Biology 104 - Exam 2 Flashcards
Hadean eon
- surface temp. 500-1000 ℃
- volcanic eruptions, earthquakes, intense UV radiation
- bombardment by comets, meteorites, possible asteroids
- atmosphere: pressure & chemical composition very different
Extraterrestrial
- molecules of life arrived via meteorite
Supernatural
- not within realm of scientific inquiry
Miller & Urey
- replicated/simulated Earth’s atmosphere and conditioned and added energy
- condensation of liquid containing amino acids
- hypothesized: minerals of dry/hot surfaces (earth) catalyzed reactions
stromatolites
sediment and cynobacteria
- some oldest fossils resemble stromatolites
Prokaryotes
- 2 billion years –> lived/evolved alone
- found wherever life is found –> outnumber eukaryotes
- can cause disease, be beneficial, important for nutrient cycling, important to organisms
- bacteria and archaea
- reproduce by binary fission
nucleiod
where DNA resides
plasmids
circles of DNA apart from the chromosome
ribosomes
use mRNA to make proteins
cell wall
gives cell shape
- bacteria have peptidoglycan –> archaea do not
slime layer
sticky layer of proteins/polysaccharides that may surround cell wall
pili
protein allow adhering
flagella
whiplike extension that acts a propeller, allows cell to move
endospore
- dormant inner cell protected by thick coat
- can survive boiling, drying, disinfectants. UV radiation
- have to be superheated to kill
living organisms require ___, ___, ___
energy, carbon, liquid medium (body cells in water)
Classifying prokaryotes
inorganic = photo(light)autotroph/chemo(carbon)autotroph organic = photoheterotroph/chemoheterotroph
Bacteria
- majority of known prokaryotes
- form symbiosis with other organisms
- may cause disease
- many produce antibiotics
- found in food, food webs, break down organic matter
symbiosis
close association between organisms of two species that live together for mutual benefit
examples of bacteria
- actinomycete: soil bacteria => decomposition
- cyanobacteria: autotrophic, first to produce O2 via photosynthesis
- giant bacteria: visible to naked eye
archaea
- originally characterized as extremophiles
- also found in less extreme environments
- essential to geochemical cycles on land/ in water
examples of archaea
halophiles: slaty/saline environment
methanogens: methane gas produced as byproduct of anaerobic respiration
thermophiles: live in extremely hot environments
pathogenic
disease causing bacteria
nitrogen fixers
convert nitrogen from the atmosphere to available form of nitrogen (ammonia)
prokaryotic function
- many do work in human body
- good bacteria crowd out bad –> some essential to digestion
- harmful bacteria can be ingested/inhaled/enter body through wounds or orfices
- ecologically important –> essential decomposers
photosynthesis
light energy converted to chemical energy
light reactions
- convert solar energy to chemical energy
carbon reactions
uses chemical energy to make glucose from carbon dioxide
chloroplast
- light absorbing organelle
- most dense interior cells of plant leaves
- green color comes from chlorophyll
chlorophyll
a = dark green b = light green caratenoids = yellow
protons
particles of light absorbed by chlorophyll –> when electron excited, gives off energy when dropping to original state
water-splitting photosystem
replenishes electrons that get kicked out of chlorophyll
electron-carrying photosystem
NADPH carries electrons to carbon cycle
carbon cycle
input: 9 ATP, 6 NADPH, 3 CO2
output: 9 ADP + 9 P, 6 NADP+, 1 G3P
- need for glucose –> power cell respiration
- –> cellulose/starch are basis to build organism
eukaryotic cell
- nucleus
- other membrane-bound organelles –> i.e. mitochondria
evolution of endomembrane system
- hypothesized to be the infolding pf cell membrane
evolution of mitochondrion & chloroplasts
- endosymbiont theory
- mitochondria hypothesized to be aerobic bacteria –> chloroplast usually photosynthetic bacteria
endosymbiont theory
mitochondrion and chloroplasts originated as free-living prokaryotes
evidence - eukaryote evolution
- size, shape, structure similar between organelles and present bacteria
- analysis of DNA revealed similarities of bacterial DNA
multicellularity
- 1.2 BYA resulted in explosion of variety of forms/sizes
- evolved independently in several lineages —> might also be due to symbiosis
protist
eukaryote that is not plant, animal, or fungi –> many unicellular, many microscopic
algae
- any photosynthetic protist that lives in water
- unicellular/multicellular
- chloroplasts with pigment variety
- functionality: produce atmosphere O2
dinoflagellates
- cellulose with protective plates
- red tide –> population explosion, produce toxin
diatoms
- silica cell wall
- two cell walls fit together like shoe box
red algae
- many large, some microscopic
- occupy deeper water => shorter light wavelengths needed to survive
brown algae
- most complex and largest protists
- food/habitat for other life
green algae
- share many characteristics to plants
- unicellular, filamentous, colonial, multicellular
- ex. chlamydomonas, volvox, ulva
water molds
- decomposers/parasites of plants & animals
slime molds
- live in damp habitats
- single cells OR large masses acting like multicellular
- plasmodial –> bacteria/dead organic matter as food
protozoa
- “first animal”
- most unicellular/chemoheterotophs
- ingest/absorb energy & carbon
- aquatic –> free-living, some parasitic
- mostly asexual reproduction
ciliates
- unicellular, some parasitic/symbiotic
apicomplexans
- immobile, spore-forming internal parasites of animals
fungi
- eukaryotes
- most multicellular heterotrophs
- more related to animals than plants
- –> store excess glucose as glycogen, cll wall made of chitin
- live everywhere
- essential decomposers
hyphae
cytoplasm strands, interconnected, secrete enzymes
mycelium
mat that maximizes contact with organic matter
fungi - reproduction
- release spores produced sexually/asexually
- spores germinate into hyphae where there is moisture and food
- classified by structure
fungi - decomposers
- hyphae invasive, digest polymers
- air loaded with spores, colonize/initiate decomposition
- keep ecosystems stocked with inorganic nutrients for plant growth
mycorrhizae
fungi + plant root exchange nutrients –> nitrogen + phosphate (fungi) for sugar (plant)
lichens
fungi + algae, provide shelter in exchange for nutrients
fungi - parasites
- 30% fungi parasitic
- attack agricultural crops/plants
- cause human disease
plant
multicellular, photoautotrophic eukaryote
- evolved from aquatic ancestor
- use CO2, H2O, and light to form basis of life
origin - plants
- closely related to green algae
- ancestor thought to have lived in water habitat with periods of dryness –> natural selection favored those who could survive both
- terrestrial adaptation used today are basis for defining major groups
charophyceans
closest living plant relatives
land adaptation
- must acquire resources in different way
- new habitat requires support and material transport
- adaptations for reproduction in new drier environment
resources - plants
- light/CO2 aboveground
- water and minerals below ground
- avoid dehydration –> cuticle
- allow CO2 in –> stomata
- distant organs require support –> vascular tissue
alternation of generations
- gametophyte + sporophyte => each produces the other but in different ways
- gametes (n) => fertilization => zygote (2n) => mitosis => sporophyte (2n) => meiosis => spores (n) => mitosis => gametophyte (n) => mitosis => gametes (n)
- multicellular diploid sporophyte makes haploid cells by meiosis
- multicellular haploid gametophyte makes haploid gametes by mitosis
cuticle
waxy covering to keep plant from drying out
gametangium
protective jacket of cells surrounding moist chamber where egg is held
bryophytes
- individuals grow in spongy habitats
- not aquatic => require wet habitats to acquire nutrients from reproduction
- liverworts, hornwort, mosses
seedless vascular plants
- true roots & stems with lignin and leaves
- resources collected from different places, still need water to reproduce
- xylem (water) and phloem (sugar) tubes
- ferns
gymnosperms
- cone-bearing plants with exposed seeds
- appeared at end of carboniferous period > colder and dryer
- complete life cycle on dry land, withstand harsh cold
- pollen sacs produce microspores, female cones produce megaspores
angiosperms
- seed enclosed in ovary (fruit) –> facilitates dispersal
- flower facilitates sexual reproduction –> draw attention of animals
monocots
- one cotyledon
- usually parallel veins
- scattered vascular bundles
- floral parts in multiples of 3
- fibrous root system
eudicots
- two cotyledon
- branched veins
- vascular ring bundles
- multiples of 4/5
- taprous root system
angiosperm - reproduction
- 4 megaspores created, 1 survives
- 1 egg but polar nuclei
pollinaiton
pollen lands on stigma of flower –> pollen grain germinates into pollen tube
double fertilization
- fertilizes both egg and polar nuclei
- endosperm nucleus (3n) => triploid cell —> provides resources to growing embryo
animals
- eukaryotic, heterotrophic, obtains nutrients by ingestion and internal digestion
invertabrates
without a backbone
vertabrates
with a backbone
bilateral symmetry
if only one plane can divide an animal into mirror image
radial symmetry
if a plane through the body from mouth to opposite end creates multiple mirror images
cephalization
concentrated sensory organs and a brain in the organisms head
- seen with bilateral symmetry
germ layer
in animals with true tissues, groups of cells that interact and contribute to the formation of tissues and organs
2 germ layers
endoderm (in), ectoderm (out)
3 germ layers
endoderm (in), mesoderm (mid), ectoderm (out)
protostomes
mouth develops first
deuterostomes
anus develops first, mouth follows
coelom
body cavity
- tube within tube body design
- fluid filled –> cushions organs, permit growth and movement, separate from outer body wall
- forms completely within mesoderm
pseudoderm
- partly lined with mesoderm
- serves as hydrostatic skeleton
incomplete digestive tract
food is ingested and excreted from the same opening
complete digestive tract
mouth takes food in, anus expels waste
segmentation
- division of body into different parts
- flexibility & specialization of body
sponges
- multicellular, lacks true tissues
- phylum: porifera
- spicules: spines to repel predators
- filter feeders: cells specialized to move water, trap/digest food, distribute nutrients
- collar cells: cells lining inner sponge membrane with flagella
cnidarians
- multicellular, two layers of true tissues, radially symmetric, incomplete digestion, no segmentation, body wall is hydrostatic skeleton, specialized cells
- phylum: cnidaria
- reproduce sexually/asexually
- cnidocytes: stinging cells
- polyp form –> sessile, medusa form –> free-living
- carnivores
- gastrovascular cavity –> cells secrete enzymes for digestion
flatworms
- bilateral symmetry, protostomes, incomplete digestion, organ system, simple cephalization
- phylum: platyhelminthes
- simple bilateral symmetry –> no coelom
- some free-living/some parasitic
- flat body allows exchange of materials with environment
planarians
- free-living flatworms
- hermaphroditic
- secrete mucus for protection
parasitic
- tapeworms –> live in host (suckers and hooks)
- blood flukes –> intermediate host (snails)
Mollusks
- organ system, bilateral symmetry, usual cephalization/simple brain, hydrostatic skeleton, sexual reproduction, complete digestive tract, soft bodied, unsegmented, most protected by hard shell, no segmentation
gastropoda
single, spiral shaped shell –> snail
bivalves
shell of two halves –> scallop, clam
cephalopoda
shell, no shell, reduced shell –> octopus, squid
mantle
layer of specialized tissue, covers visceral mass
radula
raspy mouthpart used to scrape/tear up food
foot
movement (gastropods, cephalopods), attachment/digging
annelids
- organ system, bilateral, cephalization, true coelom, complete digestion, repeating segments
- phylum: annelida
- terrestrial, freshwater, marine
- oligochaete –> hermaphroditic (earthworms/leeches)
- polychaete –> separate sexes
clitellum
site of fertilization
oligochaete
- earthworms/leeches
- leeches –> strong jaws, saliva contains anesthetic and anticoagulant
polychaete
- crawl/burrow in sea floor, use hard bristles for movement
- segments used for respiration
roundworms
- organ system, bilateral, cephalization, pseudocoelom, complete digestion, no segmentation, molting (cuticle)
- phylum: nematoda
- aquatic, wet terrestrial habitats
- free-living –> decomposers
- parasitic –> live in fluids/tissues of host
arthropods
- most abundant/diverse in animal kingdom
- phylum: arthropoda
- segmented animals with jointed appendages, exoskeleton, molting –> segments have specialized functions
exoskeleton
- made of chitin & proteins –> flexible but tough
- protection and points for muscle attachment
must be shed for growth –> molting
5 subphylla of arthropods
- trilobites (extinct)
- chelicerates - horseshoe crabs, spiders, scorpians, mites, ticks
- crustaceans
- millipedes/centipedes (myriapoda)
- insects
