general biology - unit 3

lectures 17 - 21

what is the order of classification of life, including all sub and super categories, from most to least broad?

1. domain
2. kingdom
3. phylum
4. subphylum
5. superclass
6. class
7. order
8. suborder
9. superfamily
10. family
11. genus
12. species
13. subspecies

what are the common characteristics of animals?

* multicellular
* heterotrophs
* no cell walls
* collagen
* mobile

what is bilateral symmetry?

body symmetry in which a central longitudinal plane divides the body into two equal but opposite halves (human)

what is radial symmetry?

body symmetry in which the body is shaped like a pie or barrel and can be divided into mirror-imaged halves by any plane through its central axis (jellyfish)

what is segmentation?

repeated segments dividing an animals body

what is metamerism?

linear series of body segments

what are the advantages of segmentation?

compartmentalization, specialization with respect to bodily regions

what is cephalization?

concentration of sensory equipment at the anterior end of the body (near the head)

what are appendages?

external body parts, such as limbs

are chordates bilaterally or radially symmetrical?

bilateral

what is the notochord?

flexible longitudinal rod between digestive tube and nerve cord of chordata embryos (and some adults)

what are the two groups of vertebrates?

urochordates and cephalochordates

what does the dorsal nerve chord develop into?

central nervous system

what are pharyngeal slits?

* series of pouches separated by grooves along the side of the pharynx
* suspend feeding and gas exchange (gill slits)

true or false: members of the family cephalochordata (lancelets) retain the characteristics of the chordate body into adulthood

true

what characteristic is shared between all members of subphylum vertebrata?

presence of backbone

what do the skeletal and nervous systems of vertebrates allow them to become more efficient in?

* capturing food
* evading predators

what are the derived characters of vertebrates?

* spinal chord
* elaborate skull
* fin rays

what are cyclostomes?

living vertebrates without jaws

what are gnathostomes?

vertebrates with jaws

what were the first mineralized skeletal structures?

conodont dental elements

what do the skeletal support rods in gnathostomes become during development?

jaws

what is the earliest known gnathostome?

placoderms

what is the defining characteristic of class chondrichthyes (sharks, rays, skates)?

skeleton primarily composed of cartilage

what is the defining characteristic of superclass osteichthyes (bony fish)?

ossified endoskeleton with a matrix of calcium phosphate

what organ do most aquatic osteichthyes possess to control their buoancy?

swim bladder

what did gut sacs enable early vertebrates to do?

gulp air to obtain extra oxygen

other than swim bladders, what did gut sacs evolve into?

lungs

what is the defining characteristic of class actinopterygii (ray-finned fishes)?

bone structure shaped as rays in their fins for support

what is the defining characteristic of class sarcopterygii (lobe-finned fishes)?

bone structure reminiscent of tetrapod bone structure, including bones like the radius, humerus, and ulna

what unique features among living fish do coelacanths possess?

rostral organ - part of the electrosensory system, hinge in the jaw

what does a dipnoi’s lung do?

absorb oxygen and remove waste

why do dipnoi’s breathe air through their swim bladder while buried in the mud?

reduce their metabolic rate

what adaptations do tetrapods have?

* four limbs with digits
* neck
* fusion of the pelvic girdle to the backbone
* absence gills
* ears

what are the characteristics of class amphibia?

moist skin for gas exchange, external fertilization of eggs

which classes are amniotes (use amniotic eggs)?

class reptilia and class mammalia

what is an amniotic egg?

egg with a compartment of fluid that bathes the embryo and acts as a hydraulic shock barrier

what is the allantois?

disposal sac in an amniotic egg for certain metabolic waste produced by an embryo

what is the chorion?

membrane in an amniotic egg that exchanges gases between the embryo and the air

what is the amnion?

fluid-filled cavity in an amniotic egg that protects the embryo from mechanical shock

what is the yolk sac and yolk of an amniotic egg?

yolk sac contains the yolk, which is a stockpile of nutrients

what are the characteristics of class reptilia?

* scales containing keratin serving as armor and preventing water loss
* internal fertilization of eggs
* ectothermic (cold-blooded)

what were the original purposes of feathers?

* insulation
* camouflage
* courtship display

what adaptations do class aves (birds) have that allow them to fly?

* lack of urinary bladder
* females have only one ovary
* small gonads
* toothless
* hollow bones

are birds endothermic or ectothermic?

endothermic

what two materials are hairs mostly composed of?

keratin and melanin

what do mammals produce to feed their offspring that no other classes create?

milk (breastmilk)

what did mammals evolve from?

synapsids (mammal-like reptiles)

what is a monotreme and what traits does it have or lack?

* egg-laying mammal
* found only in australia and new guinea
* produce milk but lack nipples

what is unique about marsupials in terms of birth?

give birth to premature offspring, who complete their embryotic development while nursing, held in a marsupium pouch

what is a eutherian or placental species?

* species that has a longer gestational period
* complete embryotic development within the uterus
* joined to the mother by the placenta

what is the placenta and what does it do?

* organ that develops in the uterus during pregnancy
* provides oxygen and nutrients to the baby
* removes waste products from the baby’s blood
* attaches to the wall of the uterus

what is ecology the study of?

interactions that determine the distribution and abundance of organism

what are abiotic components?

non-living

what are biotic components?

living

what is a metapopulation?

spatially separated populations that interact at some level

what is the density of a population?

number of individuals per unit of area or volume

what is the dispersion of a population?

pattern of spacing among individuals

what is species range?

area where a particular species can be found during its lifetime, including where it may hibernate or migrate

what limits species range?

* biotic interactions
* negative effects
* predators
* parasites
* disease
* competitors
* positive effects of interdependent species
* abiotic interactions
* physical or chemical factor
* ex: temperature, water availability

what kind of pattern of dispersion is this?

clumped spacing

what type of pattern of dispersion is this?

uniform spacing

what type of pattern of dispersion is this?

random spacing

what influences clumped spacing?

* resource availability
* behaviour

what influences uniform spacing?

* territoriality
* defense of bounded space
* competitive interactions

when does random spacing occur?

absence of strong attractions or repulsions between individuals

what are the two methods used to determine population size?

* sampling
* mark-recapture

what is sampling?

counting the number of individuals in randomly selected plots, if density is constant, extend density to entire area

what is mark-recapture?

capture a random sample of individuals, mark them, release them, come back and capture another random sample of individuals, see how many of the second round are marked

what is the formula to calculate the estimated whole population using mark-recapture? (s \= individuals marked in first round, x \= number of marked individuals in second round, n \= total number of individuals captured in second round, N \= total number of individuals in population)

N \= sn/x

what is immigration?

movement of individuals into a population

what is emigration?

movement of individuals out of a population

in what conditions does a population grow?

* birth rates exceed death rates
* immigration exceeds emigration

what is exponential population growth?

population free to reproduce at their psychological capacity

what is the formula for exponential population growth? (dN \= change in population, dt \= change in time, N \= number of individuals in a population, ri \= intrinsic rate of natural increase)

dN/dt \= riN

what are the two categories of processes relating to increase in density?

density dependent and density independent

what are density dependent processes?

* limiting resources
* production of toxic wastes
* infectious diseases
* predation
* stress
* emigration

what are density independent processes?

* weather
* natural disasters
* pollution

what is the carrying capacity of a population?

maximum population size that a particular environment can sustain

what are the limiting resources that influence carrying capacity?

* energy
* shelter / refuge
* nutrient availability
* water
* nesting site

what is logistic population growth?

mathematical model of population growth that shows the per capita rate of increase approaching zero as the carrying capacity of the population is reached

what is the formula to calculate logistic population growth? (dN \= change in population, dt \= change in time, r \= rate of increase, K \= carrying capacity, N \= population size)

dN/dt \= rN (K-N)/K

why do lab populations better fit the logistic growth curve?

lack of predators and competitors

what is demography?

study of the vital statistics of populations

what is a life table?

age-specific summaries of the survival patters of a population

what does type 1 of a survivorship curve show?

low death rates during early and middle life and an increase in death rates among older age groups (increasing death rate)

what does type 2 of a survivorship curve show?

constant death rate

what does type 3 of a survivorship curve show?

high death rates for young and a lower death rate for survivors (decreasing death rate)

what is a niche?

all needs of an organism

how does competition affect individuals?

both negative (-/-)

when does interspecific competition occur?

different species compete for a common resource that is in short supply

what is competitive exclusion?

local elimination of one of two competing species

what is resource partitioning?

differentiation of niches between species to avoid competition

what is a fundamental niche?

range of conditions that allows a species to survive, the niche a species would occupy in the absence of competition

what is a realized niche?

range of conditions under which a species actually occurs (caused by resource partitioning)

what is character displacement?

adaptation of a species to the resources now part of their niche (due to resource partitioning)

how does predation affect individuals?

the predator is affected positively and the prey is affected negatively (+/-)

what are the feeding adaptations of predators?

* claws
* teeth
* fangs
* stingers
* poison

what are the defensive adaptations of prey?

* hiding
* running
* camouflage

what is aposematic colouration?

prey with bright colouration tend to signify chemical defense and warn predators