Midterm 2: plant structure and function (angio+gymno), fungi, ch 44 (animals), ch 24 (human evolution) Flashcards
4 main groups of land plants:
- bryophytes (mosses and liverworts)
- pteridophytes (ferns)
- gymnosperms (conifers)
- angiosperms (flowering plants)
what plants first acquired vascular tissue?
ferns
5 characteristics of monocots
- 1 cotyledon
- veins usually parallel
- vascular bundles usually complexly arranged
- fibrous root system
- floral parts usually in multiples of 3
5 characteristics of dicots
- 2 cotyledons
- veins usually netlike
- vascular bundles usually arranged in a ring
- taproots
- floral parts usually in multiples of 4 or 5
4 major events in the evolution of land plants
- bryophytes from algal ancestors
- vascular tissue in pteridophytes
- seeds/pollen in gymnosperms
- flowers in angiosperms
where does most photosynth occur in a plant?
the leaves
3 major tissues in leaves:
- epidermis
- mesophyll (Photosynth)
- veins (bulk transport)
what is the cost of acquiring CO2?
several hundred w molecs lost for every 1 CO2 molec acquired
stomata allow
CO2 to diffuse into the leaf
stomata are
hydrochemical valves
stomata make up what % of the leaf’s surface?
1-2%
how do the guard cells surrounding the stomata open?
inc the [] of solutes - req ATP
guard cells respond to (2)
- CO2 demand
2. w loss
what stimulates opening?
light
what stimulates closing (2)?
- high levels of CO2 inside the leaf
- dehydration
other leaf functions (4)
- protection
- climbing
- trapping
- attracting pollinators
xerophytes are
plants adapted to arid climates
trichomes
hairs; break up the flow of air
where does bulk transport occur?
btwn roots and leaves
phloem
outer vascular tissue that transports carbs from the leaves to the rest of the plant
xylem
inner vascular tissue that transports w and minerals from the roots to the leaves
two types of ground tissue
- pith
2. cortex
3 functions of ground tissue
- Photosynth
- storage
- support
xylem structure (3)
- dead, hollow conduit
- single or multiple cells stacked to form a hollow tube
- hydrogen bonds
phloem structure (3)
- living, simplified cells
- sieve plates with large pores
- carbs, amino acids, N, ions, hormones up and down
what are the 3 main nutrients taken up by roots?
N, P, K
mycorrhizae are
symbioses btwn roots and fungi
mycorrhizae (2)
- enhance nutrient uptake (P)
- fungi receive carbs
what elements limits agriculture?
N
what do N-fixing bacteria transform N gas into?
ammonium ions
what are roots used for (4)?
- adhering
- prop roots
- storage
- O acquisition
hormone means
“to excite”
hormones are
chem signals produced in 1 part of the body and trigger responses in target cells and tissues
tropism
growth toward or away from stimuli
what 2 tropisms do plants display?
- +ive phototropism
2. gravitropism
who did the tropism experiment?
Darwin and his son (1875)
what was the conclusion from the Darwin’s experiment?
that signals are transmitted from the tip downward (Auxin hormone)
what is 2ndary growth?
when the vascular cambium produces cells that differentiate on both its sides (rings in a tree)
where are 2ndary xylem located?
inside the vascular cambium
where are 2ndary phloem located?
outside the vascular cambium
what do wide growth rings indicate?
higher growth rates
what do narrow growth rings indicate?
slow growing
wood is
primary xylem
2ndary xylem (2)
- strength and stability
- transports w and nutrients from the roots to the leaves
what do fungi do?
decompose (cellulose and lignin)
how many species of fungi are known?
75,000
how many species of fungi worldwide?
5 mill
fungi are (2)
- euks
- multi
- heterotrophs
what are 4 ways fungi differ from plants?
- nutritional mode
- cell walls
- growth
- repro
who are the closest relatives to fungi?
animals
how do fungi acquire nutrients?
absorption
what do exoenzymes do?
digest food outside its body into simpler, absorbable compounds
hyphae
tiny filaments that make up fungi
mycelium
densely branched network of hyphae
chitin
a strong but flexible polysaccharide
septa
divide hyphae into cells
no septa in hyphae
continuous cytoplasmic mass w/ hundreds of nuclei
are fungi sexual or asexual?
both
are hyphae and spores usually haploid or diploid?
haploid
plasmogamy
occasionally 2 genetically different hyphae fuse
heterokaryon
mycelium w/ 2 genetically distinct nuclei
karyogamy
fusion of the haploid nuclei contributed by the 2 parents
when do fungi reproduce sexually?
if conditions deteriorate
is there a multicellular diploid stage in zygosporangia?
no
how many ascomycota species have been described?
over 60,000
ascus
a sac containing 8 spores formed during sexual repro
how many basidiomycota are there?
about 25,000
what types of fungi are in phylum basidiomycota?
mushrooms, shelf fungi, puffballs
basidium
club-like structure that produces sexual spores
mold
a rapidly growing, asexually reproducing fungus
yeasts
unicellular fungi that repro asexually by budding
lichens
mutualistic symbiosis of Photosynth microorganisns held in fungal hyphae
what are 2 photosynthetic partners in lichen associations?
green algae or cyanobacteria
where did most animal phyla arise?
Precambrian seas
how long ago did animals arise?
500-600mya
what geological site most accurately captures the Cambrian explosion?
Burgess Shale, BC
gastrula
a blind pouch formed during gastrulation which prod endo/ecto/mesoderms
are hox genes highly conserved?
yes
define highly conserved
moves through time relatively unchanged; high resistance to mutations
larval stages of animals are (4)
- sexually immature
- morphologically distinct
- diff foods and habitats
- undergo metamorphisis to attain adult morph
animals are/have/do (9)
- multi, heterotrophic euks
- ingestion
- no cell walls
- collagen
- nervous and muscle tissue
- sex
- gastrula
- hox genes
- larval stages
what are the 9 major animal phyla?
- chordata
- mollusca
- annelida
- arthropoeda
- Echinodermata
- porifera
- cnidaria
- platyhelminthes
- nematoda
chordata contains
mammals, reptiles, fish
mollusca contains
snails, clams
annelida contains
segmented worms
arthropoeda contains
insects/crustaceans
porifera contains
sponges
cnidaria contains
jellies
platyhemlinthes contains
flatworms
nematoda contains
roundworms
what is the animal clade’s common ancestor?
a colonial flagellated protist similar to modern choanoflagellates
what’s a hypothesis regarding animal evolution?
a colony of identical cells evolved into a hollow sphere; cells invaginated, creating a gut
how many animal phyla are there?
35
what is the old animal phylogeny based on?
morphology and embryology
what are 4 structural changes in the new tree?
- tissue
- symmetry
- body cavity
- development
parazoa lack
true tissue (sponges)
eumetazoan have
true tissue
what type of symmetry do animals in cnidaria have?
radial
cephalization is linked with bilateral symmetry. what is cephilization?
[] of sensory equipment at the anterior end
diploblastic means (3)
- 2 germ layers
- ectoderm develops into outer covering and the central nervous system
- endoderm lines developing digestive tube
are Radiata (cnidaria) diploblastic?
yes
are bilateria triploblastic?
yes
triploblastic means (2)
- mesoderm btwn ecto and endoderm
2. develops into muscles and many other organs
bilateria are further sectioned into having a body cavity or not. do platyhelminthes have a ceolem?
no
in terms of body cavities, nematoda are considered
pseudoceolomates
ceolomates have a true coelom, define true coelom
fluid-filled cavity completely lined by mesoderm
2 benefits to having a true coelom
- cushions internal organs
2. hydrostatic skeleton
what 3 phyla are protostomes?
mollusks, annelids, arthropods
what 2 phyla are deuterosomes?
echinoderms and chordates
what type of cleavage to protostomes undergo?
spiral, determinate
what type of cleavage do deuterostomes undergo?
radial, indeterminate
what does the blastopore in protostomes develop into?
mouth
what does the blastopore in deuterostomes develop into?
anus
what does it mean when you see a polytomy (flat line) on a tree?
don’t have the molec resolution to know what came 1st
the old and new tree are alike in 3 branchings: (but different on the rest)
- no tissues vs tissue
- radial vs bilateral
- protostomes vs deuterosomes
animals with pseudocoeloms or no coeloms at all are no longer considered more primitive they are thought to have
lost their coeloms
ecdysozoa (2)
- molt old exoskeleton and secrete a new, larger one (ecdysis)
- nematoda and arthropoda
how many extant species of animals are currently identified?
more than 1mill
what % of animals are vertebrates?
5%, u biased fucka
porifera (3)
- sessile
- lack nervous tissues
- suspension feeders
what lies inside the internal chambers of perforations in porifera?
flagellated choanocytes that trap food with their collars
how do sponges distribute nutrients across their cells?
amoebocytes
what forms spicules?
amoebocytes
what are hermaphrodites and what phylum is one?
prods both sperm + eggs; porifera
how many living species of cnidaria are there?
10,000
- mostly marine
4 examples of cnidaria
- hydras
- jellies
- ovemones
- corals
2 variations of cnidaria
- sessile polyp
2. floating medusa
medusas (eg. jellies) are mouth-down versions of what?
polyps
are cnidarians herbivores or carnivores?
carnivores
what are nematocysts?
organelles in cnidaria’s stinging tentacles that evert a poisonous, entangling thread
are hydras found in fresh or salt w?
fresh
how do hydras do sex?
- repro asexually via budding
- when env conditions deteriorate, they do sex (lesistant zygotes)
corals (4)
- are polyps
- are colonial
- secrete a hard exoskeleton of calcium carbonate
- build on the remains of earlier generations
sea anemonies are a mutualistic symbioses with
Photosynth dinoflagellates
lopotrochozoa
animals that do not perform ecdysis
why do platy’s have flat bodies?
diffusion
what are 2 parasitic platy’s?
flukes and tapeworms
trematode fluke Schistosoma infects 200 mill ppl and causes serious illness (3)
- anemia
- dysentery
- swimmers itch
what anchors a tapeworm in a digestive tract?
scolex (suckers and hooks)
proglottids
sacs of sex organs
how would you get a tapeworm outside of Canada?
undercooked meat
how would you get a tapeworm inside of Canada?
undercooked game
tapeworm/human lifecycle (5)
- proglottids leave in hosts feces
- eggs ingested by intermediary hosts, usually pigs or cattle
- larvae encyst in muscles
- humans eat undercooked meat contaminated with cycts
- mature in human
mollusca are (3)
- marine
- soft-bodied
- hard shell of CaCarbonate (some reduced, like octopi, slugs, squids)
3 features of mollusca’s body plan
- muscular foot
- visceral mass
- a mantle
what does the mantle do?
drapes over the visceral mass and secretes shell
how do mollusca eat?
scrape food using radula
molluska sex
- most are separate sexes,
- snails are hermaphrodites
what type of larva do marine mollusks have?
tropophore (same as annelids)
4 types of molluska
- chitons
- snails and slugs
- bivalves
- squid + octopuses
chitons are (2)
- marine
2. oval
how many dorsal plates are chitons shells divided into?
8
most snails and slugs are (2)
- marine
- protected by single, spiralled shells (if no shell, chem defenses)
during embryonic development, snails undergo torsion
visceral mass is rotated up to 180 deg
some species of snails/slugs are predators. how are their radula’s modified?
to bore holes in the shells of other orgs
what functions as a lung in terrestrial snails?
lining of the mantle cavity
4 examples of bivalves
- clams
- oysters
- mussels
- scallops
what are bivalve abductor muscles used for?
closing the shell to tightly protect the animal
bivalves are suspension feeders. track the path of w
enters via incurrent siphon, passes over gills, exits via excurrent siphon; traps fine particles in gill mucus and the cilia convey them to the mouth
squid/octopi have a well-developed nervous system (4)
- complex brain
- well-developed sense organs
- eyes similar to vertebrate eyes
- capable of learning
where do you find annelida’s?
freshw, damp soil, marine
3 types of annelida
segmented worms: polychaetes, leeches, earthworms
is the coelom of an annelida partitioned?
yes, by septa
annelidan digestive system consists of (4)
esophagus, crop, gizzard, intestine
do annelids have an open or closed circulatory system?
closed
metanephridia
excretory tubes that act like kidneys, found in each segment of an annelidan
annelids have cerebral ganglia. are they cephalized?
yes
earthworm sex
crossfertilizing hermaphrodites
polychaete locomotion
each segment has paddlelike parapodia
feather-duster polychaetes eating
trap plankton on feathery bristles
where do leeches live?
fresh w, some terrestrial
what do leeches secrete?
hirudin, an anticoagulant
where are nematoda found (4)?
- aquatic habitats
- wet soil
- plant tissue
- body fluids of animals
what do nematoda play a major role in?
decomposition
nematoda repro
sexual reproduction (up to 100,000 eggs per day)
do nematoda have a complete digestive tract?
yes
what do nematoda cause?
Trichinella Spiralis (undercooked meat)
how many arthropod species are there?
over 1 million (2/3 of species)
the success of arthropods is due to (3)
- body segmentation
- hard exoskeleton
- jointed appendages
what are arthropod exoskeletons made of?
protein and chitin
what’s one disadvantage of doing ecdysis?
left temporarily vulnerable when molting
what are 3 functions of an exoskeleton?
- protection
- locomotion
- prevents w loss on land
what are the 4 main evolutionary lineages of arthropods?
- Cheliceriformes
- Myriapoda
- Hexapoda
- Trilobita
what are 3 examples of a cheliceriform?
spiders, horseshoe crabs, scorpions
what are 2 examples of a myriapoda?
cent + milipedes
hexapoda
insects
2 examples of crustacea
- lobsters
- barnacles
trilobites died in what extinction?
Permian, 250 mya
living fossil
has not changed much from its ancestors (eg horseshoe crab)
how does gas exchange occur in spiders?
book lung with extensive SA
how many pairs of walking legs per segment do millipedes have?
2
how many pairs of walking legs per segment do centipedes have?
1
millipedes are (2)
- herbivores
- among the earliest land animals
centipedes are (2)
- carnivores
- have poison claws
insects inhabit (3)
terrestrial habitats, fresh w, air
how long do fossils date back for insects?
400mya
flight is key to the success of insects; it allows insects to (3)
- escape
- find food and mates
- disperse
metabolic wastes in insects are removed by
malpighian tubules (kidney)
what does the tracheal system in insects do?
carries O2 from spiracles directly to cells
do insects have brains?
yes; 2 ventral nerve chords fusing into a cerebral ganglion
incomplete metamorphisis
young resemble adults
complete metamorphisis
larval stages change morphology completely during pupal stage
what are 3 things insects use to mate sexually at the right time?
- colouration
- sound
- odour
spermatophores are
sperm packets deposited by the male
spermatophores can contain additional nutrients such as
nuptial gift (sometimes the male)
where do female insects lay their eggs?
on/in a larval food source
affect other terrestrial orgs in 3 ways
- pollination
- vectors for diseases (malaria, African sleeping sickness, west nile virus, plague)
- pesticides
crustaceans are mostly marine. what is one example of a terrestrial crustacean?
wood bug
are barnacles mollusks or crustaceans?
crustaceans
what are 5 types of crustaceans?
- lobsters
- crabs
- crayfish
- shrimp
- barnacles
where do echino’s live?
marine env’s only
what type of symmetry do echinoderms have?
pentaradial (metamorphosis from bilateral larva)
what are 3 functions of tube feet?
- locomotion
- feeding
- gas exchange
what is the w vascular system?
a network of hydraulic canals branching into extensions called tube feet
3 classes of echino’s that are of interest for us:
- sea stars
- sea urchins/sand dollars
- sea cuces
3 steps to sea stars eating bivalves
- pull apart shells with tube feet
- evert its stomach btwn the shells
- enzymes break down soft bivalve body
all chordata at some point in their life-time share (4)
- notochord
- dorsal hollow nerve chord
- pharyngeal slits
- muscular, post-anal tail
notochords are
cartilage-like flexible rod
notochords are present in
chordate embryos
notochords provide
skeletal support
the dorsal hollow nerve cord develops from the
ectoderm
the dorsal hollow nerve cord becomes
the central nervous system (brain + spinal cord)
pharyngeal gill slits are often modified for
suspension feeding or gas exchange
pharyngeal slits function to
connect the pharynx to outside + allow w to exit w/out entering the digestive tract
muscular tail ending location
posterior to anus
what does the muscular tail become in aquatic species?
a propulsive force
what are 2 representatives of urochordate?
- tunicates
2. sea squirts
cephalochordata
lancelets
vertebrata are characterized by (4)
- cranium
- pronounced sephalization
- vertebral column
- closed circulatory system
neural crest
a group of embryonic cells that contribute to the bones of the cranium
what are 2 examples of agnathans (jawless vertebrates)
hagfish and lamprey
how many species of hagfish are there?
30
what are hagfishes cranium and notochord made of?
cartilage
how many species of lamprey are there?
35
lampreys are
ectoparasites
when did jawed animals replace agnathans
360 mya
2 major breakthroughs of fish:
- jaws enable them to grip food firmly
2. paired fins enabled them to manouver accurately
chonrichthyes types (3)
sharks, rays, ratfish
what are chondrichthyes endoskeletons made of?
cartilage
how do chondrichthyes attain buoyancy?
oils in liver
what happens if a shark stops moving?
it dies
oviparous
encase eggs in a protective case and lay them externalls
ovaviviparous
retain fertilized eggs in oviduct; nourished by egg yolk; live birth
vivaparous
live births; nourished in uterus via placenta
what are the 3 classes boney fish can be split into?
ray-finned fish, lobe-finned fish, lungfish
what is the function of an operculum?
- protective flap
- draws w over gills
what type of boney fish may have given rise to tetrapods?
lobe-finned fish
what does it mean to aestirate?
warm weather hibernation
when did tetrapods move to land?
about 360mya
what 2 animal types are in class amphibia?
salamanders and frogs
define amphibian
2 lives - metamorphosis from aquatic tadpole to terrestrial adult
what are 3 ways amphibians retain close ties with w?
- moist skin carries out gas exchange
- eggs lack a shell and dehydrate in air
- most have external fertilization
who are in the amniotes clade?
- mammals
- birds
- reptiles
3 adaptations amniotes made for terrestrial living
- amniotic egg
- wproof skin
- ribs to ventilate lungs
what enables life cycles of amniotes to be entirely on land?
amniotic eggs (shell retains w)
what are 3 sections of “reptiles”?
lepidosaurs, archosaurs, turtles
what 2 animal types make up the lepidosaurs?
- lizards
2. snakes
what 3 animal types make up the archosaurs?
- crocodiles
- dinosaurs
- birds
ectotherm
absorb env heat
what is one advantage of being an ectotherm?
10% of calories req’d by mammal of equivalent size
endothermic
keep body w through metabolism
are birds endo or ectothermic?
endothermic
how are the sexes of turtles determined?
temp
are crocodiles hetero or homodont?
homo
what are 3 ways bird anatomy is modified to red. weight?
- 1 ovary
- toothless (gizzard)
- bones are honeycombed
how many chambers does a birds heart have?
4
what is the function of downy feathers?
trap air; insulation
contour feather function
aerodynamic shape
filoplume feather function (3)
- maintains the position of contour feathers during flight
- display
- tells how the contour feathers are angled
what did Archeopteryx have that made it resemble the modern bird (3)
- clawed forelimbs
- feathers
- tail w/ vertebrae
+ teeth
when did adaptive radiation for mammals occur and why?
65 mya when the dino’s died
what is the defining characteristic of class mammalia?
mammary glands + hair
name 4 types of teeth in mammals heterodont mouths
- incisors
- carnivores
- premolars
- molars
3 modern groupings of mammals
- monotremes
- marsupials
- eutherians
monotremes
egg-laying mammals
marsupials
pouched mammals
eutherians
well-developed placental stages
2 living examples of monotremes
- platypuses
2. echidna’s
3 types of marsupials in Canada
- possums
- kangaroos
- koalas
what are 7 adaptations primate made for arboreal life?
- hands/feet for grasping
- large brains
- short jaws
- flat nails, not claws
- parental care & complex social behaviour
- depth perception
- excellent hand-eye coordination
opposable thumbs found only in
anthropoid primates
who are in the prosimians?
lemurs, lorises, tarsiers
who are in the anthropoids?
monkeys, apes, humans
old world monkeys are both ground-dwelling and arboreal. what are new world monkeys?
just arboreal
5 types of apes
- gibbons
- orangs
- gorillas
- chimps
- bonobos
how long ago did apes diverge from old world monkeys?
25-30mya
gorillas and chimps are highly
social
only gibbons are orangs are
primarily arboreal
how many yrs of evo did huans and apes share?
3.5 bill yrs (except for the last 6 mill yrs)
how many species of primates?
approx. 400
3 physical traits unique to primates
- opposable thumbs
- eyes on the front of face
- nails instead of claws
what % diff in DNA sequence is there btwn humans and chimps?
1% (1 deg diff in denaturation temps)
how long ago were we tree dwellers?
30-35mya
20mya the climate became drier and the savanna habitat inc. what did this mean for the primates?
less arboreal life -> divergence
diverged from a common ancestor
approx. 5-7mya
4 big diffs btwn us and chimps:
- brain size triples over the past 6 mill yrs
- bipedal posture: hominoid ancestors walked on all 4 limbs
- jaw shape: ancestors had longer jaws than modern humans (+ changes in dentition)
- reduced size diff btwn sexes (suggests monogamy became more common)
where did hominids originate?
eastern and southern africa
what came first, bigger brain or bipedalism?
bipedalism
famous Australopithecus fossil
lucy; found in ethiopia
3 Australopithecus and us similarities
- bipedal
- human like hands and teeth
- chimp-sized brain
what did homo habilis have (2)?
- stone tools
2. larger brains
who was the first homo to migrate out of Africa?
homo erectus
where did homo erectus go once they left Africa?
Europe and asia
when was fire use dated to?
1mya
where did Neanderthals live?
Europe/middle east
2 diffs btwn humans and neanderthals
- larger brains
2. heavily built
did Neanderthals contnribute to the human gene pool?
yes
what are the 2 hypotheses for the origin of modern humans?
- multiregional hypothesis
2. out of Africa hypothesis
multiregional hypothesis
modern humans evolved from local pops of homo erectus (genetic similarity a product of interbreeding)
out of africa
homo sapiens evolved from a 2nd migration out of Africa which replaced all regional pops of homo’s
which hypothesis does the genetic data support?
out of africa
mitochondrial eve
mitochondrial DNA suggests a time of genetic divergence of 1 or 200,000yrs ago
why is mDNA good for analysis?
no crossing over
originally, Neanderthals were thought to be replaced, but now we think we
interbred (for Asians/Europeans)
y chromosomes are important for genetic data because they are passed from male to male w/out
crossing over of the x-chromosomes
researchers were able to infer divergence from common African ancestor
approx. 200,000yrs ago
what % of genetic variation in humans occurs within a pop?
85%
what % of genetic variation occurs btwn pops w/in races?
8%
what % of genetic variation occurs btwn races?
7%
where are the most diverse pops found?
Africa
