Tree of Life Notes Flashcards
are Eukaryotes a member of the Archaea?
recent studies suggest that Eukaryotes are phylogenetically nested with in Archaea
if Eukaryotes are members of Archaea… what does this mean?
- Archaea are paraphyletic
- we are Archaea
prokaryote characteristics
- simple
- no nucleus
- no mitochondria
- small cell
Eukaryote characteristics
- complex
- nucleus
- mitochondria
- large
relative to prokaryotes, eukaryotes have …
- much larger cell sizes
- nucleus
- membrane-bound organelles
- DNA molecules associated with histones
- are commonly multicellular
- both has mitosis and meiosis
- complex cytoskeleton
how are Archaea and Bacteria different?
they differ in the details of their cellular structure, protein synthetic machinery
proteobacteria
- largest clade of bacteria
- endosymbiont that become the mitochondria in eukaryotes
examples of proteobacteria
- E.coli
- bubonic plague
- cholera
- salmonella
other names for cyanobacteria
blue-green algae
photosynthetic cyanobacteria
first organism to release O2 into the Earth’s atmosphere
ancestral cyanobacteria
the endosymbiont that became the 1st chloroplast
Plantae includes …
- glaucophytes
- red algae
- green algae
- land plants
common ancestor of Plantae
- MRCA
- had an endosymbiotic relationship with a cyanobacterium, which evolved into a chloroplast
red algae color
color obtained from pigment in chloroplasts, which have chlorophyll a
red algae
- mostly marine, few freshwater species
- sushi seaweed is red algae
phycology
scientific study of algae
green plants
- a clade that includes land plants, but also several clades of green algae
green algae
- paraphyletic
- diverse
- marine & freshwater
green algae reticulation in the tree of life
some fungi form symbiotic association with green algae to form lichens
examples of land plants
- ferns
- mosses
- conifers
- flowering plants
where and when did land plants first appear
- terrestrial environment
- 450-500 mya
adaptions required to live on land to reduce risks like:
- drying up
- greatly increased influence of gravity
- nutrient transport
waxy cuticle on leaves synapomorphy
prevents desiccation
stomata synapomorphy
- on the surface of leaves
- important in gas exchange and photosynthesis
mosses
non vascular/paraphyletic group including mosses, liverworts, and hornworts
moss reproduction
- reproduce using spores, not seeds
- depends on water to move sperm to eggs
effect of mosses lacking complex vascular system
- they cannot transport water and minerals from soil
- this causes them to be short
vascular plants
- includes ferns, gymnosperms, and angiosperms
- have a vascular system
vascular system of vascular plants
- includes the xylem and the phloem
- xylem conducts water and minerals from the soil
- lignin in the cell wall of the xylem increase structural support
- the phloem conducts the products of photosynthesis from the leaves
advantages of the vascular system in plants
- grow larger
- colonize new terrestrial environments
- diversify to new niches
key innovations
adaptations with such dramatic results
ferns
- have spores and a good vascular system
- alternation of generation
fern alternation of generations
- large plant: sporophyte
- small plant: gametophyte
gymnosperms
- includes ginko and conifers
- seeds but no flowers
conifer reproduction
- conifers have cones
- female cone contains seed
- male cone contains pollen
- pollen is transferred by wind
angiosperms
- flowering plants (flowers synapomorphy)
angiosperms pollination
- flowers improve pollination success due to animals an insects
- fruits aid in seed dispersal from animals, wind, or water
examples of stramenopiles
- diatoms
- brown algae
- oomycetes
stramenopiles
- diatoms deposit silica in their cell walls, creating intricate patterns
- radial or bilateral symmetry
- unicellular
brown algae
- color comes from carotenoids in their chloroplasts
- can be big
- most brown algae attach to rocks using holdfasts (not roots)
secondary endosymbiosis
chloroplasts evolved via endosymbiosis with red algae
examples of ophisthokonts
- fungi
- animals
ophisthokonts synapomorphy
a flagellum that is located in the posterior portion of the organism
fungi digestion
- digest food outside their body then absorb nutrients
- heterotrophs
- mechanism called absorptive heterotrophy
fungi synapomorphy
chitin in the cell walls
fungi and trees symbiotic relationship
fungi help trees absorb water and nutrients in return for organic compounds
lichens coverage
7% of the earths surface
lichen evolution
- form a symbiotic relationship with photosynthetic partners, such as green algae or cyanobacteria
other name for animals
metazoans
general characteristics of animals
- multicellular
- heterotrophic
- motility
animal synapomorphies
most are cellular details or molecular evidence
MRCA
most recent common ancestor
MRCA of animals
probably unicellular and looked a bit like chanoflagellates
sponges
- made up of cells called choanocytes, assembled into an organism
- filter feeders
examples of cnidarians
- jellyfish
- sea anemones
- corals
cnidarian charactersitics
- two embryonic cells: diploblastic
- one opening into the gut serves as mouth and anus
- carnivorous
carnivorous cnidarians
use specialized cells with harpoon like structures called nematocysts to capture prey
nematocysts
tentacles contain a trigger at the end of a coiled threat in the nematocysts. The trigger releases the threat and enters the prey
bilaterians
- group of animals with bilateral symmetry as embryos
- have a head & tail, as well as a back & belly
- triploblastic
- bilateral symmetry can be lost in adults
bilateral symmetry
left and right side mirror images of each other
blastopore
- during early development, in a phase called gastrulation, a hollow ball one cell layer think indents on itself
- blastopore is the indentation
where does the blastopore form in protosomes?
mouth
where does the blastopore form in deuterostomes?
anus
protosomes + deuterostomes
bilaterians
protosomes
- small marine predators of smaller marine organisms
lophophore
ring of tentacles around mouth
lophotrochozoans
derive their name from an ancestral feeding structure and type of larvae, but these traits have undergone a lot of evolution and not all taxa have them
ecdyzoans
have an outer layer called a cuticle that provides support and protection. It doesn’t grow, so it much be shed for organism to grow
examples of echinoderms
- sea stars
- sea urchins
- sea cucumbers
characteristics of echinoderms
- calcified external plates create their external skeleton
- water vascular system, including tube feet: important for gas exchange and locomotion
synapomorphies in chordates
- dorsal hollow nerve chord
- tail that extends beyond the anus
- dorsal support rod called the notochord
examples of Chondrichthyes
- sharks
- skates
- rays
characteristics of Chondrichthyes
- skeleton made of cartilage
- supportive structures in fins made out of keratin
actinopterygii
- ray finned fish which have rays of bones in fins
- very diverse
sarcopterygii
“lobe-limbed” vertebrates, in which the common ancestor has fleshy, lobed, paired fins joined to the body by a single bone homologous to our humerus
examples of sacropterygii
- coelacanths
- lung fish
- tetrapods
coelacanths
- thought to be extinct, but 2 species discovered
- important for understanding the evolution of the vertebrate limb
lungfish
- closely related to tetrapods than to coelacanths
- lungs in lungfish evolved from a gas-filled sac that extends from the esophagus in the common ancestor of bony fish
tetrapod
- 4 legged animals including amphibians, mammals, and reptiles
- limbs evolved from a lobe-finned ancestor
examples of amphibians
- frogs
- salamanders
amphibians
- moist skin with no scales
- eggs composed of a series of jelly-like layers, like fish eggs. eggs must remain moist
examples of amniotes
- mammals
- reptiles
- birds
- dinos
amniotes
- tough skin that is impermeable to water
- amniotic egg is relatively impermeable to water and allows embryo to develop in a contained aquatic environment
examples of reptilia
- turtles
- crocs
- snakes
- lizards
- dinos
- birds
characteristics of reptilia
diapsid skull, which includes 2 holes behind the eye socket
examples of squamates
snakes and lizards
squamates synapomorphies
- paired hemipenes
- details of teeth and skull
turtles
- dorsal and ventral bony plates form a shell
- dorsal plates are modified ribs
crocodylia
- carnivorous
- females build nests on land. female guards the nests and communicates vocally with her offspring
aves
- feathers are diagnostic
- vocalization and parental care
are dinos extinct?
no because we have birds
mammalia
diagnostic features include mammary glands and hair
three groups of mammals
- eutherians
- marsupials
- monotremes
eutherians
- placental mammals
- the placenta is a shared derived trait of the eutherian mammals
marsupials
carry their young in a pouch
monotremes
- includes platypus
- feature inclide egg laying and no nipples
great ape synapomorphies
- enlarged mammary glands
- knuckle walking
chimpanzees
- more closely related to humans than gorillas
- humans and chimps shared many similarities
