Biology 104 - Exam 3 Flashcards
Echinoderms
- phylum: echinodemata
- bilateral larvae, radial adults, no cephalization, true coelom, complete digestive, no segment, water vascular system
- sea stars, sea cucumbers, sand dollars
water vascular system
system of canals that circulate water
- gas exchange, waste disposal, locomotion, feeding
Chordates
- phylum: chordata
- 4 characteristics –> notochord, dorsal nerve chord, pharyngeal slits, postanal tale
notochord
flexible rod that runs along the back –> spinal discs in humans
dorsal nerve chord
spinal chord and brain
pharyngeal slits
feeding slits
postanal tale
tail (animals i.e. dog/cat), human tail develops away
tunicates and lancelets
- ectotherms
- closest modern day representatives of ancestor chordates
- tunicata: sessile adults, free-swimming larvae
- cephalachordata
- filter feeders
hagfishes
- ectotherms, endoskeleton, slime production
- eat dead/dying animals
- subphyla craniata
lampreys
- endoskeleton of cartilage/bone including backbone or cranium
- jaws of cartilage or bone, ectotherms, cranium and vertebrae
- simplest chordates that have a layer of support surrounding nerve chord
jawed fishes
agile swimmers, most carnivorous, lateral line system
lateral line system
row of sensory organs along body length
cartilaginous fishes
flexible cartilage skeleton, thick/fleshy fins, respiration through the gills, adept predators –> poor eyesight, good smell, electrosensors on head to detect movement of animals
bony fishes
common seas/freshwater, skeleton reinforced by hard calcium salts, keen smell/eyesight, lateral line system, operculum
operculum
gil chamber flap that allows for movement/no movement
ray finned
- fins supported by skeletal rays, gas bladder (buoyancy)
lobe finned
- swim bladder assists in respiration, muscular fins supported by stout bones
- lungfishes, coelacanth
amphibians
- first to inhabit land
- descended from fishes with lungs
- first limbs/lungs –> skeletal support precursor to limbs
- reproduction still tied to water
- adapted to freshwater/land habitats
- improved respiratory organs, circulation, skeleton system, tear glands
- reproduction –> egg + sperm released, metamorphosis
reptiles
- amniotic egg protected by shell
- non-avian reptiles have dry/scaly skin, kidney’s absorb water, well-developed lungs, internal fertilization
- non-avian (ectothermic), birds (endothermic)
birds
- thought to be dinosaur descendants
- powerful breast muscles, keel-like breastbone
- wing shape dependent on habitat
- honeycomb structure of bones makes them light and durable
- some internal organs absent to reduce weight
- high demand for energy –> powerful heart and lungs
- feathers made of keratin –> same as non-avian scales
- insulation, attract mate –> not at all used in flight
monotremes
- platypus, echidna
- lays eggs –> young hatch –> feeds on the mother
marsupials
- brief gestation to live birth
- young develop while attached to mother, usually in a pouch
- kangaroos, opossum, koala
placental mammals
- young develop in womb and have live birth
- placenta joins mother to the embryo
- humans, zebra, elephant, dogs, some aquatic animals
Primates
- evolved from small tree-dwelling, insect-eating creatures about 65 MYA
- shared characteristics: opposable thumbs, sensitive hands/fingers and toes with flat nails, no claws, close set eyes with binocular vision, large brain
prosimians
- lorises, pottos, lemurs (Lorids)
- omnivorous, Madagascar/S. Asia/Africa
- Tarsiers: tree-dwelling carnivores
- SE Asia, nocturnal, insectivores
simians
- new world –> arboreal with prehensile tail used for swinging
- old world –> some arboreal without prehensile tail, some ground dwelling
hominids - locomotion
- free swinging, running with large hands/long arms
- bipedalism in humans
- shorter arms, longer/stronger legs, foot bones form support, pelvis supports body, vertebrae adds flexibility in lower back, foramen magnum tucked under skull
hominids - feeding/diet
- skull ridge, size/shape of skull useful
- sagittal crest as point of attachment for jaw muscles
- molars grind, crush, mash food
- size of the jaw bones/protrusion, tooth row curvature
Australopiths
- foremen magnum positioned downward –> upright walking
Paranthropus
- large teeth, protruding jaws, skull with sagittal crest
Homo
- associated with stone tools
- larger bodies/brains
- smaller teeth, lighter/less protruding jaw/larger skull/brain case
- lighter brow ridges
evolution of humankind through natural selection
- likely spurred by environmental changes
- upright bipedalism –> advantageous in new habitat
- selection pressure i.e. skin pigment
ecology
interactions between organisms & the environment (biotic factors + abiotic factors)
environmentalism
advocacy of preservation, restoration, or improvement of the natural environment especially in relation to pollution
pollution
contamination of soil, water, or the atmosphere by the discharge of harmful substances
population ecology
study of how populations interact with the environment
- explore how factors influence age, size, density, growth rate of population
habitat
physical location where population members normally live
density
the number of individuals of a species per unit area or volume of a habitat
- varies among species
- usually estimated by sampling
population growth
population births - population deaths
population growth rate
change in population size per unit
birth rate
how many new organisms are added to the population each year
death rate
how many organisms leave/die in the population
life table
probability of surviving to a certain age
- table creates survivorship curve
Type I
- usually seen with humans and other large vertebrates
- low mortality rate
Type II
- many birds and some mammals
- age dependent mortality –> in the middle
Type III
- fish, invertebrates, plants
- high mortality rate
exponential population growth
- number of individuals added increases in proportion to population size
- J-shaped curve
logistic population growth
- population growth slows & levels off as resources become limited
- S-shaped curve
carrying capacity
- limit of individuals that a habitat can maintain or accommodate
- growth rate declines as carrying capacity reached
- depends on species/habitat/resources
density-dependent factors
- those that intensify as population density increases
- individuals compete for resources
- disease prevalence or predation may increase
- typically have more of an effect before independent factors
density-independent factors
- those unrelated to population density
- seasonal freezing, fire, floods, storms, environmental changes etc.
life history
organisms strategy for reproduction and survival
- age of first reproduction
- number/size of offspring
- energy cost of reproduction
- parental responsibility
opportunistic species
- tend to be short lived, reproduce at early age, many offspring that receive little care
- population growth rate may be high under optimal conditions
- Type III survivorship curve
- plants, many insects
equilibrium species
- long lives, mature later, extended parental care
- high probability of surviving
- mammals, some birds, some insects
- Type I & Type II survivorship curves
age structure
diagrams that help predict trends in growth
habitat
physical space with specific characteristics where organisms live
niche
all the resources required for survival growth & reproduction
climate
- sunlight/sunlight intensity
- light & temperature variation in precipitation via air conduction patterns
tilt
relative to the sun, leads to seasonal temperature changes
- Earth: 23.5 degree tilt
convection cells
warm and cool air cycle
- air first cools, cause water to condense and fall –> rain
biodiversity
We are losing biodiversity through scarce and polluted resources, and a changing climate.
Two major biomes
Terrestrial, aquatic
Primary Producers (terrestrial)
Plants primary producers (determined by climate)
primary producers (aquatic)
phytoplankton are primary producers (determined by physical conditions)
distribution of biomes
depends largely on precipitation and temperature
Polar Ice
temp is cold, dry and windy, phytoplankton in ice and ocean water are primary producers.
Tundra
very cold, dry; subsoil permanently frozen (permafrost); small plants with shallow roots; animals with thick fur; 20% of land surface; less animal diversity in Southern H. than Northern H.
Taiga
cold and abundantly dry, abundant coniferous trees; some mammals and birds stay year round.
Temperate rain forest
mild winters, cool summers, abundant rain, large conifers, amphibians, mammals, and fish.
Temperate deciduous forest
warm summers, cold winters, consistent rainfall, trees and migratory animals are common, lots of trees.
Temperate grassland
hot summers, cold winters, moderately moist, summertime drought, fires, grazing prevent tree growth.
Mediterranean shrub land (chaparral)
hot, dry summers, cool, moist winters, fire and drought resistant plants thrive here.
Desert
always dry; may be cool or hot, plants store water, and most animals come out at night time.
Tropical rainforest
warm and wet, highest species diversity of all the biomes, lots of herbivores and predators.
Aquatic biomes
occupy largest part of the biosphere, roughly 75% of earth’s surface.
Determined by salinity
Freshwater Biome
Standing bodies of water
cover less than 1% of the earth, contain .01% of all earth’s water supply,
- standing bodies of water: ponds, lakes, rivers, groundwater
- phytoplankton producers
- zooplankton consumers
- bacteria common in deep waters
- water depth/distance from shore determine distribution of biota
Freshwater Biome
flowing bodies of water
support different kinds of life, vary in character from source to downstream
- lakes, rivers, streams
- cold, clear, low in nutrients, swift
- Downstream water collects to create ponds
- consumers use smell rather than eyesight
Marine biome
3% is salt concentration, 97% of earth’s water. Source of most rainfall on earth, home to most life on the planet, photosynthesis by marine algae, source of the biosphere’s oxygen.
Intertidal zone
submerged or exposed ocean meets land, conditions vary with tide.
Coral reefs
occur in photic zone of warm tropical waters, algae primary producers, support diverse animal life, being destroyed.
Estuaries
freshwater meets ocean water
- salinity ranges depending on tide, usually bordered by mud flats
- biologically productive environment on earth, high in nutrients.
- threats: pollution, altered freshwater inflow, non-native species.
Competition
-/- Two or more species try to obtain the same limited resources: shelter, food, water, light, nutrients
Competitive exclusion principal
two species cannot coexist indefinitely in the same niche, one species wins. Exclusion not inevitable, species can agree to resource partitioning
Resource partitioning
resources used in a different way or at a different time
symbiosis
one species lives in or on another species (mutualism, commensalism, parasitism)
Mutualism
+/+ benefits both species, improves reproduction
Commensalism
+/0 one species benefits while the other species is unaffected
Parasitism
-/+ one species benefits at the expense of another
Predation
some species eat other species for energy and carbon
herbivores
eat plants for energy and carbon
adaptations
feeding on other organisms has negative effects on fitness. plants have adaptations such as: thorns, sap, distasteful, or poisonous
animals: camouflage, coloration, mimicry.
coevolution between species
adaptation in one species select for adaptation in another, species evolve in response to another
keystone species
predators that help save one species by eating the predatory species of that species
species richness
total # of species in a habitat
species evenness
the proportion of a community that each species occupies
ecological succession
process of gradual change in a community
Primary succession
occurs in an area where no life previously existed
Secondary succession
is caused by disturbances that disrupt biological communities
-disturbances destroy organisms, alter resource availability
pioneer species
first to colonize, determines other species
-rapid reproduction, efficient dispersal
Climax community
small-scale disturbances create patchy distribution of succession across a landscapr
Ecosystem processes
- energy flow through an ecosystem
2. chemical cycling between abiotic and biotic
food chains/ webs
a series of organisms that successively eat one another.
many energy and nutrient transfers
trophic level
position of an organisms in a food chain relative to energy source
producers-primary consumers-secondary consumers-tertiary consumers then all the waste= detritus and the decomposers eat that then break it down and the cycle starts again.
sunlight
tiny fraction converted to chemical energy. most absorbed, scattered, reflected by earth’s atmosphere or surface
producers
algae, plants: fix energy as it enters an ecosystem (gross primary productivity).
used for building biomass and reproduction
net productivity
gross primary productivity- heat= net primary productivity.
heat is lost
productivity (terrestrial)
depends on water availability and temperature
productivity (aquatic)
depends on nutrient availability
10% rule
one tenth of the energy at one trophic level is available in the next trophic level.
at every conversion heat is lost
consumers
inefficiently get energy from what producers fix.
-energy pyramid
-10% rule varies- more like 2%-30%
-depends on digestibility and metabolic rate
corn(100kal)-cow(10kal)-human(1kal)
biomagnification
chemicals in biomass at a low level can be more concentrated at higher levels.
DDT
pesticide used to kill lice and mosquitos in the 1960’s.
fat soluble
chemicals that are more likely to become concentrated.
biochemical cycling
recycling of elements between biotic and abiotic components.
four major reservoirs
Atmosphere, water, organisms, rocks/soil.
an element may combine with other elements.
some cycling relies only on geologic processes, bypassing the biotic (water cycle).
water cycle
producers/ consumers take up water from lake, river, pond, groundwater; they lose water by cellular respiration.
evaporation-atmosphere-rains down
carbon
element critical to life
carbon cycle
atmospheric CO2-photosynthesis converts CO2 to glucose- producers fix CO2-consumers eat-organic matter in soil broken down by decomposers- respiration returns CO2 to atmosphere.
atmosphere+oceans= slow cycle
rocks and soil+atmosphere=fast cycle
water CO2
dissolves in ocean- photosynthesis-aquatic food chain-respiration-back to atmosphere
Nitrogen
essential element, needed for creation of amino acids. 18% of atmosphere
nitrogen cycle
nitrogen fixation-bacteria and archaea fix to NH4. nitrates produce lightning
denitrifcation
convert NO3- NO2 happens in oxygen poor environments. Combustion happens through industry
phosphorus cycle
erosion (abiotic) releases phosphorus from rocks and sediments- decomposition returns it.
phosphorus dissolved-sedimentations-ocean sediments
too much applied causes pollution
phosphorus
needed for nucleotides, released by weathering
biodiversity
- Variety of ecosystems
- variety of species within a community
- Variety within the genes of each species
diversity
loss of diversity limits potential new discoveries
endangered
immediate high extinction risk
vulnerable
likely to become extinct soon
extinction
losing a species, today 200 of 20,000 gone extinct. 20% freshwater fish gone extinct.
Mountain ranges
air is cooler at highest elevation.
block wind and moist air masses on upwind scale.
