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bcor exam 4

Terms in this set (44)

Fungi get nutrients by absorption. How does that affect their morphology?
- Fungi secrete enzymes so that digestion takes place outside their cells
- Morphology must have a large surface area, body of fungus = mycelium (bundle of hyphae - long string of single cells)
What is a lichen?
A fungus (gains sugars) in a symbiotic relationship with algae (gains nutrients)

Not a clade, but a growth-form (like "trees")
What are mycorrhizae?
a symbiotic relationship between a fungus (gains sugars) and a plant (gains nutrients)
How is the general fungal life cycle similar and different to plant life cycles?
Similarities = produces spores, alternation of generations

Differences = has both a sexual and asexual life cycle, sexual involves plasmogamy (N, fusion of cytoplasm) -> heterokaryotic intermediate stage (dikaryotic cell with 2 nuclei) -> karyogamy (2N, fusion of nuclei)
Be familiar with two of the groups of fungi
sac fungi (ascomycetes) = yeast, truffles, Penicillium -> spores develop in sacs

club/gill fungi (basidiomycetes) = shiitake, most "mushrooms" -> have gilled caps
When did animals first evolve? What protists are they related to? How do we know?
- Evolved around 600mya
- Sister group = choanoflagellates (single celled eukaryotes)
- 1st animal = sponges, have cells that resemble choanoflagellates
What are some of the defining characteristics of "animals"?
- Multicellular
- heterotrophic
- internal digestion
- mobile
protostome vs deuterostome
Protostome - mouth develops first from blastopore

Deuterostome - anus develops first from blastopore
radial vs bilateral symmetry
Radial - symmetric in all directions

Bilateral - symmetric in one direction
What are the three basic tissue systems? What is a coelom?
Endoderm - digestive tract
Mesoderm - muscles/tissues
Ectoderm - outer body covering
Coelom - body cavity
major clades of animals (Eumetazoa, Bilateria, Deuterostomes, Lophotrochozoa, Ecdysozoa
- Metazoa (sponges) - no tissues
- Eumetazoa (jellyfish, coral, anemones) - true animals with tissues (muscles, nervous system)
- Bilateria (all else) - bilateral symmetry
- Deuterostomes (sea stars,chordates) - anus develops first
- Lophotrochozoa (mollusks & earthworms) - distinctive larvae stage
- Ecdysozoa (arthropods, nematodes) - shedding and molting of exoskeleton
Porifera
ex: sponges
- clade = Metazoa
- no true tissues/head/mouth/heart
- no set symmetry
- do not move
- filter-feed through pores
- reproduce asexual (budding) or sexual (release sperm cloud in water)
Cnidaria
ex: jellyfish, corals, anemones
- clade = Eumetazoa
- has tissues/muscles/nervous system
- no head
- radial symmetry
- eat via one opening (both mouth/anus)
- swims with muscles
- asexual repro = polyp (rooted) & sexual repro = medusa (floating)
Mollusca
ex: clams, snails, octopus, squids
- clade = Lophotrochozoa
- have a muscular foot or tentacles
- a head
- mantle/shell
- toothed tongue
- bilateral symmetry
- move like a snake (expand/compress)
- hermaphrodite sexual repro
Annelida
ex: earthworms, leeches
- clade = Lophotrochozoa
- segmented with body cavity
- bilateral symmetry
- move likes a snake
- hermaphrodite sexual repro
Nematoda
ex: pinworm, roundworm
- clade = Ecdysozoa
- grows by shedding/molting
- eat from being parasites
- have a hardened cuticle/outer skin
- microscopic
- sexual repro
Arthropods
ex: crustaceans, chelicera, insects
- clade = Ecdysozoa
- sheds/molts exoskeleton
- jointed appendages
- have a nerve cord
- 3 body sections (head, thorax, abdomen)
- sexual repro in water
Crustaceans
ex: lobsters, crabs

arthropod w/ very hard exoskeleton, live in water
Chelicera
ex: spiders, tics, scorpions, horseshoe crabs

arthropod w/ a biting mouth
Insects
ex: beetle, ant

arthropod that can fly, has 6 legs
Echinodermata
ex: starfish, sea urchin
- clade = Deuterostomia
- larvae are bilateria symmetric
- short digestive tract
- water vascular system
- 5 body sections
What are some distinguishing features of vertebrates? Which other animal phyla are they related to?
- Related to chordates - have a notochord (spine), dorsal / hollow nerve cord, muscular, post-anal tail, and pharyngeal slits/clefts at some point in their life cycle
- Vertebrates have a backbone
Lancelets
- invertebrates
- small & blade-shaped
- marine animals
- feed on plankton
Tunicates
ex: sea squirts
- invertebrate
- larvae has chordate features
- eat through filtration
- adults show no symmetry and don't move
- no head
- asexual repro by budding
Hagfish
- reduced vertebrae (no backbone)
- slime glands
- eel-shaped
- bottom-dwelling scavengers
Lampreys
- cartilage vertebrae (no backbone)
- developed a skull
- act as parasites to other fish
Sharks/rays
- gnathostomes
- cartilage skeleton
- developed a jaw
- became fierce predators
ray-finned fish
ex: common fish (tuna, bass, etc)
- bony endoskeleton & swim bladder
- fins supported by bony rays
lobed finned fish
ex: coelacanths
- bony endoskeleton & swim bladder
- rod-shaped & lobed muscular fins
lungfish
- ability to breathe air
- burrow in mud
- have lobed fins
- freshwater
tetrapods
ex: amphibians, reptiles, mammals
- 4 limbs with digits
- neck/ears
- absence of gills in adults
amphibians
ex: salamanders, frog
- lay larvae (eggs) in water
- skin permeable to oxygen
- metamorphosis from tadpoles to frogs
reptiles
ex: lizards/snakes, birds/dinosaurs/crocodiles/turtles
- have an amniotic egg that's waterproof
- scales
- lay shelled eggs on land
- fertilization occurs internally before eggshell is formed
mammals
- amniotes with hair that produce milk (mammary glands)
- high metabolic rate due to endothermy
- larger brain relative to body size
- differentiated teeth
3 clades of mammals
- Monotremata (platapus) - lays eggs
- Marsupials (opossum, kangaroo) - pouch attached to nipples
- Eutherians (humans) - placenta
Why do we say the birds are living dinosaurs?
Birds are descendants of the common ancestor of the dinosaurs, a monophyletic clade of dinosaurs must include birds
Who are tetrapods related to?
Tikaalik = a fossil with both fish (scales, fins) and tetrapod characteristics (neck, ribs)
Where and when did humans evolve?
200,00 years ago in Africa
Why is it incorrect to say that humans evolved from chimpanzees?
We share a common ancestors with chimpanzees, chimps still exist today
What are some of the major threats to biodiversity?
- Climate change (polar bears)
- Exploitation/hunting (elephants)
- Disease (frogs)
How does the current rate of extinction compare to past mass extinctions in the fossil record?
It far exceeds previous mass extinctions
Small population approach to conservation
- emphasizes the various processes that cause extinctions once population sizes have been greatly reduced
- extinction vortex = the shrinking of small populations driven by genetic drift
Declining population approach to conservation
- focuses on threatened and endangered populations that show a downward trend
- looks at environmental factors that caused a population decline in the first place
What is your "ecological footprint"?
the impact of a person or community on the environment, expressed as the amount of land required to sustain their use of natural resources
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