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Final

Study notes for spring semester labs


Department
Biology
Course Code
BIO120H1
Professor
Ingrid L.Stefanovic
Study Guide
Final

Page:
of 11
CHAPTER 6 – Eutrophication
-PURPOSE:
-Aquatic environments susceptible to pollution
oEx. eutrophication: continuous pollution from agricultural run-off or sewage outflows (human or
animal)
Fertilizers and sewage, being high in nitrogen and phosphorous, increase
concentrations to too-high levels and numbers of algae and algae-eaters
Stages
Algal bloom covers water surface, kills plants below from lack of
sunlight
Short-lived algal cells decompose and accumulate
High oxygen levels, green algae predominate; low oxygen levels, cyanobacteria
dominate
Bacteria feed on dead matter, using oxygen and releasing carbon
dioxide and toxic compounds
Aquatic organisms, both plant and animal, deprived of oxygen die
-Experiment
oTo observe the effects of no-fertilizer (control), moderate-fertilizer, and high-fertilizer treatments
on aquatic environment containing phytoplankton and Salvinia
oPhytoplankton
Unicellular, photoautotrophic aquatic organisms, may form multicellular
colonies or filaments
oSalvinia molesta (kariba weed)
Free-floating water fern, pair of leaves above water and connecting stems
and divided leaves below water
Asexual
oWater quality parameters
Conductivity
Total amount of dissolved ions in water, measured in microSiemens/cm (µ/cm)
Polluted waters have higher conductivity than unpolluted waters
Indirect indicator of salinity, detecting chloride ions from salt
Sources: wastewater from sewage treatment plants and septic systems, urban run-off
from roads, agricultural runoff
Dissolved oxygen
Required for cellular respiration
Dissolved in water by diffusion from surrounding air, aeration of water tumbling over falls
and rapids, and photosynthesis
Split from water only by primary producers
Oxygen levels reduced through overfertilization
Biomass of aquatic plants increase, using up much of available oxygen
Dead plants feed oxygen-using bacteria
Nitrate (nitrogen combined with oxygen)
Essential for plant growth
Responsible for inducing growth in coastal plants
Sources: fertilizer runoff, leaking septic tanks and cesspools, manure and
animal wastes, car exhaust discharges
Nitrate and soil being both negatively charged, nitrate rapidly
goes through soil into drainage water
pH
Scale from 0 (highly acidic) to 14 (highly basic)
Usual fish pH tolerance between 5.0 to 9.0
Factors affecting pH
Age – young lakes are basic/alkaline, but
become more acidic for build-up of decaying organic materials that release harmful,
pH-lowering carbonic acid
Chemicals discharged by natural
environment, communities, industries
Phosphorous
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Essential for plant growth
Responsible for inducing growth in
freshwater plants
Stimulate growth of plankton and
aquatic plants in proportion to phosphate concentration
Sources: fertilizers, pesticides,
human and animal wastes, phosphate-rich rocks, wastes from laundries and industries
Turbidity
Optical property of water to scatter and absorb light; light’s ability to pass through
water
Depends on how much suspended material is present – high turbidity when water
cloudy
Causes: plankton, soil erosion
Measured by spectrophotometer, determining amount of light absorbed
Increased turbidity interferes with sunlight penetration, reducing plant growth and
available dissolved oxygen
CHAPTER 7 – Comparative Vertebrate Morphology
-PURPOSE
-Evolutionary significance of bones
oAll vertebrates built from same general body plan, having descended from an ancestral species
-Ecological significance of bones
oUnderstanding functional significance of morphological variation allows inferences about
ecological aspects of a species
-Overview
oVertebrates have bilateral symmetry
oEndoskeleton divided into
Axial skeleton:
Skull houses brain and sense organs
Spine provides rigidity and support to body
Ribs provide sites for muscle attachments, strengthen body wall, protect vital organs
Appendicular skeleton: fins and paired limbs
Responsible for locomotion, handling food, etc.
-Skull
oAnterior portion houses olfactory and taste receptors, teeth
oPosterior portion protects brain, houses auditory apparatus
Where skull attaches to rest of body
oMiddle portion houses visual receptors
oMammalian skull
Skull formed from many bones joined at sutures
Cranial sutures less obvious in small and old mammalian skulls, invisible in birds’
Bilaterally symmetrical
Occipital bones: located at posterior end of skull, where head connects to the rest of the body
Auditory structures: ears, located slightly anterior
Orbital region: eyes, located dorsally
Rostrum: snout, located anterior of orbits
Houses both nasal passage and in most mammals, teeth
Lower jaw: separate part of the skull and joins with skull on the side of skull near the ears
-Braincase
oSize and structure of brain generally increased during vertebrate
evolution
oEstimated from cranium volume and skull size
oFeatures
Foramen magnum: large hole leading into the braincase
Occipital condyles: projections on the edges of the foramen magnum
Joins with first vertebra in the neck
This type of articulation and number of attachment points have changed evolutionarily
No. of
condyles
Brain
size
Mammal 2Large
Bird 1Medium
Frog 2Small
Anterior: mouth
Posterior: tail
Dorsal: top view
Ventral: bottom view
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Cranium: braincase
Avian cranium thinner and lighter than mammalian
Braincase size varies in birds
-Hearing:
oOuter ear: external ear, canal leading into head
Mammalian ears called pinnae
oMiddle ear: eardrum, bones acting as transmitters of sound vibrations
Feature of vertebrate ear evolution: incorporation of
bones, originally in jaw, into middle ear
oInner ear: chamber of parallel canals separated by membranes to convey information from ear
to brain
oFeatures
Mammalian skull’s ear opening located slightly anterior of occipital condyles
Auditory bullae: extensions of the canal protected by bone
Ossicles: a chain leading from eardrum (tympanic membrane) into brain cavity
From outside in, the bones: malleus (derived from the articular bone), incus (derived
from the quadrate), and stapes (derived from the columella)
oBird have only columella in middle ear
Hearing is less developed in birds than in mammals
oFrogs have no outer ear, but possess eardrums on the skin
-Vision
oEyes used to locate prey and predators position and orientation of orbits indicate feeding
ecology of animals
Forward-facing eyes: animal has binocular vision, enabling judgment of
distances
Lateral-facing eyes: animal has good field vision, scanning broad areas
oFeatures
Orbits: eye sockets
Carnivorous mammals have forward-facing eyes
Herbivorous mammals have lateral oriented eyes
Birds have large orbits relative to the skull
Nocturnal birds have very large eyes oriented forward
Frogs have large, dorsally-positioned orbits
Orbit also functions as an extra space for jaw muscles
-Upper jaw
oSnout houses nasal passages, where air is inhaled and scents smelt, and sometimes teeth
Separation of air and food passages
oFeatures
Turbinate bones: curled, honeycomb-esque bones found in nasal passages of mammalian skull
Covered with nasal mucosa over which air passes
Improves sense of smell
Secondary palate: roof of the mouth
Mammalian is fused/complete
Avian is incomplete
Nonexistent in frogs
Premaxilla and maxilla bones: what composes the upper jaw in frogs
Nares: external nostrils of frogs
Amphibians absorb oxygen and eliminate carbon dioxide via
the skin (cutaneous respiration), lining of the mouth (buccal
respiration), and the lungs
-Lower jaw
oFor feeding, along with upper jaw
oHow lower jaw articulates with skull and its shape and size reveals
clues about individual’s ecology
oNumber of bones have changed during evolution
oFeatures
Mammalian:
Outer
ear?
No. of
ossicles
Mammal Yes 3
Bird Yes 1
Frog No 1
Secondary
palate?
Mammal Yes
Bird Yes
Frog No
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