Final chapters Flashcards
osmosis
the net movement of water from higher water concentration to lower
solutes
dissolved molecules (AAs, sugars, electrolytes)
semipermeable membranes
let some but not all through
aquaporins
channels in the lipid bilayer that facilitate diffusion of water molecules
osmotic pressure
drives water diffusion, cause by difference in concentrations
- the tendency of water to move from one solution into another by osmosis
osmoregulation
regulation of water and solute conc. levels to control osmotic pressure
- animals by balancing H20 and electrolytes (Na, K, Cl)
- salmon major osmoregulation changes: born in freshwater, live life in saltwater, migrate to spawn in freshwater
osmoconformers
keep internal osmotic pressure equal to external enviro (reduces mov’t and energy)
ex. marine animals retain lots of urea to match the external conc.
osmoregulators
organisms who maintain different internal enviro from external.
- skin prevents free flow/passage
- actively maintain diff. osmotic pressure
osmoregulator examples in animals
gills - chloride cells: counter ingestion and diffusion of excess electrolytes - pump Cl out into water, and Na out. In freshwater - pump Na in
sharks and rays - rectal gland: secrete excess salt
marine birds - nasal salt glands excrete salt
shrimp - hypo+hypertonic enviro
paramecia - contractile vacuole (exocytosis)
dehydration of prey
= capture
nitrogenous waste
byproduct/breakdown of proteins and nucleic acids
ammonia
mammals - urea: less toxic
birds and reptiles - uric acid
human nitrogenous waste process
1) filtration into excretory tubules
2) reabsorption (key ions and solutes)
3) secretion of toxic compounds and excess ions
excretory organs in organisms
flatworm - protonephridia : secretory organs
segmented worm - metanephridia
insects, terrestrial arthropods - malpighian tubes (secrete uric acid)
vertebrates/mammals - filter blood through kidneys
kidneys
1) glomerulus
2) renal tubules
3) collecting ducts
4) ureter
5) bladder/cloaca
nephron = functional unit of kidney
(glomerulus, capsule, renal tubes)
deuterostomes
- anus develops first
- radial cell divisions
hemichordates
echinoderms
chordates: cephalochordates, tunicates, vertebrates
hemichordates
seafloor wormlike animals
1) mouth w/ proboscis - elongate protuberance connected to
2) digestive tract by pharynx w/
3) pharyngeal slits - separated by stiff rods of protein
4) dorsal hollow nerve cord
acorn worms - burry in marine sediments
pterobranchs - attach to seafloor and use tentacle to filter feed
echinoderms
seastars, sea urchins, sea cucumbers, sand dollars (7000 species)
1) radially symmetric adult
- bilaterally symmetric larvae
- pentaradial symmetric adults
2) calcium carbonate endoskeleton
3) water vascular system:bulk transport of oxygen and nutrients
- hydrostatic skeleton
4) tube feet: small projections from water vascular system that facilitate locomotion, sensory perception, food capture, and gas exchange
sea cucumber self defense: self evisceration – can regrow intestines
chordate characteristics
1) pharynx w/ pharyngeal gill slits
2) dorsal hollow nerve cord that runs the length of the body, comprised of projections from neurons
- develops from neural tube
3) notochord - stiff, supportive, flexible rod of collagen, runs length of the body
- vertebral column eventually replaces notochord
4) muscular post-anal tail-
- myotomes: series of segments that organizes body musculature
- tail and muscularized appendages (fins + legs)
chordates
1) cephalochordates
2) urochordates (tunicates)
3) vertebrates
cephalochordates
lancelets or amphioxus
- small mobile suspension feeders
- adults burrow in sand, ocean-bottom habitats
- dorsal hollow nerve cord runs parallel to notochord
- notochord stiffens the body
- muscle contractions on either side –> fishlike movement
- no well developed brain or mineralized skeleton
urochordates (tunicates)
sea squirts and tunicates
- notochord, dorsal hollow nerve cord, tail, only occur in larvae or sexually mature forms of motile species
- pharyngeal gill slits - feeding and gas exchange
- siphon-like mouth, anal siphon expels water
vertebrates (craniates)
chondrichthyes
osteichthyes
amphibians
sauropsids
vertebrate characteristics
1) veterbrae - series of hard segments that runs along the main axis of the body, creating the jointed skeleton
2) cranium - protects well developed brain
3) pair of eyes, distinctive mouth, internal skeleton
4) coelom in which organs are suspended - closed circulatory system
5) jaws
6) paired fins
hagfish and lamprey
- cranium but no jaws
- hagfish no vertebral column
- lampreys cartilage along dorsal hollow nerve cord
- lack appendages
chondrichthyes
cartilaginous fish - sharks, rays, skates
- rays and some sharks viviparous: embryos develop inside the female & are attached to the mother by a placenta
- skates and some sharks
oviparous: embryos develop in an egg case external to mother
jaws w/ cartilage skeleton + mineralized teeth - can retain high levels of urea - salt balance
ostelchtyes (bony fish)
bony fish: ray-finned fish,
fleshy-finned fish (8 extant species)
- cranium, jaws, bones from mineralized CaCO3
1) system of movable element in jaws allowing for specialization and diversification of feeding
2) unique gas-filled sac called a “swim bladder” - permits control over position in water via changes in buoyancy (like lungs)
3) kidneys: low water balance regulation occupy water over wide range of salinity
4) fins supported by bony rods
5) bony skeleton
6) stiff but flexible body covering of interlocking scales
tetrapods
11 phyla w/ aquatic and terrestrial - aquatic were earlier
fleshy-finned fish
amphibians
amniotes
fleshy-finned fish
closest relative to tetrapods
- have pectoral and pelvic fins
- include coelacanth (400 mya) and lungfish (bury into wet mud)
amphibians
frogs & toads
salamanders
caecilians (lack limbs)
- habitat: ponds, lakes, or moist terrestrial environments
- must reproduce in water but life cycles parts above water
- external fertilization, oviparous, water dependent egg, metamorphosis
amniotes
amniotic egg : can exchange gases while retaining water - can survive dry, terrestrial habitats
sauropsids (reptiles) and mammals
Edicaran fossils
575 mya
first mammal fossils
simple, fluid-filled tubes
Cambrian fossils
542-489 mya
skeletons of silica, CaCO3, calcium phosphate
- sponges and cnidaria produced calcium phosphate
more fossils
arthropods –> land 420 mya
radiaton of insect + mammal fossils - 360 mya
dinosaurs - 210
key innovations in vertebrate lineage
1) bony exoskeleton
2) jaws
3) bony endoskeleton
4) limbs capable of moving on land
5) amniotic egg
vertebrate jaw
leading hypothesis for origin: natural selection acted on developmental regulatory genes that determine gill arch morphology
evidence:
- jaws and gill arches similar bony or cartilaginous morphology
- muscles that move both structures have the same embryonic origin
- both structures derived from neural crest cells
- regulatory gene expression patterns similar
- gill arch: curved regions of tissue between the gills
teeth = diet specialization
omnivores - diverse array of teeth (meat and plants)
carnivores - large canines
herbivores - premolars + molars
incisors - cut
canines - rip & shear
premolars - shear
molars - grind
vertebrate/craniate characteristics
- cranium + vertebral column
- 2 pairs of appendages
- bone w/ calcium phosphate
- neural crest tissue (brain case)
- well developed circulatory system (with heart)
includes hagfish, lampreys, catrilaginous fish, bony fish (chondrichthyes, ostelchthyes)
reproduction in bony fish
anadromous species: spend adult life in ocean but swim up freshwater streams to breed then die (salmon, some lamprey)
catadromous species: spend adult life in freshwater streams but swim to the ocean to breed (freshwater eels)
sequential hermaphroditism
protogyny - female to male
protandry - male to female
tiktaalik
the organism connecting fish to tetrapods
water to land transition
1) need for support - musculature and skeletal modifications
2) reproductive issues - removal of need for water (internal fertilization and amniotic egg)
3) changes in sensory structures - hearing and sight
4) respiration - lungs for air breathing
5) osmoregulation - kidneys for dealing with nitrogenous wastes
gas exchange organs
aquatic:
external gills
internal gills
terrestrial:
tracheae (grasshopper), spiracle
internal lungs w/ alveoli, bronchi
amniotic egg
albumen - protein-rich solution which cushions the developing embryo and provides nutrients
yolk - nourishes developing embryo
sauropsids (reptiles) adaptations
turtles, lizards and snakes, crocodiles and alligators, birds
1) watertight skin made by a layer of keratinous scales
2) breathe air through well developed lungs
3) lay amniotic eggs enclosed in shells
aves (bird) adaptations
- descended from feathered dinosaurs
- feathers: provide insulation, used for display, furnish the lift, power, and steering needed for flight
- large breast muscles used to flap wings
- lightweight bodies
- bones filled with air sacs
wings and flight
evolved independently in three lineages of tetrapods:
1) pterosaurs (extinct)
2) bats
3) birds
mammal phylogeny (characteristics)
1) hair or fur - insulation
2) endothermy - regulate body temperatures with internally generated heat
3) mammary glands for lactation - ability to provide young with extensive parental care
mammal reproduction (types)
1) monotremes - egg-laying mammals
2) marsupials - pouched mammals
3) eutherians - placental mammals
advantages:
1) offspring develop in a controlled environment
2) offspring are protected
3) offspring are portable
learning
change of behavior as a result of experience
Timbergen’s Questions
1) causation - what physiological mechanisms cause the behavior?
2) development - how did the behavior develop?
3) adaptive function - how does the behavior promote the individual’s ability to survive and reproduce?
4) evolutionary history - how did the behavior evolve over time?
innate behavior
instinctive and carried out regardless of earlier experience
- triggered by specific stimulus
learned behavior
comes from individual’s experience
nature vs. nurture
genetically encoded vs conditioned by environment
methods to determine genetic influence
- crossing closely related species w/ diff behaviors and examining offspring behavior
- molecular studies provide new ways to understand the role of genes in behavior
displays
patterns of behavior that are species specific and tend to be highly repeatable and similar from one individual to the next
fixed action pattern (FAP)
sequence of behaviors that, once, triggered, is followed to completion (continues to end even if interrupted)
- species specific
- no variation in pattern of behaviors, highly repeatable
key stimulus
stimulus that initiates FAP behavior
supernormal stimulus
ex. soccerball w/ goose - exaggerated response - elicits even stronger response
feature dectectors
specialized sensory receptors or groups of sensory receptors that respond to important signals in the environment (ie mating call of certain frog species)
- can recognize own species, and stimulus
hormone
can affect multiple cells in target organs simultaneously
affect example: male courting behavior in lizard species stimulates female hormone production (full dev of ovaries for reproduction) – but castrated male = no testosterone = no courtship stimulus
artificial selection and gene influence on behavior
can alter behavior as well (hunting vs shepherding dog)
- genetically controlled by many genes w/ relatively small effect so difficult to determine which genes control what
for(s) and for(R) determine foraging/sitting in bees and fruit fles
- hormone and receptor gene changed sexual behavior
non-associative learning
learning that occurs in the absence of any particular outcome such as reward or punishment
ex. habituation, sensitization
habituation
reduction or elimination of a behavioral response to a repeatedly presented stimulus
sensitization
the enhancement of a response to a stimulus that is achieved by presenting a strong or novel stimulus first
- weak primary electric shock of aplysia (sea slug) makes a 2nd touch of siphon much more rapid reaction– heightened sensitivity
associative learning (conditioning)
when an animal learns to link (or associate) two events
two types: classical and operant
classical conditioning
(stimulus/behavior association)
two stimuli are paired
ex. meat powder and bell –> bell can cause salivation alone
operant conditioning
(behavior/response association)
linking a behavior with a reward or punishment – generally in young exploring animals, the novel behavior becomes more or less likely
imitation
learning by copying another individual
imprinting
form of learning typically seen in young animals in which they acquire a certain behavior in response to key experiences during a critical period of development – results usually irreversible
ex. ducklings following first animal seen after birth (usually the mom) = filial imprinting
kineses
random, undirected movements in response to stimulus
taxes
movements in a specific direction in response to a stimulus
- magnetotaxis: bacteria detect magnetic fields and swim north
- pigeon navigation: sun as compass, stars at night, detect magnetic field, olfactory, visual cues, biological clock (time & sun orientation)
circadian clock
daily rhythms in animals regulate feeding, sleeping, hormone production, core body temp
- light is primary input
other biological clocks
lunar clock - in tidal enviros
annual clock - cicadas every 13-17 yrs
seasonal clock - photoperiod (day length)
communication
the transfer of information between two individuals - the sender and the receiver
signal types: visual, auditory, electrical, chemical, mechanical
ritualization
the process by which communication has evolved through co-opting and modifying behavior used in another context
1) increasing the conspicuousness of the behavior
2) reducing the amount of variation in the behavior
3) increasing separation from the original function (scent territory marking originally just waste removal)
limited-war strategies
males size each other up/ compare roars in order to asses who’s dominant - avoids fighting in which even the winner may be seriously injrued
deceitful communication
predator to prey, pretending to be bigger, etc.
advertisement displays
behaviors in which individuals draw attention to their status (sexual, territory)
white crowned sparrows song imprinting (communication)
critical time window for learning (10-50 days post hatching)
if song not heard in sensitive period, will not produce song
- song can be learned even with background noise (another species call)
honeybee waggle dance (communication)
indicates how far and in which direction food source is located
within 50m = round dance (circle)
mutually beneficial cooperation
ex: killer whales generate wave together to wash seal (prey) off iceberg because they can’t do it alone
altruistic behavior
self-sacrifices made by individuals for the good of others
Not evolutionarily stable strategy:
- behavior can readily be driven to extinction by alternative strategy
- -group selection easily overthrown by selfish strategy
group selection
natural selection working on groups
– altruistic group would do better than a selfish bunch
reciprocal altruism
individuals exchange favors - can evolve altruism
- vampire females live together - help out w/ food
kin selection
form of natural selection that favors the spread of alleles that promote behaviors that help close relative or kin (depending on the benefits)
direct + indirect = inclusive fitness
Dr. Hamilton’s kin selection formula
B - benefit of behavior to recipient (how many saved)
C - cost of behavior to donor (how many offspring lost)
r - degree of relatedness between recipient and donor
if rB > C, then altruism can evolve
relatedness - likelihood that a gene is shared by common descent
helping sibling have 2 offspring = same fitness as 1 of your own
altruistic kin selection examples
aphids: extreme relatedness
parthenogenic reproduction generates clones, soldier aphids protect colony and don’t reproduce
–> their own genes pass on to next generation by those protected
Hymenoptera (bees, ants, wasps)
– eusocial: overlapping generations in a nest
cooperative care of the young, clear and consistence division of labor between reproducer (Queen) and workers – females are more related to each other than they would be to offspring (males are haploid)
superorganism
single social insect colony in which each individual has a specific role
sexual selection
traits evolved that increase the probability of finding and attracting mates
sexual dimorphisms
pehnotypic differences between the sexes
- -> acts more on males because they generally have to attract mates - females invest more time in offspring and chose which male etc
- -> tables turned: when males incubate offspring, females are brightly colored
intrasexual selection
same-sex competition (often males)
intersexual selection
males compete for female attention
- females choose males based on their advertisement or other way around depending on who raises the offspring
- must be variation in male quality, correlation between trait and quality
population
consists of all the individuals of a given species that live and reproduce in a particular place and is characterized by its size, range, and density
ecology
the study of relationships of organisms to one another and to the environment
factors that influence evolution
abiotic: climate and nutrient availability
biotic: competitors, predators, prey, parasites, organisms that provide food & shelter
logistic growth
exponential then levels off at carrying capacity results in S- shaped curve
1) rate of max reprod of each indiv
2) reflects onset of additional factors (decreasing food and space availability)
ex: rate of O2-hemoglobin binding
intrinsic growth rate
“r” - max growth rate per individual when growth not limited by resources or other factors
3 key factors of a population
1) population size - # of indiv of all ages alive in particular place
2) geographic range - how widely a population is spread out
3) population density - size/range = average density
overdispersed (uniform) population
population more nearly uniformly distributed than would be predicted by chance
exponential growth
the pattern of population increase that results when r is constant through time
intraspecific competition
(members of same species compete) results in natural selection - limits ecological and evolutionary aspects of populations
interspecific competition
(species vs other species) can result in increase or decrease in population size
- can determine size of species’ realized niche
carrying capacity (k)
max # of individuals any habitat can support - interplay between resources and requirements for growth
density-dependent factors
resources, predation, competition, infections
density-independent factors
severe drought, cold
- result in instantaneous drops in population size
- occur at diff starting densities (does not matter)
sampling methods (estimating pop size)
1) hoop + count/lay rope + count - used for sessile organisms
2) mark-and-recapture
age structure
number of individuals within each age group of the pop studied
- growing pop = pyramid structure
- stable pop shows even dist of age classes
demography
study of size, structure, distribution of populations over time, induces changes in response to: birth, aging, migration, death
cohort
group defined as the individuals born at a given time
survivorship
proportion of individuals from initial cohort that survive to each successive stage of life cycle
patterns of survivorship
type I: (humans and large mammals) high throughout then drop at old age
type II: (birds and small mammals) linear-ish decline from the beginning
type III: (herbaceous plants) 2 step – 1) sharp drop 2) very flat slow decline lasts
–> those that survive first stage can age life longer
r-strategists
species that produce large numbers of offspring but little support + resources (energy raising them)
– produce near r-rate, resources unpredictable
(represent an extreme reprod. strategy)
k-strategists
species that produce relatively few young but invest considerable resources into their support (raise young)
- produce near carrying cap rate, resources predictable
(represent an extreme reprod. strategy)
life history
the typical pattern of resource investment in each stage of a given species’ lifetime
metapopulation
a large population made up of a group of independent populations connected by occasional immigrants
patch
a bit of habitat that is separate from other bits by inhospitable environments that are difficult or risky for individuals to cross
- effects of habitat fragmentation on species within them –> narrow corridors between fragments/patches decreases probability of extinction
island
any habitat patch that is surrounded by substantial expanse of inhospitable environment
Theory of Island Biogeography (MacArthur and Wilson)
2 factors determine the number of species that can occupy a habitat island
1) island size - larger islands can support more colonists and extinction rate is lower - larger equil. # species for larger islands
2) distance - more distant islands have lower rates of colonization = lower equil # and species diversity
Georgii Gause (pred/prey)
predators can hunt prey to extinction then die themselves of starvation
Carl Huffaker (pred/prey)
predators and prey can coexist if refuges exist for prey to hide
niche
ecological role played by a species
combo of habitat (abiotic) and population (biotic) - multidimensional habitat that allows a species to practice its way of life
antagonistic interactions
one species benefits at expense of the other
1) competition ( - / - )
2) predation ( + / - )
3) parasitism ( + / - )
terrestrial biomes
broad, ecologically uniform areas distinguished by their climate, soil, and characteristic species
resource partitioning / niche partitioning
divergence within species whose niches overlap in order to minimize the overlap
- diversify eating habits
- temporal solution - grow and bloom at different times
fundamental niche
full range of climate conditions and food resources that permits the individuals in a species to live
realized niche
the actual range of habitats occupied by a species
competition
an interaction in which use of a mutually needed resource by one individual or group of individuals lowers the availability of the resource for another individual or group (not always for food, can be space, etc)
competitive exclusion
one species is prevented from a particular habitat or niche (foxes avoiding large coyotes)
obligate mutualism
when one or both sides of a mutualism cannot survive without the other
(reinforced by natural selection)
facultative mutualism
one or both can survive without the others
commensalism
( + / o ) one species benefits w/ no effect on other
community
set of all populations in a given place
populations within tied by interactions (spot in food web) and physical location - no 2 species have exact same geographical distribution even if same niche
keystone species
species that influences the transfer of a a large proportion of biomass + energy from one trophic level to another OR when one species modifies its physical environment (otters maintain kelp forests)
disturbance
severe physical impacts on habitat diversity reflects frequency and intensity of disturbance
diversity increases when disturbance is frequent or strong enough to limit competition but not limit the number that survive
succession
process of species replacing each other in time
r-strategists pave for k-strategists
climax community
one in which there is little further change in species composition - mature after succession
ecosystem
community of organisms and the physical environment it occupies
food web/ trophic pyramid
depicts movement of carbon through an ecosystem
1st trophic level: primary producers
2nd: primary consumers (herbivores)
3rd: secondary consumers (eat consumers)
top/apex predators: have few predators of their own
decomposers/detrivores: feed on dead bodies/plants and return CO2 and chemicals back to enviro - complete cycle
1000 kg –> 100 kg –> 10 kg –> 1 kg of eagle
rates of primary production
influenced by light, water, and diversity
increased plant diversity = increased rates
Liebig’s Law of the Minimum
primary production limited by the nutrient that is least available relative to its size
mutualism
( + / + ) the benefits to both species outweigh the costs of participation
runaway selection
male trait evolves through sexual selection by female - preference evolves, linked to male trait - can make trait costly and elaborate
predator/prey communication
mechanical - spines
camouflage - avoid detection
aposematic coloration - warning signals
mimicry - mimic poisonous species coloring/patterns
ecological levels
organism (individual) population community ecosystem biosphere
population ecology
studies how and why the size, range and density of a population changes over time
population size equation
change in pop = (births - deaths) + (immigration - emigration)
habitat loss worldwide
tropical rainforest - 16 mil sq km --> 9 mil sq km temperate broadleaf --> lost 94% prarie (US) --> lost 97% wetlands (US) --> lost 54% coastal wetland in Cali --> Lost 75-90%
edge effect
tropical rainforest
inside: clear floor, no wind, dark, humid, life in the canopy
edge: more light and wind, thick vegetation, new ecosystem of underbrush
allows for greater biodiversity
bottom up + top down control
bottom up –> lack of primary producers / lower level organisms leads to starvation of upper level organisms
top down –> lack of predators leads to alternating growth patterns – increase next, decreases next, increases net, etc.
Biomes
tundra alpine taiga temperate coniferous forest deciduous forest temperate grassland desert chaparral savanna rain forest
tundra
north pole, small plants, low diversity
- coldest biome
minimal precipitation and evaporation
alpine
similar to tundra but just under snow-line
- cold and windy
taiga
cool moist forests - rain in summer
conifers and shrubs
temperate coniferous forest
abundant precipitation along pac. coast enormous trees
- interior North Am = less precipitation and colder winter
- drought resistant conifers
deciduous forest
moderate climate 15-20 tree species
maples, oaks, birches, etc.
temperate grassland
fire and lack of precipitation - midwest
desert
south of equator, interiors of continents
- low primary production, few centimeters of precipitation
chaparral
limited precipitation, south of equator
herbs, shrubs, small trees, drought resistant eucalyptus, acacia, oak
savanna
tall perennial grasses, east Africa, souther south am, Australia
- animal diversity can be high
- scattered trees and shrubs
rain forest
moist, highly diverse
north and south of equator
> 300 species per hectare
high temp, heavy rain
latitudinal diversity gradient
diversity peaks near equator (tropics), decreases toward poles
hypothesized reasons for diversity
- have been around for longer
- spread of species = more room for others
- narrow range of enviro variation
- animal pollination
dominican amber fossils 20-30 mya, species interactions with hymenaea tree
Anthropocene era
the time in which we live - reflects the significant impact of humans on the planet
humans growing exponentially
ecological footprint
an attempt to quantify our individual claims on global resources by adding up all the energy, food, materials, an services we use and estimating how much land is required to provide those resources
- amt of land required to support individual at average standard of living
human carbon activity and its effect
burning fossil fuels, deforestation,
–> global warming
CO2 as greenhouse gas - absorved heat energy and then emits it in all directions = heat trap
- climate change consensus: greenhouse effect is the principal cause of observed 20th century temp change
methane and H20 vapor also
climate models
attempts to understand how climate works by fashioning equations that relate a simplified set of variables and interactions
- predicts average 2-5C increase during 21st cent.
- seawater salinity tests for rainfall
- wet places will have more, dry places even less
plant response to global warming
flowers flower earlier, migrate northward
- flowers that have gone extinct could not change flowering time as well
plant evolution/ adaptation to climate change
- can migrate
- assisted migration: the deliberate transplantation of plant populations from existing habitats to new ones more favorable to growth
ocean warming effects
1) coral bleaching - occurs when the symbiotic algae that feed the corals abandon them because of the temp
2) ocean acidification - CO2 levels in ocean lowers pH, more acidic = harder to form calcium chloride shells
alternative energy sources
wind, sun, tidal, nuclear power
reforestation - actively removes CO2 from atm
human fertilizer use
adds 150 mil tons/ years
only 10% ends up in food - rest runoff to lakes and sea
eutrophication
great increase in populations of algae and cyanobacteria where bacteria feed on them
–> leads to O2 depletion by the ocean floor “dead-zones”
decreasing diversity of everglades
- only source of PO4 is through mining - cannot be synthesized
Green Revolution
series of research, development, and technology transfer initiatives that increased agricultural production
corn and wheat production
needs to increase by 15%
earth loses .25% species every year 5000-25000 species
effects of decreased diversity
leads to decreased productivity and resilience
invasive species
can expand dramatically when introduced to new areas often with negative consequences for native species and ecosystems - decimates diversity
evidence of climate change
atmospheric and ocean warming glaciers retreating (increases sea level) 28-98cm by 2100 ice packs thinning migration of alpine tundra coral bleaching permafrost melting pole-ward migration of species climate variation
salmon fishing
- alaskan salmon - historically overfished, now regulated - limited entry permits, only few days, release juveniles etc
- marine reserves
- aquaculture - farmed fisheries
greenhouse gases
1) CO2 - fossil fuels and deforestation
2) methane - agriculture and permafrost (new) 22x more absorption than CO2
3) nitrous oxide - industrial sources and nitrogen cycle, 300x more absorption than CO2
4) water vapor (clouds)
5) fluorinated gase (CFCs)
weather vs climate
weather: short-term fluctuations
climate: long-term trends
viviparous
embryo develops inside female connected by placenta
oviparous
embryos develop in an egg case external to mother
aquatic biomes
> 70% of Earth
- freshwater: lakes, ponds, rivers, streams
- marine (estuary, coral reef, kelp forest, rocky intertidal, open ocean)
biodiversity hotspots
areas with the highest concentrations of Earth’s biodiversity
- kelp forests
- coral reefs
- tropical rainforests
ecosystem stability
resilience - ability of an ecosystem to resist or recover quickly from disturbance – supporting approx same species before and after disturbance
- more diversity and trophic levels = higher stability
