Ecology- Exam 2

waters highest density

4º C

what does algae use float

droplets of oil to help with flotation

what do many fish have to help equalize water density

gas-filled swim bladders

viscosity

fluid thickness causing objects to encounter resistance as they move through water

* water has high viscosity
* streamlined bodies reduce drag

what molecules do aquatic organisms need to build organic compounds

C, H, O, N, P, S (K, Ca)

solutes

dissolved substances in water

semipermeable membranes

allow only particular molecules to pass through

osmosis

movement of water across a semipermeable membrane

osmotic pressure

force where a solution attracts water by osmosis

osmoregulation

mechanisms organisms use to maintain proper solute balance

hyperosmotic

tissues solute concentrations are higher than surrounding water

hyposmotic

tissues solute concentrations are lower than surrounding water

aquatic plants use wet for photosynthesis

bicarbonate (HCO3-) or carbonate (CO3-) because they accumulate in massive quantities

amounts of oxygen gas:

in air= 21%

in water= 1%

countercurrent circulation

adaptation where blood and water flow in opposite directions so that they concentration of O2 in water is always greater than the concentration in blood

anaerobic/anoxic

environment becomes completely devoid of oxygen

thermophilic

bacteria that can live at temperatures up to 110ºC

glycerol and glycoproteins

chemicals present in some animals (arctic cod) that prevent freezing by reducing strength of hydrogen bonds via supercooling

thermal optima

range of temperatures in which an organism best preforms

EX: many fish species in cold waters swim actively and consume oxygen at rates comparable to fish living in warm waters

isozymes

different forms of an enzyme that catalyze a reaction

* having 2+ isozymes suited for different temperature is useful for organisms that must cope with variable temps
* EX: rainbow trout live near streams with cold winters and warm summers

coral bleaching

loss of color in corals as a result of the corals expelling their symbiotic algae (can being when water is 1ºC higher than average- due to warm water)

cohesion

mutual attraction of water molecules; allow water to move through empty remains of xylem cells

root pressure

osmotic potential in the roots of a plant draws in water from the soil and forces it into the xylem; can raise water to \~20 m

transpiration

process where leaves can generate water potential as water evaporates from the surface of leaf cells

cohesion-tension theory

mechanism of water movement from roots to leaves due to water cohesion and water tension

stomata

small openings on leaf surfaces that are points of entry for CO2 and exit points fro water vapor. bordered by guard cells that open and close each stomata

* stops excess transpiration so plants don’t wilt

electromagnetic radiation

energy from sun; packages in small particle-like units called photons

photosynthetically active region

wavelength of light are suitable for photosynthesis (400nm is violet AND 700nm is red)

chloroplasts

specialized cell organelles found in eukaryotic photosynthetic organisms

chlorophyll a

found in all plants. primarily responsible for photosynthesis

chlorophylls b, c, d, f

accessory pigments that capture light energy and pass it to chlorophyll a

carotenoids

reflect orange and red light; allow plants to absorb a wider range of solar energy

C3 photosynthesis photo and disadvantages

common, rubisco, inefficient

* best for cold and wet conditions

C4 photosynthesis

photosynthetic pathway in which CO2 is initially assimilated into a four-carbon compound, oxaloacetic acid (OAA)

derived, Pep and OAA, reactions physically separated

* adapted to warm conditions

PEP: phosphoenol pyruvate

has higher CO2 affinity than Rubisco

CAM (crassulacean acid metabolism) photosynthesis

pathway where the initial assimilation of carbon into OAA occurs at night

* during the day: stomata close to reduce transpiration rates
* stomata open to exchange gas during the night when temperatures are cold and slows transpiration
* adapted to warm conditions

radiation

emission of electromagnetic energy by a surface. increases with the 4th power of absolute temperature

conduction

transfer of kinetic energy of heat between substances that are in contact with one another

convection

transfer of heat by movement of lipids and gases; molecules next to a warm surface gain energy and move away

evaporation

transformation of water from a liquid to a gas state with the input of energy; removes heat from a surface

thermal inertia

resistance to a change in temp. due to a large body volume

homeotherms

organisms maintain constant temperature; allows biochemical reactions to work efficiently

poikilotherms

organisms that don’t have constant body temp.

ectotherms

organisms with body temps. determined by their external environment

endotherms

organisms can generate metabolic heat to rise body temp. higher than the external environment

blood shunting

specific blood vessels shut off so less of an animals warm blood flows to cold extremities where heat would be lost

* happens at pre capillary sphincters

weather vs climate (Temporal variation)

weather: short term variation in temperature and precipitation (hours/days)

climate: long term typical atmospheric conditions through the year, measured over many years

large scale spatial variation VS small scale variation

Large Scale: impacted by factors like climate, land topography and soil type

Small Scale: impacted by factors like plant structure and animal behavior

* often a relationship between space affected and events duration

phenotypic trade-off

situation where a given phenotype experiences higher fitness in one environment, whereas other phenotypes have higher fitness in other environments

phenotypic plasticity

ability of a single genotype to produce multiple phenotypes

* allows organisms to achieve homeostasis if environmental conditions vary

adaptation in enemies

species alter their growth, body shape and behavior in response to the presence of predators

* alterations improve prey fitness by making it difficult for predator to find/consume prey
* plants also have the ability to respond in presence of herbivores

competition for resources

organisms have evolved a variety of phenotypically plastic strategies for high and low competition

* animals spend more time looking for food/alter digestive morphology
* EX: Burmese python stomach because of meat fed once a month

hermaphrodites

individuals that produce both male and female gametes; individuals are able to fertilize their eggs with their own sperm (self compatible)

inbreeding depression

decrease in fitness caused by matings between close relatives due to offspring inheriting deleterious alleles from both eggs and sperm

* b/c of cost, some species wait until self-fertilization becomes the last chance for reproduction

mircohabitats

locations within a habitat that differs in environmental conditions from the rest of the habitats

* EX: desert iguana body regulation between rocks and shade

adaptations to water availability

* plants cannot move: plants close stomata or adjust relative allocations of energy and material to grow longer roots
* animals can move to different microhabitats where water is more available

adaptations to salinity

common strategy is to change the osmotic potential of body fluids by synthesizing large quantities of organic solutes

* EX: rocky tidal pools receive seawater from the splash of high waves

migration

seasonal movement of animals from one region to another

* plastic behavior in response to changing environmental conditions
* EX: monarch butterflies

storage

animals accumulate fat/cache food supplies as a reserve of energy for periods of harsh weather when food is inaccessible

* plants store energy in roots

dormancy

condition where organisms dramatically reduce their metabolic processes

* 4 types!!

diapause (type of dormancy)

involves a partial/complete physiological shutdown in response to unfortunate conditions (common in incets)

* EX: insects in a drought conditions enter diapause by dehydrating themselves

hibernation (type of dormancy)

individuals reduce the energetic costs of being active by lowering heart rate and decreasing body temperatures (common in mammals)

* ex: bears

torpor (type of dormancy)

bread period of dormancy where individuals reduce activity and body temperature; common in birds and mammals

* ex: West Indian hummingbird loses much of the heat in generated the cold temperatures

aestivation (type of dormancy)

shutting down of metabolic processes during the Sumer in response to dry/hot conditions. well-known examples include snails, desert tortoises, and crocodiles

central place foraging

foraging behavior where acquired food is brought to a central place (nest with young birds)

risk-sensitive foraging

foraging behavior that is influence by the presence of predators

* ex: creek chub feed on tubifex worms, but locations with worms also contain more predators

handling time

amount of time that a predator takes to consume a captured prey

optimal diet composition

most animals don’t eat a single food item and base their diet decisions on handling time in addition to the energetic and nutritional value of various resources

* basically you want to eat the most bang for your buck

diet mixing

some foragers consume a varied diet because one type of food might not provide all of the necessary nutrients

life history

schedule of an organisms growth, development, reproduction, and survival; represents an allocation of limited time and resources to achieve maximum reproductive success

fecundity

number of offspring produced by an organism per reproductive episode

parity

number of reproductive episodes an organism experiences

parental investment

time and energy given to an offspring by its parents

longevity (life expectancy)

life span of an organism

slow life history (k- selected)

* long time to sexual mature
* long life spans
* lone number of offspring
* high parental investment
* ex: elephants, oak trees

fast life history (r- selected)

* short time to sexual mature
* short life spans
* high numbers of offspring
* little parental investment
* ex: fruit flies and weeds

life history traits in plants

categorized as:

* stress tolerators- small herbs with long life span, slow growth, and a long time to sexual maturity
* competitors: (goldenrod) grow fast, achieve early sexual maturity, and devote little energy in seed production
* ruderals: grow fast and devote a high proportion of their energy to reproduction

principle of allocation

observation that when resources are devoted to one body structure, physiological function, or behavior, they can’t be allotted to another

optimized life history

revolves conflicts between competing demands of survival and reproduction to achieve maximum fitness

determinate growth

growth pattern where an individual doesn’t grow more once it initiates reproduction; occurs in many species of birds and mammals

indeterminate growth

growth pattern where an individual continues to grow after it initiates reproduction; occurs in many species of plants, invertebrates, fishes, reptiles, and amphibians

tradeoffs of Trinidadian guppies

* guppy common to the streams trinidad
* lower stream reaches, guppies have short life expectancies because they face predation by pike cichlids and killfish
* predator-free, higher elevation streams, guppies have long life expectancies

semelparity

when organisms reproduce only once during their life'; relatively rare in vertebrates, but common in insects and plants

perennial

semelparity examples

aspires when there is a massive amount of energy required for reproduction

* ex: bamboos are semelparous tropical plants that have few opportunities for seed germination
* ex: agaves are semelparous, arid plants that reproduce by growing a giant flowering stalk that produces a large number of seeds

iteroparity examples

* yuccas are mostly iteroparous, but some varieties are semelparous
* varieties live where there is less precipitation, but less chance of fire

senescence

gradual decrese in fecundity and an increase in the probability of mortality

* ex: between ages 30-85, the rates of human metabolism, nerve condition, blood circulation, and breathing capacity decrease up to 65%

why does senescence exist

* inevitable consequence of natural wear and tear
* might reflect the accumulation of molecular defects that fail to be repaired
* rate of wear can be modified by physiological mechanisms that prevent/repair damage

proximate

indirect cues, do not affect fitness directly

ultimate

directly affect fitness

photoperiod

amount of light that occurs each day; provides a cue for many events in the life histories of virtually all organisms

* ex: water fleas in Michigan enter dispose in mid-summer when the photoperiod declines to less than 12 hours of sunlight

sexual reproduction

reproduction mechanism where progeny inherit DNA from 2 parents

gonads

primary sexual organisms in animals

asexual reproduction

reproduction mechanism where progeny inherit DNA from a single parent

vegetative reproduction

form of asexual reproduction where and individual is produced from the nonsexual tissue of a parent

clones

individuals that depend asexually from the same parent and bear the same genotype

pathenogenesis

form of asexual reproduction where an embryo is produced without fertilization

* typically female
* relatively rare in vertebrates

cost of meosis

50% reduction in the number of a parents genes passed on to the next generation via sexual reproduction vs asexual production; occurs because sexual genes are haploid