Biology 2 Exam 2

Niche

job role, function that an organism takes in an environment

Extinction

animals will change to fit empty roles

Mass extinctions cause

mass change in behavior

R-selective

* many young
* very little parental care
* generalists tendency
* ex: weeds

R-selective are

more likely to survive a mass extinction

K-selective

* few young
* more parental care
* more specific

Ecological selection after a mass extinction

1st colonization→ R selective → K selective

Adaptive radiation

opens niches; adapt/occupy them

* often with founders affect; need for niche fulfillment

Nicholas Steno

* older fossils are simple at the bottom


* younger fossils are complex at the top

Radio isotopes

* undergo radioactive decay
* addition of neutrons

1/2 life

lose 1/2 of radioactivity

Continental Drift

the plates experience rifts and divergence

* plates float on a liquid mantle

During the continental drift there is a

redistribution of air/water flow, temperature, and humidity

Coreolis Effect

* result of spinning
* everything spins on the equator

Precambrian Era

* pro-karyote→ eukaryotes → colony, specialized tissue

Eukaryotes

* nucleated cells
* much bigger

Cyanobacteria

no O2 → higher O2

* photosynthetic bacteria (nutrients from light)
* planet needed to be oxidized for free oxygen
* oxygen was toxic; makes toxic by-products

O2 radical (O2.-)

picks up an extra electron and wants to give it away

* bounce around; creates mutation

Anti-O2 radical (O2.-)

make ATP

* neutralizes oxygen; detoxifies it
* provides the energy to get big

Paleozoic Era Cambrian Period

* all animal phyla increased
* more phyla than present day due to mass extinction

Photosynthetic eukaryotes

* can occur because O2 levels are high and O3 zones are accumulated

O3 (ozone)

protects from UV rays

Paleozoic Era Ordovician Period

marine diversity

* mass extinction (lost 75%)
* result of glacierization (decrease of sea level)
* Volcanic activity
* air→ particulates to the sulfur
* reflects heat away

Paleozoic Era Silurian Period

* H2O jawless fish→ jawed fish


* colonization → land
* nonvascular plants → vascular plants
* enough O3 (arthropods and insects appear)

Paleozoic Era Devonian Period

* larger insects
* more insects
* some animals
* fish→ amphibians (vertebrates with lobed fins)
* 75% extinction
* meteorite hit

Paleozoic Era Carboniferous Period

* coal deposits
* ferns dominated (large forests, humid/swampy environment")
* big amphibians→ reptiles
* cooling at the end

Paleozoic Era Permian Period

* reptile diversity
* 95% of planet goes extinct
* 50% more oxygen here than present day
* Permian burp

Permian Burp

* more gas pressure than water lid pressure
* the bottom rotting organic matter gas escapes the water
* CH2 and CO2
* organic snow: everything above that dies; decays and flaked in water

Mesozoic Era Triassic Period

* lots of room for niche filling
* develop early dinosaurs (better at adaptive radiation)
* occupy empty niches
* first mammals occur/ some flowering plants (not many)
* conifer plants dominated (gymnosperms- evergreens)
* herbivore dinosaurs ate

Mesozoic Era Jurassic Period

* dinosaurs increased diversity
* fish also went through major diversity stage
* continents split, opened up more fish niches

Mesozoic Era Cretaceous Period

* super advanced dinosaurs
* sophistication (modifications)
* increase flowering plants (angiosperms)
* changes diet for dinosaurs
* mammals presence is greater
* diversify a little more
* Yucatan Meteorite Strikes

Yucatan Meteorite Strike

* 75% mass extinction

Cenozoic Era Tertiary Period

* any dinosaurs that survived the strike became birds
* mammals made it through
* occupy niches left
* flowering plants make it
* begin to diversify
* insect diversify increases due to pollination

Cenozoic Era Quaternary Period

* glaciation events (numerous)
* large mammals start to go extinct
* hominids → Homo sapiens
* frees up hands (easy manipulation) HUGE SPECIATION EVENT

Animals are

* multicellular; not a colony
* cells have a relationship (organization)
* tissues
* heterotrophs
* food from a source and break it down
* homeostasis= constant internal environment
* most animals have motion
* particular developmental patterns
* specific way an animals grows

2 embryonic tissues

* diploblastic
* ectoderm
* endoderm

3 embryonic tissues

* triploblastic
* ectoderm
* mesoderm
* endoderm

Ectoderm

* epidermis and nervous system
* outside layer

Mesoderm

* muscle, bone, cardiovascular system, kidney, renal system

Endoderm

* form GI tract, form respiratory system, and glands

Layer formation

* zygote→ morula→ blastocyst

Morula

solid mass

Blastocyst

* cells are undifferentiated
* gastrulation
* pushing your hand into a beachball (invaginate)
* protostome: mouth first
* deuterostome: anus first

Symmetry

* radial
* bilateral
* cephalization: sensory information and processor on one end
* have a brain

Acoelomate

solid mesoderm

Pseudocoelomate

one sided mesoderm

Coelomate

split mesoderm

Heterotrophs

* filter feeders: trap food from air or water
* sponge: sessile (settled in one spot)
* whale (not sessile): baleen (modified teeth)

Herbivores

* plant eaters→ cellulose
* animals don’t break down cellulose


1. must break down cellulose
* multi chambered sweatpants
2. eat lots of plants (abundance)
3. eat w/o killing the plant
* eat strategically so the plant can grow back

Predators

* kill and eat something else
* have morphology to capture and kill prey
* DANGER: animals fight back

Parasite

* harm to host (can modify behaviors)
* must evade host immune system (self vs. non self cell)
* Reproduction
* hermaphrodite: male + female
* produce lots of offspring
* lay lots of eggs

Endoparasite

inside the host

* ascaris (flatworm): crawl into parts of the body

Ectoparasite

outside the host

* leech, flea

Intermediate hosts

* host juvenile form of parasite
* not the final stage for the parasite

Detritovore

* aid in decay and breaking down of matter
* get rid of dead and decaying matter
* ex. earthworms

Diploblasts (2 layers; endoderm and ectoderm)

* 3 phyla


1. Porifera: sponges
2. Placozoa: found in deepwater trenches
* have an endoderm and an ectoderm
* also have fused cells (multi-nucleated)
3. Cnidaria: jellys, corals, sea anemones

Phyla Porifera

* sponges and they are diploblastic (edo and ecto derm)
* not colonial, have distinct tissues
* can be broken apart, find each other again: reassemble
* Simplest sponge
* sessile
* filter feeder (have pores)
* choanocytes (endoderm)
* pull water in (gastrovascular cavity)
* filter feed
* ostium (mouth)

Amoeboid cells

* undifferentiated
* distribute food
* change into another cell
* turn into gametes (sexual reproduction)
* bud (asexual)- good living conditions

Spicule

some are calcium/ some are silicon (glass)

* can break skin

Phyla Cnidaria

* 2 way gastrovascular cavities
* Cnidocytes (cell)
* stinging cells
* Nematocyst
* will burst if triggered (touched, chemicals)
* sends out sticky/barbed filament
* releases a toxin
* Medula and Polyp stage

Cnidaria life cycle

polyp stage→ colony bud→ medusa stage →planula

Phyla Cnidaria- Class Scyphozoa

sperm and egg→ planula→ polyp (bud and strobula)→ medusa (ephrya)→ adult jellyfish

* have to be able to coordinate
* have a neural network/ nerve net
* can be photosensitive
* ocelli: eyespots (light for dark)
* move towards or away from light

Class hydrozoa

* polyp dominant
* have a medusa stage for reproduction
* budding medusa→ planula→ polyp
* gastrozoid: catch food
* have tentacles to trap and pull into GVC
* gonadozoid/gonozad: reproduce (budding medusa)

Class anthozoa (sea anemones and coral)

* all coral, no real medusa stage
* sea anemones
* tentacles
* Acontia: internal tentacles that have stinging cells to kill food if it is not dead in the GVC
* Coral
* calcium carbonate base
* symbiotic relationship with algae (zooxanthella)
* dies when bleached

Phyla Placozoa

* found in deepwater trenches
* links porifera and cnidarians
* flat-worm like
* planula
* Have an:
* ectoderm: flagellated
* syncytium
* endoderm: glandular cells (have vesicles)

Syncytium

* one large cell with lots of nucleotides; multinuclear large cell (slime mold)
* causes question as to whether or not a placozoa is diploblastic

Triploblasts

* ectoderm, mesoderm, endoderm
* Protostomes or deuterostomes

Protostomes

* form mouth first
* Lophotrochozoans
* skeleton grows by adding to it
* Ecydozoans
* molting exoskeleton (made of chitin)

Deuterostomes

* form anus first

Phyla Platyhelminthes

* acoelomates (absent body cavity)
* solid mesoderm (depends on gas exchange)
* brains are a cluster of ganglia
* ladder-like nerve networks
* eyespots= ocelli
* chemoreceptors
* flame cells

Platyhelminthes are flat

so they can handle simple diffusion

Brain in Platyhelminthes

* brain: cluster of ganglia
* nerves; not a true brain
* on one end of the body; cephalization
* ladder-like nerve network
* 2 spinal nerves coming down
* communicating nerves
* eyespots are ocelli
* chemoreceptors: special sensory around the brain

Platyhelminthes shape and function

* flat so they can handle simple diffusion
* flame cells: get rid of waste
* filter everything; put back what they need
* beginning of a kidney
* typically hermaphrodites
* testis and ovaries in one worm

Phyla Platyhelminthes Class Turbellarian

* free living flatworms (planaria)

Phyla Platyhelminthes Class Trematoda

* flukeworms (parasitic)
* ectoparasites
* endoparasites
* suckers/hooks
* attach themselves to host
* egg hatches→ intermediate hosts (snail)
* Juvenile forms
* fish
* animals
* clams

Phyla Platyhelminthes Class Cestoda

* tapeworms
* No gastrovascular cavity
* live in GI tract
* take nutrients from the host

Mature proglottid

* male and female reproductive organs
* budding

Gravid proglottid

* breaks off
* contains fertilized eggs

Phylum Nematoda

* roundworms
* pseudocoelomate
* filled w/ fluid
* hydrostatic pressure
* pushes outward
* creates hydro skeleton
* ungulates to move and to move things through the GI
* 1 way gastrovascular cavity
* mesoderm is muscle
* cuticle is a
* protective layer
* rigid

Ascaris (Phylum Nematoda)

* male is hooked
* females are straight
* will look for the male hook to mate with if they are not hermaphrodites