Ch. 19h – Microbes

Prokaryotes – single celled, no nucleus or membrane bound organelles

- Bacteria and Archaea

Structure

- Shape – rod (bacilli), sphere (cocci) or spiral (spirilla)

- size = 1-5 um (eukaryotes cells 10-100 um)

- have cell wall (with peptidoglycan) which differs across species → this creates a way to differentiate species → called gram staining

- cell wall is surrounded by a capsule = extra protection, sticky

Move – use flagella= long whiplike structure

Energy:

Autotroph- makes its own food, phototroph, chemotroph

Heterotroph – ingest food

“Breathing”:

Anaerobic – doesn’t need oxygen to survive

Aerobic – needs oxygen to survive

- some organisms can switch between these

Reproduction – binary fission – double and divide

Conjugation- transfer of information

Genetics

- small amount of ringed DNA, usually compacted in an area called the nucleoid, also has small plasmids → extra genes

- very little protein

- still has DNA replication but RNA and proteins differ, this allows us to attack with selective antibiotics

Jobs:

Decomposers, N- Fixers

Pathogens – disease causing agents, strep, Tb

Biotechnology – use to engineer medicine and food

Food production – milk, cheese

Control – sterilize, low temperatures, low air

Virus – particle of nucleic acid, protein or lipid that reproduce by infecting other cells, p353 pix, Are they living?

- made of a protein coat (capsid) with DNA or RNA inside, p354-5

Infection

Bacteriophage – virus that infects bacteria

1) Lytic – virus enters a cell, reproduces and the cell to bursts

2) Lysogenic – virus inserts its DNA into the cell, the cell makes the DNA part of its own, thus makes more viruses

- ex. Polio, measles, HIV, flu

- some viruses have been linked to cancer, ex. MS

Viroids – short strand of RNA without a capsid

Prions – proteins that have the ability to alter DNA, inherited?

- Resistant to extreme heat and conditions that kill organisms

- cause Mad cow, CJD

Protist

- most diverse eukaryotes, uni or multicellular, most are aerobic, some photosynthetic, most have flagella or cilia, some are sexual (syngamy) and have mitosis/meiosis unicellular,

≈ 1.5 billion years old, 200,000 species

Evolution from prokaryotes

→ folding of plasma membrane may have created ER

→ mitochondria and chloroplasts moved into prokaryotes in a symbiotic relationship (endosymbiosis – Margulis)

3 main types

1) Animallike –have some characteristics of animal cells, many have movement with cilia & flagella (ciliates/flagellates)

- obtain food through membrane or engulf

- have fake feet to help move = psuedopods

- some are pathogens (malaria), some are food source, some do good (termite)

- ex. Paramecium (p 372) , Amoeba (p 370)

2) Plantlike – have characteristics of plant cells, some are algae, undergoe photosynthesis

- contain chlorohyll to capture light

- ex. Euglena (p 369), dinoflagellates, diatoms (p368)

- can cause blooms in the water and take surrounding nutrients, many symbiotic relationships (photoplankton)

- used in food, ice cream

3) Funguslike – heterotroph that absorb nutrients like a fungus, but cell wall differs

- ex. slime molds, water molds, caused potato famine in 1845

Ch. 20 – Fungi

- eukaryotic heterotrophs with cell walls made of chitin

- either: *saprophytes (decomposers), parasites or symbionts

- made of filaments called hyphae that tangle together called mycelium – p 378

- the top is the fruiting body

- reproduce sexually and asexually

- under the mushroom cap, there are gills which contain the spores

- many cause diseases ex. Ringworm, athlete’s foot

- recycle nutrients back to the environment

- ex. Bread mold, mushrooms, penicillin, imperfect

- symbiotic ones – lichens = fungus and a photosynthetic organism

Ch. 21 & 23 Plants

- multicellular eukaryotes that have a cell wall made of cellulose

Algae –type of plant that lives in the water

- 1^st plant, based on evolution

- produce a large part of the earth’s free oxygen

Bryophytes- moss, liverworts, hornworms

- can live on land, but need to be near water for reproduction and nutrients, do not grown tall because don’t have vascular tissue

- have alternation of generation life cycle – p 398

Ferns – first vascular plants this allows them to grow taller

- xylem – carries water up, phloem – carries sugar up and down

- don’t produce seeds, but spores on the bottom of their leaves, p401 – relies on water or air to move spores

Seed Plants – have seeds to allow them to live on land, wind or animals move seeds, p402

Gymnosperm- cone bearing tree = conifer

Angiosperms = flowering plants – have flowers to aid in pollination

Specialized tissues

Roots – absorb water and nutrients, anchor plant, p585

- Taproot (carrot) vs fibrous root – increase surface area

- Monocot vs. Dicot – p453

Stem – holds plant up, made of vascular tissue = vein, p461

- ends of the stem are called apical meristem = most growth

- grow outward to form bark, rings

- primary vs. secondary growth – p463

Leaves – photosynthetic part

- structure p465

- functions in gas exchange using stomata

Transport

- occurs in xylem and phloem

- uses diffusion, adhesion (to sides) and cohesion (to itself)

- pressure flow theory- p476

- transpiration – plant sweats

Reproduction

- alternation of generation = life cycle of a plant, N to 2N and back to N ( p 406) – sporophyte vs. gametophyte

- flower = reproductive organ, can produce fruit (contain seeds)

- picture on p495

- seeds develop based on environmental cues

- critical night length

Response

- plants have hormones – p509– auxin, ethylene etc.

- respond to light, gravity and touch

Ch 22- Animals

Characteristics of animals

1) multicellular, heterotrophs (ingest food), eukaryotes

2) Lack cell walls – collagen and junctions instead

3) Dominant generation is diploid

4) Most are motile for some of their life

5) Have muscle and nervous tissue

6) have embryonic development that forms layers of tissues

Phylogeny of animals – p413

1) Increased tissue complexity

2) body symmetry changed – radial = top or bottom but no sides/back →bilateral= has 2 sides, can cut in “identical halves”, p414

- cephalization = concentration of senses toward the anterior

3) body cavity increased complexity

acoelomates – no cavity, solid body, ex. Flatworm, tapeworm

pseudocoelomate = not completely lined cavity from mesoderm, ex. Roundworms, rotifer

coelomates = have a coelom = fluid lined space that separates digestive system from the rest of the body made from mesoderm

4) cleavage - early cell divisions of the zygote tto make coelom , p415

Major phyla – p416-417

Invertebrates - no true backbone

Sponges – oldest animals, no mouth, few specialized tissues, no organs, no true movement, filter feeders, p418

Cnidarians – soft bodies animals with stinging tentacles, radial symmetry and specialized tissue, some nerve tissue, feeding cavity, ex. Simple jellyfish, p419

Platyhelmites = Unsegmented Worms – brain, nerves, digestive system, “blood”, most are hermaphrodites, ex. flatworm p421

Nematoda- worms with some body cavity called a pseudocoelom, roundworm, flatworms, *p424 tapeworms, C. elegans

Annelids – segmented worms, internal organs with a coelom, p425

Mollusks – soft bodied organism with a shell, complex feeding, gills, open circulation, sexual repro. ex. snails, octopus, bivalves (2 shell), p431

Arthropods –largest phylum, have segmented bodies, exoskeleton and jointed appendages, ex. Spiders, crustaceans (lobster), insects

Echinoderms – spiny skinned animals, internal skeleton, water vascular system, suctioning tube feet, radial (5 part) symmetry, ex. Starfish

- invert evolution

- digestion – moves intracellular and more complex

- respiration – increases surface area, specialized organs

- circulation – open to closed with vessels and 4 chambered heart

- response – increased nerve tissue

- reproduction – sexual gives diversity

Chordates – have a notochord = hollow dorsal nerve cord (no true backbone), pharyngeal slits, tail

Phyla Chordate - includes 2 invertebrate groups → lancelets and tunicates (closest invertebrate to human) and then the vertebrates

Fish – aquatic animals with scales, fins and gills (breathe), p437

- 3 types – jawless fish (lamprey), sharks (Chondrichthyes =cartilage) and bony fish (osteichthyes- tuna, perch)

Amphibians – animals that can are in water as larvae and on land as adults, 3 chambered heart, ex. Frog, some dinosaurs?, evolution

True Vertebrates - true backbone

Reptiles – animal with lungs, scaly skin, and born by an egg, still ectothermic (cold blooded), ex. Lizard, snake, some dinosaurs, turtle

Birds – endothermic (regulate body temp.- warm blooded) reptilelike animals, with feathers, crop, 2 legs and usually useful wings

Mammals – endotherms, hair, mammary glands, breath air, 4 chambered heart, ex. Apes, dogs,

- changes in brain, teeth, heart

- monotreme (lay eggs), marsupial (live young in a pouch), placental (live young) – p444

Humans

- 500,000 years ago, the first Homo sapiens appeared

Primate = flat face, small nose, binocular vision (2 eyes forward, 3-D view), flexible fingers, rotating arms and larger cerebrum

- 2 branches of primates –

-2 branches of anthropiods – separated 45 mil y.a.

1) new world monkeys – tree dwellers

2) old world monkeys- land dwellers

Hominids- closest relative to human, descendant of hominoid

- omnivores, walked on 2 feet (bipedal), large brain

- our closest relative is the chimpanzee

Evolution of Hominids

1) Australopithecus – 1^st, Lucy, 1^st upright walker

2) Homo habilis – larger brain, vegetarian

3) Homo erectus – 1 mil y.a., even larger brain, omnivore

4) Homo sapiens – 500,000 y.a. “old” humans,

- Cro-Magnon – 100,000 y.a., 1^st modern humans

- many questions remain