insect exam 1

types of ecology

organismal, population, community, ecosystem, landscape, global

ootheca

protective protein structure around eggs → parental investment

ovoviviparous

hissing roach, give birth to live young

eusocial

live together in a colony, termites

Problems with fossil evidence

cannot get DNA, ancient fossils are rare

metazoa

multicellular animals

ecdysozoa

grow and shed skin to get bigger

onychophora

velvet worms, closest to arthropods without being arthropod

features of arthropods

tubular alimentary canal, open circulatory system, nervous system (two paired nerve cord along belly), excretion, respiration by gills or trachea, body is segmented, exoskeleton has chitin, paired segmented appendages

collembola

closest in category hexapod, extremely abundant in soil, external fertilization, internal mouthparts

insect inventions

external mouthpart, double-hinged mouthparts, flight (pterygota), folding wings, wings on inside (endopterygota),

last universal common ancestor

4 bya

first animals

1 bya

cambrian explosion

560 mya

first insects

440 mya

anthropocene

176 years ago

functions of exoskeleton

physical shape, structural support, points of attachment for muscles, protection from water loss, etc

SA:V ratio

insects have a large SA:V ratio, higher evaporation rate and more water loss

what is exoskeleton made of

mostly protein, different cuticle proteins with different proteins

extracellular matrix

what leads to strength of exoskeleton

helical arrangement of chitin

advantages of chitin

strong, lightweight, easy to make (sugar with nitrogens)

sclerotized exocuticle

mature cuticle, defines final size of insect, very hard

steps of molting

1. mature exoskeleton

2. seperates from epidermis

3. old cuticle digested

4. nutrients recycled

5. shed old cuticle

midgut

breaks food down

hindgut

saves or decides to excrete water

malpighian tubules

insect equivalent to kidneys

types of urine

ammonia - watersoluble must lose water to excrete it

uric acid is relatively insoluble - little water loss (nontoxic to insects) - can be excreted as dry whtie powder

apterygote insects

no true metamorphosis (mini-mes)

exopterygote insects

hemimetabolous (immature nymphs but look similiar to adults)

endopterygote insects

complete metamorphosis, egg, larva, pupa, adult,

imaginal disks

precursor for adult structures dividing in larval stages

ametabolous

no metamorphosis

what stays the same during metamorphosis

epidermal cells

ecdysone

makes the molt happen

Juvenile hormone

tells what type of molt it should have

PTTH

stimulates the prothoracic gland to secrete ecdysone

ecdysone + JH

larval to larval molt

tiny ecdysone peak+ NO JH

starts looking for a place to molt

ecdysone + Low JH

5th instar to pupal molt

ecdysone alone

pupal to adult molt

metheprene

JH analog, interferes witj molting

hydroprene

birth control for cockroaches

neem tree

azadirachtin, mimics ecdysone and interferes with molting and metamorphosis, smells and tastes horibile to insects

tsetse flies

have one larvae at a time (LARGE parental investment)

Wing Veins

Trachea, provide space where hemolymph flows

Direct muscles power flight

paleoptera, only can go up and down, one nerve impulse per contraction, slow, important for steering

Indirect flight muscles

neoptera, dorsal-ventral: pull top of body down and forces wings up, dorsal-longitudinal: scrunch and pulls wings down

how can you tell the more powerful muscles

number of mitochondria

asynchronous muscle

diptera and hymenoptera, sudden stretching triggers twitch, clicking mechanism of thoracic cuticle causes sudden movements to muscles in an alternating pattern

why can bees fly

non-steady state aerobics, air vortices produce lift and thrust, fast moving air has lass mass then slow moving air

what did insect wings evolved from

fusion of expanded flat parts of the legs nad extensions from the top of the body

hunt and capture predators

odonata and coleoptera

wait and ambush

neuroptera and mantodea

rotting vegetation

diptera

dead animals

coleoptera

waste of other organisms

coleoptera

mouth

external mouth made insects different from other hexapods, tell about food choices

insect head

made of 7 different segments

what is the proboscis made from

maxillae

thorax

foregut, 3 segments, legs and wings, smash up food, salivary glands

abdomen

11 segments, midgut and hindgut

midgut

small intestine equivalent, breaks down food and absorbs, malpighian tubules

hindgut

water and mineral homeostasis