatic Nervous System
• Connects the brain and spinal cord to
voluntary muscles
• External environment
Þ Autonomic Nervous System
• Connects the brain and spinal cord to
involuntary muscles (heart, blood vessels,
lungs, etc.)
• Internal environment
2 Divisions of Autonomic Nervous System
Þ Sympathetic System (SyNS)
• It is activated when the body is in a dynamic
role or stress
• “Fight-or-flight Response”
Þ Parasympathetic System (PaNS)
• Maintains body functions and restores the
body to normal or relaxed mode
• “Rest-and-Digest Response”
THE BRAIN
•
Controls most of the functions of the body,
including awareness, movement, thinking, speech,
and the 5 senses of seeing, hearing, feeling, tasting
and smelling.
Cerebrum
• Site of intelligence of the person (perception,
imagination, thought, judgment and decision)
4 Lobes of the Cerebrum
Þ Frontal Lobe
• Personality, emotions, higher-thinking skills
Þ Parietal Lobe
• Somatosensory
information,
attention,
language
Þ Temporal Lobe
• Hearing, language, reading
Þ Occipital Lobe
• Vision, recognition of shapes and colors
Limbic System
Þ Hippocampus
• Storage of new information in memory
• Compares sensory information with what the
brain expects about the world
• Spatial and navigation memories
Þ Amygdala
• Pleasure, fear, addiction, anxiety, depression,
arousal
• Memories of emotional events
Diencephalon
Þ Thalamus
• Relays sensory and motor information to the
cortex
• Consciousness, sleep, alertness
Þ Hypothalamus
• Waking up, adrenaline, water balance,
appetite
• Control of the pituitary gland
• Control of the autonomic nervous system
Glands in the Brain
Þ Hypothalamus
• Master of the master gland
Þ Pineal Gland
• Controls sleep and circadian rhythm
(biological clock)
Þ Pituitary Gland
• Master gland
• Controls growth, temperature, pregnancy and
childbirth
Corpus Callosum
• Connects the two cerebral hemispheres
Midbrain (Mesencephalon)
• Coordinates sensory information with simple
movements
• Tectum, Tegmentum, Colliculi
Colliculus (Reflex Center)
Þ Superior Colliculus
• Movements of the eye, head and neck
response to visual stimuli
Þ Inferior Colliculus
• Movements of the head and trunk in response
to sound stimuli
Myelencephalon
Þ Medulla Oblongata
• Controls the heartbeat blood pressure, and
reflex action (vomiting, coughing, etc.)
Metencephalon
Þ Cerebellum
• “Little Brain”
• Motor control, body coordination, spatial
navigation and balance
Þ Pons
• Controls breathing, facial expressions, dreaming
SPECIAL AREAS OF THE BRAIN
Þ Cortex – surface of the cerebrum
Þ Gyrus/Gyri – folds of the cerebrum
Þ Sulcus/Sulci – spaces between the folds/grooves.
Þ Fissure – deeper grooves than the sulci
Þ Broca’s Area – responsible for producing
knowledge
Þ Wernicke’s Area – helps in speech processing
and understanding language
THE NERVE (Neurons)
• Building block of the nervous system
Classification
1. Location
• Cranial nerves
• Spinal nerves
2. Function
• Sensory neuron (Afferent neuron)
• Interneuron (Associative/relay neuron)
• Motor neuron (Efferent neuron)
Þ Afferent Neurons
• Long dendrites, short axons
• Cell body at the side of the neuron
• Begins with a receptor
Þ Efferent Neurons
• Short dendrites, long axons
• Cell body at the end of the neuron
• Ends with an effector
Neurotransmission
• is the process by which signaling molecules called
neurotransmitters are released by the axon
terminal of a neuron, and bind to and react with the
receptors on the dendrites of another neuron a
short distance away.
How does neurotransmission work?
• Dendrites receive signals that come together and
then the total signal is transmitted to the longest
branch, the axon. The axon carries nerve impulses
from a cell body to the next cell.
Þ Presynaptic Neuron – transmits the signal toward
a synapse
Þ Action Potential – gets generated when the
negative inside potential reaches the threshold
Þ Neurotransmitters – chemicals that allow neurons
to communicate with each other throughout the
body
Þ Synapse/Synaptic Space – the points of contact
between neurons where information is passed from
one neuron to the next
Þ Postsynaptic
Neuron
–
receives
the
neurotransmitter after it has crossed the synapse
Þ Transport Protein – moves other materials within
an organism
Þ Synaptic Vesicle – central role in synaptic
transmission. Stimulus-dependent release of
neurotransmitter
DISEASES AND DISORDERS OF THE NERVOUS
SYSTEM
Alzheimer’s Disease
• Progressive irreversible decline in memory and a
deterioration of various cognitive abilities,
characterized by the destruction of nerve cells and
neural connections in the cerebral cortex
Coma(tose)
• State of unconsciousness, characterized by the
loss of reaction to external stimuli and absence of
spontaneous activity
Epilepsy
• Sudden recurrent seizures caused by an absence
or excess of signaling of nerve cells in the brain
• May include convulsions, lapses of consciousness,
strange movements or sensations in parts of the
body, odd behaviors, and emotional disturbances
Hydrocephalus
• Accumulation of cerebrospinal fluid in the
ventricles, or cavities of the brain, causing
progressive enlargement of the head
Stroke (Cerebrovascular Accident/CVA)
• Sudden impairment of the brain function resulting
either from a substantial reduction in blood flow to
some parts of the brain or from intracranial
bleeding
• Consequences may include transient or lasting
paralysis on one or both sides of the body.
Difficulties in speaking or eating, and loss in
muscular coordination.
The Endocrine System
•
Human organ system that is made up of glands that
make and secretes hormones
• They carry information and instructions from one
set of cells to another
• Regulates how much of each hormone is released
Endocrine Glands
• And organ that. Makes hormones that are released
directly into the blood and travel to tissues and
organs all over the body
Hormones
• Are the body’s chemical messengers
• Helps control mood, growth and development, the
way our organs work, metabolism, and
reproduction
Endocrine Glands in the Brain
Þ Pineal Gland – melatonin
Þ Pituitary Gland
o Anterior Pituitary – growth hormone, thyroidstimulating
hormone,
prolactin,
adrenocorticotropic
hormone,
folliclestimulating hormone
o Posterior Pituitary – Oxytocin, vasopressin,
anti-diuretic hormone
Þ Hypothalamus – dopamine, somatostatin, growth
hormone-releasing
hormone,
gonadotropinreleasing
hormone,
corticotropin-releasing
hormone, thyrotropin-releasing hormone
Endocrine Glands in the Neck
Þ Thyroid – thyroxine (T4), triiodothyronine (T3),
calcitonin
Þ Parathyroid – parathyroid hormone
Endocrine Glands in the Chest
Þ Thymus – usually not active in adulthood/releases
thymosin in children
Endocrine Glands in the Abdomen
Þ Adrenal Glands
o Adrenal
Medulla
–
epinephrine,
norepinephrine
o Adrenal
Cortex
–
glucocorticoids,
mineralocorticoids
Þ Pancreas - insulin
Endocrine Glands in the Reproductive Organs
Þ GONADS
o Ovaries – estrogen, progesterone
o Testes – androgen
The Happiness Hormones
• Hugs and kisses between humans can be used to
display love, kindness, protection and lust. We
generally perform these actions with people we
love which, in turn, leads to the body producing a
number of different hormones.
Þ Dopamine – produced when we feel satisfied,
resulting in feeling happy, excited, and stimulated
Þ Endorphins – helps in reducing physical pain of
injury in our muscles
Þ Oxytocin – helps us to build bond, trust, and
empathy with other human beings
Þ Serotonin - helps in reducing the symptoms of
depression and also regulates our mood
The Human Reproductive System
•
organ system by which humans reproduce and
bear live offspring.
FEMALE REPRODUCTIVE SYSTEM
The female reproductive system has the following
functions:
1. Produces female sex cells (egg cells)
•
The egg cell/ovum is the female reproductive
cell (gamete)
• The egg cell is typically not capable of active
movement, and it is much larger (visible to the
naked eye) than the motile sperm cell.
2. Receives sperm cells from the male
3. Nurtures the development of and provides
nourishment for the new individual
PARTS AND FUNCTIONS
Ovaries
• Female reproductive organs
• Almond-shaped, located on each side of the pelvic
cavity
• It is designed for developing the female
reproductive cells – eggs of ova and producing
female hormones
Fallopian Tubes/Oviducts
• Paired, tubular and muscular organs that run from
the uterus toward the ovary
• The tubal lining is covered by small, hair-like cilia
so that the ovum can move slowly onward
Uterus (Womb)
• Site of egg implantation
• Fertilized egg develops
• Its upper part can be freely movable and can easily
expand during pregnancy when the fertilized egg
develops into an embryo, then a fetus and finally,
to a fully developed infant
• Endometrium – the inner lining, it is shed during the
period
• Myometrium – the thick middle muscle layer of the
corpus of fundus. This expands during pregnancy
to hold the growing baby. It contracts during labor
to push the baby out.
• Uterine Fundus – broad curved upper area in which
the fallopian tubes connect to the uterus.
Cervix
• Located at the end of the uterus
• It is the opening to the uterus
• Cervical canal – spindle-shaped, flattened canal of
the cervix, the neck of the uterus
Vagina
• It is the birth canal leading from the uterus to the
external opening of the reproductive tract
• It receives the penis of male during mating
• It is covered by the external part called vulva –
located between the legs
Vulva
• The outer part of the female genitals
• Includes the opening of the vagina (vestibule), the
labia majora (outer lips), labia minora (inner lips)
and the clitoris
Breast (Mammary Glands)
• Considered accessory organs of the female
reproductive system.
• Supplies milk to an infant in a process called
lactation.
•
The breast is the tissue overlying the chest
(pectoral) muscles
• Made of specialized tissue that produces milk
(glandular tissue) as well as fatty tissue
• The milk-producing part of the breast is organized
into 15-20 sections, called lobes.
• Lobules, where milk is produced
• The milk travels through a network of tiny tubes
called ducts
• The ducts connect and come together into larger
ducts, which eventually exit the skin in the nipple.
• Areola – the dark area of skin surrounding the
nipple
• Connective tissue and ligaments provide support to
the breast and give it its shape. Nerves provide
sensation to the breast. Also contains blood
vessels, lymph vessels and lymph nodes.
MALE REPRODUCTIVE SYSTEM
Testes
• Male reproductive organ
• Source of spermatozoa (sperm) and also of male
sex hormones
• Hangs in a body or pouch called scrotum
Scrotum
• Fold of skin outside the abdominal cavity which
encloses the testes
Seminiferous Tubules
• Highly coiled tubules in the testes that produces
sperm
Epididymis
• Temporary storage place for sperm prior to
ejaculation once the sperm cells are formed in the
seminiferous tubules
• Ejaculation – the release of semen from the penis
Vas Deferens
• Receives the sperm cell from the epididymis,
carries them up and delivers them to the urethra
Urethra
• Same tube that drains the urinary bladder
• Serves as the passageway of sperm and urine to
the external environment
Glands
• Provides liquid in which sperm can swim
Þ Seminal Vesicle – secretes a fluid that makes up
most of the components of the semen
Þ Prostate Gland – secretes a slightly alkaline milky
fluid that is discharged as part of the semen
Þ Bulbourethral Gland – secretes a thick and clear
mucus that lubricates and neutralizes any trace of
acidic urine in the urethra
Penis
• It is the male organ of copulation, is partly inside
and partly outside of the body
• Cylindrical organ through which sperm and urine
can exit the body
• It transfers sperm to the female organ
• Contains erectile tissue
Sperm
• Male reproductive cell and is derived from
the Greek word sperma (meaning seed)
The Menstrual Cycle
•
Refers to the cycle of physiological changes from
the beginning of one menstrual period to the
beginning of the next
Menarche
• First occurrence of menstruation
• Occurs between the ages of 9-16
Perimenopause
• Ovaries produce less estrogen and progesterone.
• Hormone levels fluctuate, periods are getting
irregular in length and frequency. Ovaries may or
may not release an egg.
• Although fertility is declining, you can still conceive.
May last for several years
Menopause
• Point in time when menstrual cycles permanently
cease due to the natural depletion of ovarian
oocytes from aging
• You no longer ovulate and you cannot conceive a
child
Post menopause
• Hormone levels will never again be suitable range
for ovulation and pregnancy. Birth control is no
longer necessary
Menstruation
• Visible manifestation of cyclic physiological uterine
bleeding due to shedding of the endometrium
Menstrual Cycle
• Refers to the cycle of physiological changes from
the beginning of one menstrual period to the
beginning of the next
THE FOUR PHASES OF THE MENSTRUAL CYCLE
Menstrual Phase (3-7 days)
• Starts when an egg is not fertilized. The thickened
lining of your uterus is no longer needed
Follicular Phase (6-7 days)
• Starts from the first day of the period overlapping
with the menstrual phase until ovulation
Ovulation Phase (usually occurs between 12th to
14th day)
• Is the only time during cycle when you can get
pregnant
Luteal Phase
• When the follicles release the mature ovum. The
follicles change into corpus luteum releases
progesterone
FSH – follicle stimulating hormone
LH – luteinizing hormone
FERTILIZATION AND BABY GROWTH
Formation of Twins
Fraternal twins -> dizygotic
• From two separate eggs that are fertilized by
different sperms.
• Hyperovulation – when the ovaries release two
eggs
Identical twins -> monozygotic
• A single zygote splitting to form two separate
embryos with identical genetic material. They have
identical DNA and share a lot of physical traits.
Heredity : Inheritance and Variation
DNA
• recipe for synthesizing protein
• contains the instructions for making proteins within
the cell
• Proteins are essential nutrients for the human
body. They are one of the building blocks of body
tissue and can also serve as a fuel source
Nucleic
Acids
• Guanine
• Adenine
• Cytosine
• Thymine
• Uracil
Chargaff’s Rule
The amount of Adenine = The amount of Thymine
The amount of Guanine = The amount of Cytosine
DNA REPLICATION
•
Process by which a double-stranded DNA
molecule is copied to produce two identical DNA
molecules
• Replication is an essential process because,
whenever a cell divides, the two new daughter cells
must contain the same genetic information, or
DNA, as the parent cell
Leading Strand
• Runs from 5’ to 3’ direction, forming a continuous
strand
Lagging Strand
• Runs from 3’ to 5’ direction, forming fragments
Antiparallel
• DNA is made up of two strands that is oriented in
opposite directions
Okazaki Fragments
• Short sequences of DNA nucleotides which are
synthesized discontinuously and later linked
together by the enzyme DNA ligase
Semiconservative
• After replication, there will be two double helix DNA
molecule that contain one old DNA strand and one
newly made strand
Enzymes
Þ Topoisomerase – stops the DNA strand from
supercoiling
Þ Helicase – “unzipping enzyme” – unwinds the DNA
Þ SSB Proteins – single-stranded binding proteins
bind to the DNA strand to keep them separated
after helicase unwinds it
Þ RNA Primer and Primase – primer enzyme,
synthesizes short RNA sequences. Stands as
starting point for DNA synthesis
Þ DNA Polymerase – “builder” enzymes that create
DNA molecules by assembling nucleotides
Þ Ligase – “gluer” facilitates the joining of the DNA
strands together by catalyzing the formation of
phosphodiester bond (chemical bond that forms
when two hydroxyl groups in phosphoric acid react
with a hydroxyl group on other molecules forming
ester bonds)
Errors in Protein Synthesis
Types of RNA
Þ mRNA – Messenger RNA
• encodes amino acid sequence of a
polypeptide
Þ tRNA – Transfer RNA
• Brings amino acids to ribosomes during
translation
Þ rRNA – Ribosomal RNA
• With ribosomal proteins, makes up the
ribosomes, the organelles that translate the
mRNA
Genetic Code
• Chart of 64 triplets of nucleotides
Codon
•
Sequence of three nucleotides that together form a
unit of genetic code in a DNA or RNA molecule
Anti-codon
• Sequence of three nucleotides forming a unit of
genetic code in a transfer RNA molecule,
corresponding to a complementary codon in
messenger RNA
Transcription
• Process by which genetic information encoded in
DNA is copied onto mRNA
Translation
• Process by which information encoded in mRNA is
used to assemble a protein
MUTATION
• An alteration in the nucleotide sequence of the
genome of an organism
• The changing of the structure of a gene, resulting
in a variant form that may be transmitted to
subsequent generations
• Change in a DNA sequence
Causes of Mutation
Þ Natural/Spontaneous Mutation – DNA copying
mistakes during cell division
Þ Induced – exposed to ionizing radiation, mutagens,
or viral infections
Types of Mutation
Þ Number of DNA Sequence Involved
• Small-scale (Genetic)
o Change in one or more bases in the DNA
sequence
o Point Mutation, Frameshift, Substitution,
Inversion
• Large-scale (Chromosomal)
o Large chunks of DNA are inserted,
repeated or lost
o Duplication,
deletion,
translocation,
inversion, polyploidy, aneuploidy
Þ Nature of DNA Sequence
• Somatic
o Mutation in body cells (error in DNA
replication before mitosis)
• Germline
o Mutation in sex cells (error in DNA
replication before meiosis)
Small-scale mutation (DNA/Protein)
Þ Point Mutation
• Silent
• Nonsense
• Missense
Þ Frameshift Mutation
• Deletion
• Insertion
Þ Substitution
Þ Inversion
Large-scale Mutation (Chromosome)
Þ Change in Chromosome Structure
• Inversion
• Duplication
• Deletion
• Insertion
• Translocation
Þ Change in Chromosome Number
• Aneuploidy – abnormal chromosome number
(extra or fewer)
• Nondisjunction – the failure of homologous
chromosomes to separate properly during
meiosis
o One less: 45 (Monosomy)
o One extra: 47 (Trisomy)
• Polyploidy – abnormal number of chromosome
sets
o 1 extra set: 3n (Triploid)
o 2 extra sets: 4n (Tetraploid)
*Lethal in humans, beneficial in plants
Karyotype
• Diagram of a complete set of chromosomes of a
cell or an organism
Disorders Caused by Germline Mutation
Turner’s Syndrome (44-XO, 45)
• Short,
stocky,
with
broad
flat
chest,
underdeveloped ovaries, oviducts and uterus
• Low to normal intelligence, weak in math and
space perception
• Can live fairly normal with hormone supplements
Poly-X Syndrome / Superfemale (44-XXX, 47)
• Tall stature
• Vertical skin folds that may cover the inner corners
of the eyes (epicanthal folds)
• Delayed development of speech and language
skills
• Weak muscle tone (hypotonia)
• Curved pinky fingers (clinodactyly)
• Behavior and mental health problems
• Premature ovarian failure or ovary abnormalities
• Constipation or abdominal pains
Klinefelter Syndrome (44-XXY, 47)
• Lower IQ than sibs
• Tall stature
• Poor muscle tone
• Reduced secondary sexual characteristics
• Gynecomastia (male breast)
• Small testes/infertility
Jacobs Syndrome / Metamale (44-XYY, 47)
• Extra tallness
• Defect of learning
• Weak bones
• Hard time speaking
• Hypotonia
• Small penis and testicles
• Lack of the ability to grow hair on face or body
• Infertility
• Sex drive is decreased
• Emotional problems
Disorders Caused by Germline Mutation
X-Linked Disorders
• Color-blindness
• Hemophilia
• Hypertrichosis
Disorders Caused by Somatic Mutation
Þ Autosomal Dominant Disorder – achondroplasia,
polydactyly, syndactyly, polysyndactyly, vitiligo,
familial
hypercholesterolemia,
cri-du-chat
syndrome
• Males and females can be affected
• Male-to-male transmission can occur
• Males and females transmit their trait with
equal frequency
• Successive generations are affected
• Transmission stops after a generation in which
no one is affected
Þ Autosomal Recessive Disorder – albinism, cystic
fibrosis, sickle cell anemia
o Trisomic Disorders – Mosaicism Syndrome
(Trisomy 9), Patau Syndrome (Trisomy 13),
Edward’s Syndrome (Trisomy 18), Down
Syndrome (Trisomy 21)
• Males and females are affected
• Affected males and females can transmit the
gene, unless it causes death before
reproductive age
• The trait can skip generation
• Parents of an affected individual are
heterozygous or have the trait
Principles of Evolution
THEORIES ON THE ORIGIN OF LIFE
Oparin-Haldane Hypothesis
• Aleksandr Oparin (Materialistic Theory) and JBS
Haldane (Physicochemical Theory)
• The origin of life on Earth is the result of a slow
process of chemical evolution that probably
occurred about 3.8 BYA
Þ Chemical Evolution Theory
• Postulates: spontaneous generation of life, under
the present environmental conditions is not
possible
• Earth’s surface and atmosphere during the first
billion years of existence, were radically different
from that of today’s conditions
• The primitive Earth’s atmosphere was a reducing
type of atmosphere and not oxidizing type
• the first-time life arose from a collection of chemical
substances through a progressive series of
chemical reactions
• solar radiation, heat radiated by Earth and lightning
must have been the chief energy source for these
chemical reactions to occur
*Backed-up by science
Þ The Miller-Urey Experiment
• Proposed by Stanley Miller and Harold Urey
• Experiment which supported the theory of
chemical evolution
•
Showed that simple organic compounds of
building blocks of proteins and other
macromolecules can be formed from gases with
the addition of energy
Spontaneous Generation (Abiogenesis)
• Aristotle
• Living organisms could arise suddenly and
spontaneously from any kind of non-living matter
Biogenesis
• Louis Pasteur
• All living organisms arise from pre-existing life
forms
Uniformitarianism (Gradualism)
• James Hutton
• Natural forces that are now changing the face of
the Earth’s surface has been acting upon the planet
since the beginning in much the same way
Catastrophism
• Georges Cuvier
• There have been several creations of life by God,
each preceded by a catastrophe resulting from
some kind of geological disturbance, with each new
life forms different from the previous one
Panspermia (Cosmozoic)
• Fred Hoyle and Chandra Wickramasinghe
• Life has reached Earth from other heavenly bodies
such as meteorites, in the form of highly resistant
spores of some organisms
Creationism
• All different life forms that occur today were created
by “God)
THEORIES OF BIOLOGICAL EVOLUTION
Evolution
• All about the changes that have transformed living
things from the simplest forms to the diverse
organisms that exist today
o continuous (but gradual)
o changing
o mutation
Geologic Time Scale
•
A system of chronological dating that classifies
geologic strata in time
• The ‘calendar’ for events in Earth’s history
o Eons
o Eras
o Periods
o Epochs
o Ages
Þ Paleozoic Era: Age of Marine Life (540-252 MYA)
Þ Mesozoic Era: Age of Dinosaurs (252-66 MYA)
Þ Cenozoic Era: Age of Animals (66 MYA-present)
Darwinism
• Charles Darwin
• Principle of Natural Selection
o In nature, organisms with desirable traits may
survive while those with weaker traits may not
Þ Struggle for Existence – competition for food and
space
Þ Survival of the Fittest – ability of an organism to
survive and produce offspring
Þ Adaptation – an organism becomes better suited to
its environment
o Structural Adaptation – change involving a
physical aspect of an organism (camouflage,
mimicry, thick furs)
o Physiological Adaptation – change in a species’
bodily function (feedback mechanisms, poison
production, reflex actions)
o Behavioral Adaptation – change affecting the
way an organism naturally acts (migration,
hibernation, phototropism)
• Endangered
o The condition of species becoming less in
population
• Extinct
o The condition of species that perish or are gone
forever
Lamarckism
• Jean-Baptiste De Lamarck
Þ Theory of Need
o Body structured develop because of the need to
survive
Þ Theory of Use and Disuse
o Body structures develop because they are used
extensively
o Body structures do not develop because they
are not used
Þ Theory of Acquired Traits
o Body structures develop to the next generation
due to developed traits
EVIDENCE OF BIOLOGICAL EVOLUTION
Direct
• Fossil records (Paleontology/Archaeology)
o Earliest: Pre-Cambrian Era
o Found in: Sedimentary Rocks
o Types: (1) Petrified, (2) Imprints/Impressions
Indirect
•
Comparative Anatomy – homologs, analogs,
vestiges
• Embryology – embryonic development of different
species
• Biochemistry – genomic DNA (protein similarity)
• Biogeography – species distribution Worldwide
Archaeopteryx Fossil
• Transitional fossil between dinosaurs and birds
Homologous Structures
• Species having the same structure, but differ in
function
Analogous Structures
• Species having different structure, but similar in
function
Vestigial Structures
• Structures in the human body with no apparent
use/function
Common Descent/Ancestry
• The more similar the Genomic DNA sequence of
different species, the more that they are closely
related to one another
Biogeography
• Study of the distribution of plants and animals to
determine how and where different species migrate
Theodosius Grygorovych Dobzhansky
• Prominent Ukrainian-American geneticist and
evolutionary biologist
• Central figure in the field of evolutionary biology for
his work in shaping the modern synthesis
Population Ecology
BIODIVERSITY
• The variety of species found on Earth including the
geographic locations they are found in
Philippine Biodiversity Laws
Þ PD 1152 – Philippine Environment Code
Þ RA 9147 – Wildlife Protection Act
Þ RA 8485 – Promotion of Animal Welfare in the
Philippines
Þ PD 389 – Forestry Reform Code
Þ ACT 2590 – Protection of Game and Fish
Þ RA 7900 – High-value Crops Developmental Act of
1995
Þ RA 8371 – Recognizing the Rights of Indigenous
Cultural Communities/Indigenous
People
CATEGORIES SPECIES’ VALUE
Direct Economic Value
• Products are sources of food, medicine, clothing,
shelter, and energy
Þ Crops as food source
Þ Medicinal plants
Þ Fruit-bearing trees
Þ Lumber
Indirect Economic Value
• Benefits produced by the organism without using
them
Þ Trees
Þ Cycled materials in the soil
Aesthetic Value
• Provides visual or artistic enjoyment
Þ Forested Landscape
Þ Natural park
Þ Prayer Mountains
POPULATION CHANGES
• Have implication on two very important concerns in
maintaining the stability of an ecosystem
Þ Resource consumption
Þ Biodiversity conservation
Population
Þ Population Ecology
o Inhabitants of a particular area
o A group of interbreeding members of the same
species
Þ Demography
o the total number of people living in a region or
country
Population Increase
Þ Birth/Natality Rate
o Ratio of total lice births to total population in a
specified area over a specified period of time
Þ Immigration
o Species moving into a different location to live
there
Population Decrease
Þ Death/Mortality Rate
o Rate at which a particular species or population
dies, whatever the cause
Þ Emigration
o Species leaving a place/region in order to live
somewhere else
Population Increase = (BR + IMG) – (DR + EMG)
Population Growth = (Pop. Increase/Org.
Population) x 100%
New Population = Pop. Increase + Original Pop.
Population Density
• the number of organisms per unit area of place
• Population Density = Pop/Land Area (km^2)
FACTORS AFFECTING POPULATION GROWTH
Density-Dependent
• Factors that regulate population growth and
influenced by population density
Þ Diseases and parasites
Þ Competition for resources
Þ Predation
Þ Migration (Emigration and Immigration)
Density-Independent
• Factors that do not directly influence changes in
population growth
Þ Natural disasters
Þ Temperature
Þ Sunlight
Þ Human activities
POPULATION GROWTH CURVE
Biotic Potential
• The unrestrained biological reproduction
• The maximum rate at which a population could
increase under ideal conditions
Carrying Capacity
• The maximum number of individuals of a given
species supported by a given area on a sustained
basis