**BSC 116 Final Exam STUDY GUIDE**
Lecture 32: Neurons
Synopsis: neurons convey information from cell to cell
∙ chemical and electrical potential moves across the membrane
o action potential
∙ action potential depends on depolarization of the neuron
∙ connections between cells (synapses) are usually chemical and involve neurotransmitters.
**Animals (1)receive information (2)process (3) respond sensory input (received info) goes into the central nervous system, response is transmitted by the peripheral nervous system
Don't forget about the age old question of What are the characteristics of sound exchange errors (garrett 1975)?
neurons= specialized cells that conduct and store info in the nervous system
Setup If you want to learn more check out What is the preparation of phenols?
∙ Cell body: houses most of cytoplasm, nucleus etc. ∙ Dendrites: branched extensions at receiving end ∙ Axon: extends from neuron to the cell it acts on We also discuss several other topics like What are the functions of the integument?
o Axon hillock: where the axon joins cell body, signal gen.
∙ Becomes electrically excited conduction down axon ∙ Synapse=connection b/t neurons
o Excitement (chemical)
o Synaptic terminal in the presynaptic cell releases neurotransmitters.
o Postsynaptic cell may or may not become electrically excited by the neurotransmitters ∙ Neuron= on/off switch
∙ Inside negatively/positively chargednot
∙ Charge determined by movement of ions
DEFINITIONS: Don't forget about the age old question of What is the difference between recall and recognition?
Sensory neurons=transmit info from sensors that detect external stimuli or internal conditions
Interneurons= from the local circuits connecting neurons in the brain
Motor Neurons= transmit signals to muscle cells
Glial Cells= nourish, insulate and regulate neurons
-Neuron at Rest
membrane potential=voltage difference across cell membrane as a result of unequal
resting potential=membrane potential of a neuron that is not excited
∙ Resting cell maintains K+-Na- gradient
o ATP powered sodium potassium pump
o Ion channels let ions move down their gradients o Net movement of charge is what creates voltage potential
***when a neuron is excited, the membrane potential goes from negative to positive
gated ion channels =respond to some stimulus by opening/ closing
voltage gated ion channels= respond to change in membrane potential
Hyperpolarization= membrane potential more negative If you want to learn more check out What is the difference between the method of agreement and the method of difference?
∙ Depolarization (less negative) of membrane potential activates voltage gated Na+ channels
o Positive feedback: leads to further depolarization and more Na+ channels opening
o Action potential: massive, rapid depolarization
**Action potentials are propagated along axons ∙ During falling phase and undershoot, Na+ channels activated
o Refractory period: time between action If you want to learn more check out What is the goal of the sport management professions?
∙ Signal propagates because action potential in one area of axon depolarizes neighboring region ∙ Activation of K+ and inactivation of Na+ channels during refractory period
∙ Speed of propagation increases with axon diameter and “insulation” by glial cells
**Vertebrates and neurons are insulated by glial cells ∙ 2 kinds of glial cells provide a myelin sheath around axons: electrical insulation
o wrap axons in multiple layers of cell membrane o no leakage to dampen effect with distance o oligodendrocytes in CNS
o Schwann cells in PNS
∙ Insulation allows depolarization to propagate farther/faster
∙ Voltage gated Na+ channels limited to gaps in myelin sheath: nodes of Ranvier
o Depolarization jumps from node to node
**Info passes in chemical form from 1 neuron to another
In vertebrates, chemical synapses more common, NOT electrical synapses
∙ Neurotransmitter=pre-synaptic chemical released by neuron
Presynaptic axon terminal= neurotransmitter packaged into synaptic vesicles
∙ Postsynaptic membrane has ligand-gated ion channels that bind neurotransmitter.
o Binding change in potential
o Excitatory postsynaptic potentials: depolarize membrane slightly
o Inhibitory postsynaptic potentials: hyperpolarize membrane slightly
**The Number and type of synapses determines the response
postsynaptic potentials graded rather than all or nothing
∙ Don’t exceed threshold then fade
∙ Multiple potentials can build up
o Temporal summation- series of potentials from same synapse
o Spatial summation- potentials from different synapse on cell
∙ Inhibitory potentials can cancel out excitatory potentials
Lecture 33: Nervous Systems
-neurons convey information from cell to cell -neurons are arranged into networks
-nervous systems are large networks of neurons
**different taxa= different nervous systems** ∙ Cnidarians: diffuse nerve net
∙ More complex animals: nerves of multiple neurons o Central nervous system (CNS) brain+ nerve cord(s) running body length
Protostomes have ventral nerve cord
Deuterostomes have a dorsal nerve cord
o Peripheral nervous system: ganglia and nerves outside CNS
!!Vertebrate CNS= large brain and spinal cord!!
Brain: is where all stimulus and voluntary behavior is processed
Spinal cord: carries impulses to and from brain -mediates reflexes: involuntary movement
both made of grey matter ( NON-MYELIN) and white matter (MYELIN)
**both derives from hollow dorsal nerve cord
∙ Central canal of spinal
∙ Ventricles of the brain
∙ Both filled with cerebrospinal fluid
Role of glia in the CNS: nourish, support and regulate the functioning of neurons in the brain and spinal cord
Radial glia= embryonic glia that form tracks along which newly formed neurons migrate from the neural tube, the structure that gives rise to the CNS
Astrocytes= facilitate info transfer at synapses and sometimes release neurotransmitters; initiates formation of the blood- brain barrier during embryonic development
Radial glia + astrocytes= can act as stem cells, generating new neurons in glia
Oligodendrocytes= myelinate axons in the CNS Schwann cells= myelinate axons in the PNS Microglia= immune cells that protect against pathogens
Ependymal cells= line ventricles and promote circulation of cerebrospinal fluid
**The PNS carries info to and from CNS*** DEFINITIONS:
Cranial nerves= connect brain with head Spinal nerves= connect spinal cord to rest of body
Afferent neurons= bring info to the CNS (sensory)
Efferent neurons= carry info from CNS
-motor system: skeletal muscles; voluntary (& reflexes)
respond to external stimuli
-autonomic nervous system: smooth and cardiac muscle, glands etc. ; involuntary
sympathetic division: arousal, “fight or flight”
parasympathetic division: calming
“rest and digest”
enteric division: digestion
**Brain begins as 3 bulges of neural tube, develops into
∙ Hindbrain & midbrain
o Brainstem= midbrain+ pons+ medulla Homeostasis, coordination, info sharing
Attention, alertness, motivation
o Cerebellum: coordinates movement, hand eye coordination
o Diencephalon= thalamus+ hypothalamus+ epithalamus
Homeostasis, coord. Sensory info, circadian rythms
o Cerebrum: center for learning, emotion, memory, perception
80% of brain
outer cortex of grey matter
connected by corpus callosum
**Sleep and emotions are locally regulated in the brain
∙ controlled in part by reticular formation:diffuse network of neurons in the core of the brain stem; filters incoming info to determine what gets to cerebellum
∙ more info to cerebellum= more alert/awake ∙ Pons and medulla: regulate sleep
∙ Biological clock: regulates sleep cycles coord. By group of neurons in hypothalamus and melatonin from the pineal gland
∙ Limbic system: borders the brainstem, responsible for emotions includes amygdala, hippocampus and thalamus
**Cerebral Cortex controls things we make decisions about
∙ Sensory info received from thalamus
o Received in primary sensory areasassociation areas to make sensefrontal association area to be acted on
∙ Different functions localized in different areas o Broca’s area: controls muscles in the face, active during speech generation
o Wernicke’s area: active when speech is heard, facilitates comprehension
∙ Lateralization: 2 hemispheres not identical in function
3 Process determine structure of the NS during embryonic development
1.Gene expression, signal transduction, etc. establish structures
2.Huge neuron die-off
a.Not in right place= die off
a.Each neuron initially forms more synapses than needed
b.Gets rid of extra
∙ Learning and memory based on neural plasticity after embryonic development
o synaptic connections weaken or strengthen o memories form by rearranging connections in hippocampus
short term= store stimuli for short period to see if important
long term= rearrangements in cerebral
∙ Long term potentiation-ex. Of how synaptic connections changed
o Frequent excitation of a synapse can make the postsynaptic neuron more sensitive to the
Lecture 34: Sensory and Motor Mechanisms
Synopsis: Different types of receptors code external stimuli as action potentials
EX: chemoreceptors, mechanoreceptors, photoreceptors
4 Stages of getting a stimulus to the brain:
1.Reception: sensory cell detects stimulus
2. Transduction: conversion of stimulus to receptor potential
3. Transmission: if receptor potential initiates action potential
a. Receptor cell- axon or neurotransmitter
b. Strength of stimulus modulates frequency of action potential
c. Integration= processing might begin even before transmission
4. Perception: CNS processing of input from sensory neurons
**Transduction can be modified in 2 ways:
1.Amplification: strengthening the stimulus; adding energy
2.Adaptation: become unresponsive to constant stimulation
Different Types of Sensory Receptors
∙ Chemoreceptors: bind molecules, initiates change in membrane potential
∙ Mechanoreceptors: deformed or moved to sense pressure, stretch, motion etc.
∙ Electromagnetic receptors: detect light, electricity, magnetism etc.
∙ Thermoreceptors: detect heat and cold ∙ Nocireceptors: detect pain, like extreme pressure, chemicals etc.
**Taste and smell both rely on chemoreceptors** ∙ Gustation= taste; detection of tastants in solution
o In animals: taste buds
o In insects: bottom of feet and mouth parts ∙ Olfaction= smell; detection of odorants in air o Mammals: receptors in upper nasal cavity
**Hearing and balance both based on
Hearing= pressure waves in the air deform receptor cells, leads to membrane potential perception of vibrations
∙ Starts with conversion of waves in air to fluid o Outer ear: tympanic membrane (eardrum) vibes o Middle ear: 3 tiny bones transmit
o Inner ear: cochlea receives vibrations
∙ Waves flow down vestibular canal, cause vibrations that stimulate hair cells
o Hair cells releasing neurotransmitter all the time o In one direction- depolarize, in other direction hyperpolarize
∙ Second stimulus has both volume and pitch o Volume- magnitude
o Pitch- frequency
∙ Fish- no need to convert air pressure
o No outer ear- vibes pass from water through body
Lateral line system= mechanoreceptors for detecting low- frequency vibrations perceive the direction and velocity of
water, predators, prey
∙ Insects- have “hairs” that vibrate
o Some have tympanic membrane
**Balance requires sensing orientation relative to gravity and angular momentum**
∙ Many animals have statocysts to sense gravity o Chamber surrounded by ciliated cells
o Statoliths move around as body moves
∙ In mammals. Balance assoc. with ears
o Inner ear has utricle (horizontal) and saccule (vertical)
o Chambers lined with hair cells and little stones (otoliths)
o Tilt head stones move
o Semicircular canals detect angular momentum **Light Detection**
∙ Photoreceptors: cells that detect light
∙ Light detecting organs
o Ocelli: simple cup of photoreceptors
Creates shadow to determine light direction ∙ Single- lens eyes: functions like camera
o 1 opening with a lens to focus light on a field of photoreceptors
∙ Compound Eyes: composed of many detectors, ommatidia
o Each facet has own lens
Lecture 35: Sensory and Motor Mechanisms II Synopsis:
∙ Effector neurons work on muscles
∙ Sliding filament model of muscle function ∙ Contraction is the sum of many twitches ∙ Muscle contraction action
**Complicated integration of signals leads to a specific response
response can act on the endocrine system, muscles
**Skeletal muscle contracts to move skeletal elements
∙ Characteristic organization: linear fibers within fibers o Muscle= bundle of fibers running parallel to bone
o Fiber= single cell (multiple nuclei) with bundle of myofibrils
∙ Sarcomere: basic contractile unit of myofibril o Ends of actin fibers line up at ends: z lines o Middle of myosin fibers: m line
o “striated muscles”: array of adjacent sarcomeres ∙ muscles contract by actin and myosin sliding past each other: sliding-filament model
∙ myosin molecule: long tail and round head o tails of myosin stick together in thick fiber o head is where all the action is
1.Head binds ATP (low-energy configuration) 2.Head hyrolyzes ATP to ADP, uses energy to change shape: head moves forward
3.Head binds to adjacent thin (actin) filament 4.Head releases ADP but holds on to actin a.Changes shape to pull thick filament against thin
5.Binding new ATP causes head to release cycle restarts
***Ca 2+ & regulatory proteins control contraction of muscle fibers***
∙ 2 sets of regulatory proteins are bound to the thin (actin) filaments
o tropomyosin: coils around actin
o troponin complex: arranged along
o proteins block myosin binding-sites: inhibits actin-myosin interaction
∙ Ca2+ in cytoplasm binds troponin complex: results in exposure of myosin binding sites
!!An Action potential myofibril contraction!!
1. With action potential, motor neuron releases acetylcholine (neurotransmitter), binds to receptors on muscle
2. Triggers action potential, transverse tubules (ext. os plasma membrane) carry AP deep into muscle cell 3.AP causes sarcoplasmic reticulum to release Ca 2+ 4. Troponin complex and tropomyosin move out of the way
5. Sarcomere contracts
6. When motor neuron stops firing, Ca 2+ pumped back to SR
7. Troponin complex and tropomyosin move back in the way, fiber relaxes
8. Like action potential, muscle fiber contraction is “ all or –nothing”, twitch
**Whole muscle contraction is the sum of many twitches!!!
∙ Each fiber controlled by 1 motor neuron
∙ Each motor neuron controls many fibers
o Motor unit= all fibers controlled by one neuron All contract together
∙ Strength of contraction depends on # of neurons recruited and the size of the motor units that they control
∙ Rapid AP’s rapid twitches
o Tension may not be lost bt them= tetanus ∙ “twitches” smoothed out by tendons
**Some sort of skeleton is necessary to turn contraction action***
- muscle works in antagonistic pairs
- many animals like mineralized or chitin skeletons : rely on hydrostatic skeletons
Lecture 36: Animal Behavior
∙ sensory activity drives animal behavior ∙ environment and genetics influence behavior ∙ natural selection shapes behavior
o optimal foraging
o mate choice and parental care
o sexual selection
∙ problem of altruism
individual behavior: an action carried out by muscles under control of the nervous system in response to a stimulus
**For many behaviors, a particular stimulus leads to a particular response**
Fixed action patterns: sequence of unlearned acts linked to a simple stimulus
Signal: stimulus transmitted from one animal to another
∙ can be visual, chemical, auditory, tactile ∙ pheremone: a chemical cue often associated with a threat or reproduction
Communication: the transmission and reception of signals between animals
**the environment of an organism can influence its behavior**
innate behavior: traits that are fixed by genotype
individuals with the same genotype can have different behavioral phenotypes
Learning: modifying behavior based on experience
Imprinting: formation at a specific stage in life of a long-lasting behavioral response to an individual or object , includes a sensitive, critical period
**behavior is the result of complex interactions of environment and genotype
Cross fostering studies: offspring of one species raised by another
Twin studies: look at identical twins placed with different foster families
**ALL types of animals are capable of learned behavior**
∙ associative learning- associate one stimulus with another
o classical conditioning: arbitrary stimulus leads to a certain response
o operant conditioning: trial- and- error learning ∙ spatial learning- maintaining an internal map ∙ cognition- reasoning, awareness
∙ problem-solving- devising solutions to proceed past obstacles
o social learning: many animals can learn by observing conspecifics
**The ultimate causes of many behavioral traits are evolutionary***
∙ -optimal foraging
∙ -mate choice and parental care
∙ -sexual selection
∙ foraging= searching for food and eating o optimal maximize bemefit, minimize cost ∙ mating system= length and number of relationships between males and females o different species-----different mating systems/behaviors
monogamy: long-term pair-bonding
polygamy: multiple mated
∙ polygyny: one male, multiple females
∙ polyandry: one female, multiple males
promiscuous: no pair bonding
∙ Sexual selection= a type of natural selection; result of differential mating success when there is competition for mates
o Leads to sexual dimorphism in phenotypic traits: appearance and behavior
Males usually compete to attract females Males physically compete for females
**Altruism presents a problem for the evolutionary theory!!
∙ Altruism: doing something that lowers your own fitness but increases the fitness of others
∙ Inclusive fitness: fitness (REPRESENTATION OF YOUR GENES IN THE NEXT GENERATION) depends on your reproduction and that of your close relatives o William Hamilton’s Rule: rB>C
Weigh the cost/benefit of an altruistic act
Cost- the number of offspring that the act might cost the altruist
Benefit- # of offspring that an action will gain the recipient
R- coefficient of relatedness: avg. # of genes shared by the 2
As long as rB>C, benefit outweighs
Lecture 37: Into to Ecology
Synopsis: dist. of species- globally/locally, global dist. of biomes
**Ecology study of how organisms interact with each other and their environments
∙ Populations: groups of individuals of same species ∙ Communities: groups of populations
∙ Ecosystems: groups of communities
∙ Landscapes: groups of ecosystems
∙ Global: the earth: biosphere
Ecology and Evolutionary Bio
∙ Evolutionary time: populations change to adapt to their environments
∙ Ecological time: response of organisms, populations, etc. to their environments
Ecology and environmentalism
∙ Not the same thing- science v. advocacy
**No species occurs everywhere
∙ Factors that determine distribution
Biotic: other living things
Abiotic: physical factors
Dispersal= movement of individuals to new areas
**organisms may choose to avoid a livable habitat psychological habitat selection
**species distributions are often limited by other species
∙ Species absent b/c other is missing
∙ Species absent b/c other is present
**species distributions are limited by their physiological tolerances.
∙ Temp: too hot/cold
∙ Water: too wet/dry
∙ Sunlight: esp. for photosynthetic organisms ∙ Geology: the inorganic parts of the habitat o Earth is NOT homogenous for abiotic factors o Summarized as climate
**Shape, tilt, etc. of earth results in broad climatic patterns
∙ Surface curved: areas away from equator get less intense sunlight
∙ Pattern of heating/ evaporation: variation in precipitation
∙ Axis rotation tilted 23.5 deg.: seasonal variation in sunlight
∙ Rotation of the earth: circulation of air/ water currents
Local variations in climate
∙ Proximity to water
o Air changes temp faster than water
o Shadow to sunlight
o Altitude and temp
o Rain shadow
∙ Tilt of the earth results in predictable seasonality
Long-term, global variation in climate
∙ Periods differ
∙ Until 15-20k y.a., northern latitudes covered by glaciers
∙ Species move north as climate warms
Biomes: major habitat types, determined by biotic & abiotic factors
-latitudinal variation in temp., moisture, etc. leads to latudinal variation in animals/ plants
Ecotones: areas of transition between biomes **Disturbance community variation, patchiness
!!Aquatic biomes are characterized by salinity and depth!!
∙ 75% of earth’s surface
o freshwater <0.1%
o marine 3%
o pelagic (open) v. benthic (bottom)
∙ most photosynthesis at surface
o photic v. aphotic
Lecture 38: Population Ecology
∙ variation in life histories
∙ exponential growth
∙ logistic growth
∙ density dependence v. independence ∙ metapopulations
**Populations change over time
∙ Population: conspecific individuals occurring in a particular area
∙ Populations are dynamic
o Gain individuals from birth
o Gain individuals from immigration
o Lose individuals from death
o Lose individuals from emigration
∙ 3 characteristics to describe populations: o density= number of individuals per unit area ( or volume)
boundaries difficult to define
various methods estimate size/density ∙ mark recapture
o dispersion: pattern of spacing
o clumped: aggregated in
o uniform: evenly spaced
o random: independent of other
o demographics= age and sex structure of the population
Life table- age specific summaries of survival in population
single cohort construction from birth to death
**Survivorship curve- graphical explanation of life table
∙ number alive plotted vs. each age
∙ species have characteristic survivorship curves depending on life history
reproductive table= fertility schedule
∙ Cost of reptoduction= energy spent on offspring not spent on parent
∙ Iteroparity repeated reproduction; multiple periods
∙ Semelparity big bang reproduction: all reproduction concentrated in a single effort ∙ Trade offs: can’t maximize all reproductive patterns at the same time
!!As long as there are more births than deaths POPULATION WILL GROW!!!
population growth often regulated by feedback
Carrying capacity: number of individuals that a habitat can sistain
-limiting factors=energy, shelter, nutrients, territory
logistic population growth model: incorporates carrying capacity
∙ K selection- for traits helpful at high densities ∙ R selection- for traits helpful at low densities
***Density dependence is ecological feedback***
∙ When birth/death rates change with population size they are density dependent
∙ Equilibrium birth=death
∙ Causes of density dependent regulation o Competition
o Accumulation of wastes
o Intrinsic factors
∙ Versus density-independent
**Population size is dynamic**
**Populations vary in space as well as time**
∙ Populations connected by dispersal in a
o Sources: positive population growth , lots of emigration sinks
o Sinks: negative population growth, lots of immigration from sources required to maintain population
∙ Habitat fragmentationmetapopulation
Lecture 39: Community Ecology
Interspecific Interactions and regulation of community structure
Community: composed of 2+ species in space and time
Ways that species interact in community:
1.Competition: -/- species compete for resources needed for growth, reproduction etc.
2. Predation: +/- one animal eats another
a. Prey adapted to hide
i. Cryptic coloration=camouflage
ii. Aposematic coloration=brightly colored
iii. Batesian mimicry= harmless resemblance iv. Mullerian mimicry= 2 venemous
3. Herbivory: special case of predation, animal eats plant/alga
**Competition results from species overlapping niches**
Niche: sum of the biotic and abiotic needs of a species, its place/role in a habitat
o Wide niche overlaps = competitive exclusion o Narrow niche overlaps= resource partitioning
Character displacement: resource partitioning leads to morphological differences
Symbiosis: close association between species pairs, where at least one species always benefits
Species richness: number of different species ∙ Relative abundance: proportion of individuals that belong to each species
2 communities can have same richness but different structures
∙ -feeding relationships among species
o -energy moves up from lower levels
o -food chain: producers consumers (herb) consumers (carn)
Energetic Hypothesis: inefficiency of energy transfer between levels
Dominant species: most abundant or greatest biomass (total of entire population)
Keystone species: key niches maintaining community structure ; not necessarily dominant
Facilitators: ecosystem engineers
**Communities have top-down and bottom-up regulation**
3 Possible relationships between plants and herbivores
o Increase in P, decrease in H
o Decrease in P, increase in H
∙ Bottom up: PHC
∙ Top down: PHC
**Species richness is maintained by disturbance**
∙ -most communities are not in stable equilibrium ∙ -nonequilibrium model better characterizes most communities
∙ -intermediate disturbance hypothesis: some disturbance increases species diversity
!Succession= pattern of species replacement over time
Ecological succession: first colonizers replaced by other species, which are replaced by other species
Primary succession: beginning without soil Secondary succession: with soil
*large areas have more species: seen in species area curve
latiudinal gradient: more species closer to the equator ; higher tropical diversity
Lecture 40: Ecosystems
Synopsis: flow of energy, cycling of nutrients
Ecosystem: sum of biotic and abiotic interactions in an area
**2 abiotic processes central to ecosystem ecology:
1. Flow of energy
2. cycling of nutrients
!!Both energy and nutrients move through trophic levels!!
Primary producers: autotrophs
Primary consumers: herbivores that eat producers
Secondary consumers: carnivores that eat herbivores
Tertiary consumers: carnivores carnivores that eat carnivores
Detrivores/ decomposers: get energy from detritus (non-living organic material)
**Production is ultimately limited by the amount of energy that enters the system***
∙ primary production: amount of light energy converted to chemical energy in a given span of time ∙ gross primary production: total 1 degree production for an ecosystem
∙ net primary production: part stored as organic matter
∙ Secondary production: new biomass added to consumers; amount of 1 degree production converted to consumer
if plants had all of the needed nutrients, only limited by light ( because of 1 degree)
limiting nutrient: if adding a nutrient increases productivity, then it is limiting
eutrophication: increased algal production due to pollution
**Different nutrients have independent biogeochemical cycles**
∙ Nutrients cycle through ecosystems
o Biogeochemical cycles: biotic and abiotic
o Inputs/ outputs
o Nutrients sometimes present but unavailable ∙ Nutrients can be available/ unavailable,
∙ 4 most important cycles
∙ Decomposition= critical for cycling
∙ Detrivores break down org. molecules to inorg. So they can be used by 1 degree producers
!Humans enrich the Nitrogen cycle for agriculture! ∙ -farming removes N
∙ -fertilizer adds N
∙ -excess runoff
Lecture 41: Biodiversity and Conservation Synopsis: major threats to biodiversity
o -habitat loss
o -invasive species
o -global change
Threats to Biodiversity:
1.Habitat loss and destruction
a. Biggest threat
2.Introduced/ Exotic species
a. From increase in global travel ( introduced) b.Alter ecosystems
c. Accident/ purpose
a. Harvested faster than can reproduce
Human activities habitat degradation/ loss
∙ Agriculture- primary
∙ Natural resource extraction
∙ Urbanization/ infrastructure development ∙ War and violent conflict
Consequences of Pollution
∙ Pollutants not broken down by detrivores=biological magnification: becomes more concentrated in higher trophic levels
∙ Naturally occurring chemicals released at unnatural levels
Invasive Species: An introduced species that extablishes, expands its range, and has a substantial impact on native organisms and ecosystems.
interact with natives as
∙ Fisheries by catch
∙ Collecting for trade
**Burning fossil fuels acid rain
∙ Releases S and N
o Combines with water to make sulfuric/ nitric acids
∙ Kills acid sensitive fish
∙ Source distant from effects
*Chemicals WE release
∙ CFCs- refrigeration, A/C
o Cl reacts with ozone
o Ozone breaks down oxygen
o Less ozone =less UV protection
o DNA damage
**Excess CO2 from fossil fuels and increased temp.
∙ CO2, CH4, H2O naturally warm the earth= greenhouse
∙ Greatest effect at high latitudes
Lecture 42: Conservation Biology
Synopsis: Human population growth, human effects, threats
Ecological footprint: measures Human impact Biodiversity: biological diversity
**anthropogenic (human caused) ecosystem modification is causing increased extinction rates
Biophilia: innate tie to nature
Most common: extinction of species
∙ -preservation of species genetic diversity necessary for future adaptation to changing environment
∙ -community and ecosystem diversity: fates of species interconnected
Lecture 43: Conservation and Restoration
Synopsis: approaches to conservation, restoration ecology, sustainability
***Efforts to protect species revolve around keeping their numbers from getting too low***
∙ Endangered- when population gets too small o Extinction vortex: small populations lead to smaller populations which lead to extinction o Minimum viable population (MVP) size: number of individuals at which a species is able to
sustain its # and not enter the vortex.
Depends on species
o Use effective population size rep. estimated length
!!More efficient to focus on landscapes and habitats than species!!
∙ Areas= multiple species
o Large tracts of land to protect against
Edges: boundaries between communities or ecosystems
Edge effects: increase due to habitat
Corridors: strips of habitat that connect
otherwise isolated habitat fragments,
facilitates movement and dispersal.
∙ Biodiversity hot spots= smaller areas with lots of diversity
Restoration ecology restoring ecosystems too far degraded
∙ Bioremediation: using plants, fungi, prokaryotes etc. to detoxify an area
∙ Biological augmentation: use organisms to add compounds to ecosystem
BSC 116: Final Pre-Test Questions
∙ Ions move in the direction opposite to that favored by the chemical concentration gradient when _____.
o they are pumped by proteins that require ATP hydrolysis and when the electrical charge gradient repulses or attracts them
∙ Choose the set that includes the most charged compounds that are more abundant inside neurons, in the cytosol, than outside the neurons, in the extracellular fluid.
o potassium ions and proteins
∙ The simultaneous arrival of graded depolarization and a graded hyperpolarization of equal but opposite magnitude at a particular location on the dendritic membrane is likely to _____.
o cancel each other out, making it appear as if there was no change in membrane potential
∙ In a neuron, during the depolarization phase that may trigger an action potential _____.
o some voltagegated sodium channels are open
∙ Of these choices, neuronal communication between the brain and the muscles of the leg is best conceptualized as _____.
o electrical and chemical signaling
∙ The plasma membrane of a neuron has voltagegated sodium and potassium channels. What is the effect of membrane depolarization on these channels?
o Membrane depolarization first opens sodium channels and then opens potassium channels.
Membrane depolarization opens both types of channels, but they respond independently and sequentially. Sodium
channels open first, initiating the action potential. As the
action potential proceeds, the sodium channels become
inactivated and remain inactivated until after the membrane returns to the resting potential and the channels close.
Potassium channels open more slowly than sodium
channels but remain open and functional throughout the
∙ If the membrane potential of a neuron decreases, the membrane potential _____.
o becomes less negative.
When the membrane potential of a neuron decreases, the negative value of the electrical potential across the plasma membrane is reduced and the membrane potential becomes more positive.
∙ The fundamental excitable cell in the nervous system is the _____.
∙ The central canal of the spinal cord and the ventricles of the human brain contain a filtrate of the blood, called _____.
o cerebrospinal fluid
∙ As vertebrates evolved, the increasingly complex structure of the brain conferred increasingly complex function, especially apparent in the _____. o cerebral cortex, which is greatly expanded in humans, other primates, and cetaceans
∙ Dolphins can be awake and asleep at the same time because _____. o one side of the brain can sleep while the other side maintains swimming and breathing behaviors
∙ Emotion, motivation, olfaction, behavior, and memory, in humans, are mediated by the _____.
o limbic system
∙ Motor cortex and somatosensory cortex are _____.
o organized in similar manner adjacent to each other, and are anatomically similar from one person to the next
The sensory and motor parts of these cortices are
topographically matched along the border of the frontal and parietal lobes, and are predictably arranged.
∙ In adult humans, shortterm memory relies on connections in the _____ whereas longterm memories appear to be based in the _____. o hippocampus ... cerebral cortex
∙ Addiction onset by cocaine and amphetamines is characterized by increased _____.
o persistence of dopamine in the brain's synapses
∙ Parkinsonism is characterized by the loss of _____.
o dopaminergic neurons
∙ A thermosensory neuron in the skin converts heat energy to nerve impulses via a conversion called _____.
o sensory transduction
The conversion of sensory energy to a change in membrane potential is sensory transduction.
∙ Sensory transduction in the auditory system is much like transduction of _____.
o mechanosensory stimuli
∙ When light first enters the human eye, the first structure that it must pass through is the _____.
∙ Sensory adaptation is apparent when _____.
o a person is no longer aware of a heavy necklace that was put on earlier in the day
∙ The energy for sensory transduction by the lateral line system in fish comes from _____.
o water movements
∙ Rods and cones are similar in that they both _____.
o release glutamate as the primary neurotransmitter
∙ The visual information used by honeybees includes these elements that are not apparent to humans.
o the ability to distinguish ultraviolet radiation and 300 flashes of light per second
∙ The sense described as umami is one of _____.
o savory and delicious sensation on the tongue
∙ Myosin heads have binding sites for _____.
o ATP and actin
∙ Among these choices, the most energyefficient form of animal movement, per kg of body mass, is _____.
o swimming by large fish
∙ An unlearned behavior directly linked to a stimulus that is carried to completion once initiated and is essentially unchangeable is _____. o a fixed action pattern
∙ A learning process that can occur only during a limited period of the individual's development is called _____.
∙ Every morning a graduate student turns on the light in the laboratory and then feeds the fish in the aquarium. After a couple of weeks of this routine, the graduate student notices that the fish come to the surface to feed as soon as the lights are turned on. The behavior of the fish is a result of _____.
o classical conditioning
∙ An individual organism has the option to raise various offspring and/or genetic relatives. Which of the following options represents the greatest genetic success?
o one offspring, one nephew, and two grandchildren
The coefficient of relatedness between parent and offspring is 0.5, the coefficient of relatedness between an individual and a nephew is 0.25, and the coefficient of relatedness
between grandparent and grandchild is 0.25. This gives a
coefficient of relatedness of 0.5 + 0.25 + 0.25 + 0.25 = 1.25. ∙ You observe a large black bird with a shiny black crest engaging in courtship behavior with a little brown bird. It would be reasonable to hypothesize that this is an example of _____.
Both polygynous and polyandrous species tend to be
∙ Which of the following causes Earth's seasons?
o Earth's tilt on its axis
∙ Which of the following investigations is an example of the study of an abiotic factor?
o investigating how the amount of annual precipitation affects the distribution of a tree species
∙ In most cases, the two major climatic factors affecting the distribution of organisms in terrestrial ecosystems are _____.
o water and temperature
∙ What is a biome?
o a major type of ecosystem
A biome is a type of community with certain abiotic
∙ What are the most abundant animals found in the pelagic zone? o What are the most abundant animals found in the pelagic zone? Zooplankton that graze on phytoplankton are the most
abundant lifeforms in the open ocean of the pelagic zone.
∙ To determine the density of a rabbit population, you would need to know the number of rabbits and _____.
o the size of the area in which they live
Density is the number of individuals of population per unit area.
∙ In wild populations, individuals most often show a _____ pattern of dispersion.
Individuals are often found clumped because they are
interacting or are attracted to areas that provide the most
favorable environmental conditions.
∙ Which of the following conditions favors "bigbang" reproduction? o low rates of offspring survival
If the probability of any one offspring surviving is low, then parental fitness is enhanced by maximizing offspring
∙ In the models that describe population growth, r stands for _____. o per capita population growth rate
The growth rate of a population is represented by r, which is equal to per capita birth rate minus per capita death rate.
∙ The number of individuals that a particular habitat can support with no degradation of that habitat is called _____
o carrying capacity
∙ According to the principle of competitive exclusion, two species cannot continue to occupy the same _____.
o ecological niche
∙ The term used to describe a harmless organism resembling a harmful one is _____.
o Batesian mimicry
∙ Cellulosedigesting microorganisms live in the guts of termites and ruminant mammals. The microorganisms have a home and food, and their hosts gain more nutrition from their meals. This relationship is an example of _____.
∙ An organism's "trophic level" refers to _____.
o its food source
∙ Keystone species are those species _____.
o whose absence would cause major disruption in a community ∙ Which of the following best illustrates ecological succession? o Grass grows on a sand dune, is replaced by shrubs, and then by trees.
∙ Caribbean coral reef communities have been strongly influenced by an unknown pathogen that causes whiteband disease. How can the effect of whiteband disease best be described?
o a cascade event that shifts the entire makeup of the community ∙ On a global scale, energy _____ ecosystems whereas chemical elements _____ ecosystems.
o flows through ... are recycled in
∙ Consider this segment of a food web: Snails and grasshoppers eat pepper plants; spiders eat grasshoppers; shrews eat snails and spiders; owls eat shrews. The shrew occupies the trophic level(s) of _____.
o secondary and tertiary consumers
When shrews eat snails (that eat pepper plants), they are secondary consumers. When shrews eat spiders (that eat
grasshoppers), they are tertiary consumers.
∙ The producers in aquatic ecosystems include organisms in which of the following groups?
o Cyanobacteria, algae, plants, photoautrotrophs
∙ Why is a diagram of energy flow from trophic level to trophic level shaped like a pyramid?
o Most energy at each level is lost, leaving little for the next. ∙ Biogeochemical cycles are crucial to ecosystem function because _____. o nutrients and other lifesustaining molecules are in limited supply and must be continually recycled
∙ An ecosystem is unlikely to be limited by the supply of _____ because it is obtained from the air.
Atmospheric carbon, in the form of CO2, is incorporated into living systems by photosynthesis.
∙ In contrast to bioremediation, which is a strategy for _____, biological augmentation _____ a degraded ecosystem.
o removing harmful substances...uses organisms to add essential materials to
∙ Which of the following organisms was/were introduced by humans into the United States or its territories?
o European starling, brown tree snake, kudzu, zebra mussels ∙ The single greatest current threat to biodiversity is _____. o habitat destruction
∙ Which of the following is associated with the smallpopulation approach to species conservation?
o Exctinction vortex, mvp, effective population size
∙ The estimated density or number of individuals needed for a species to maintain or increase its numbers in a region is the _____.
o minimum viable population (MVP)
∙ Hot spots are usually chosen for nature preserves because they _____. o save habitat for threatened and endangered species
∙ Edge species _____.
o may require conditions found in both of the bordering ecosystems ∙ Which of the following statements best describes why ecologists are currently concerned with global warming and the thawing of permafrost in many areas of the tundra biome?
o The bacterial decomposition of thawed organic materials over the widespread areas of the tundra will produce large quantities of CO2, which will add to greenhouse gases and exacerbate global warming.
∙ The effort to develop, manage, and conserve Earth's resources to meet the needs of people today without limiting the ability of future generations to meet their needs is called _____.
o sustainable development