Biology Q4 Flashcards
What are the 3 types of natural selection?
- Directional Selection - Favors one extreme characteristic
- Stabilizing selection - Favors moderate characteristic
- Disruptive selection - Favors multiple extreme characteristics (causes new species development)
Species
A population that will not interbreed with other species under natural circumstances
Allopatric Speciation
Speceis formation initiated by geographic separation
Sympatric Speciation
Species formation initiated without geographic separation
Evolution
Genetic change over time
How many mass extinction events have occurred? What was the most recent?
5 mass extinction events
Dinosaur extinction most recent
5 Types of Selection Pressures
- Competition for food
- Competition for mates
- Predation
- Environmental changes
- Parasites
What are the four basic principles of evolution?
- Variation (different members of the same species have different characteristics)
- Heritability (Traits are passed down from parent to child)
- Differential Reproductive Success (Organisms with traits better suited to their environment have more offspring)
- 99.9% of all species are extinct
What percent of cells in the human body are nonhuman?
90%
Plasmid
A circular DNA molecule
3 types of plasmid
- Metabolic Plasmid
- Resistance Plasmid
- Virulence Plasmid
What are the 3 ways antibiotic systems destroy pathogens?
- Inhibiting cell wall synthesis
- Inhibiting protein synthesis
- Inhibiting DNA production
How are bacteria classified?
By their shape
What are the 3 ways bacteria perform genetic exchange?
- Conjugation (transfer directly from 1 bacteria to another)
- Transduction (Transfer via viruses)
- Transformation (release of genetic information from a burst bacterium)
3 Examples of non-vascular plants
- Mosses
- Liverwort
- Hornwart
2 divisions of vascular plants
- Seeded
- Seedless
How archaea differ from bacteria (2 ways)
- Chemical composition of cell wall, flagella, plasma membrane
- DNA sequence
What sort of environments to archaea thrive in?
Those too extreme for most other organisms
2 factors that separate protists from bacteria and archaea
- Larger size (still usually single cell though)
- Eukaryotic
3 Varieties of protists
- Animal-like (move and hunt for prey)
- Plant-like (photosynthesize)
- Fungus-like (heterotrophs that form sheet-like colonies)
Slime Molds
Fungus-like protists
Structure of a virus
- Capsid and plasma membrane containing genetic material (DNA or RNA)
How do viruses reproduce?
- Inject genetic material into a living cell
- Viral genetic material copies itself
- Uses host’s ribosomes, etc, to produce new proteins
- Proteins are ejected from host, assembled into new virus
Why do RNA viruses evolve more quickly than DNA viruses
DNA replication has an “error checking” enzyme that prevents many mutations
What determines which cells a virus can invade?
Glycoproteins on the outside of the virus
Xylem
Phloem
Plant veins that carry water an minerals upwards
Plant veins that carry metabolic products downwards
How do xylem transport substances upwards?
Evaporation causes water to move upwards due to adhesion, assisted by lignin in water-transporting molecules
What was the major change pollination made to plant reproduction
Loss of reliance on water, instead using wind and animals for pollen movement
Bryophyte
Another term for nonvascular plant
Seed
A plant embryo surrounded by a protective coat
2 classifications of seed plants
Gymnosperms (non-flowering, “naked-seed”, e.g. conifers)
Angiosperms (flowering)
Describe reproduction of mosses
- Sporophyte released spores
- spores become gametophytes (haploids w/ one gender or another, “normal” moss)
- Sperm from male gametophyte travels to female gametophyte via water
- fertilized embryo creates sporophyte
2 differences between monocots and dicots
- Monocots have 1 cotyledon, while dicots have 2
- Monocots have parallell veins, while dicots have netlike veins
3 characteristics of living vascular plants
- Life cycle composed mainly of sporophytes
- Presence of Xylem/Phloem
- Well-developed roots and leaves
Describe the life cycle of a fern
- A fern develops spores inside of sporangia
- Spores are released and become gametophytes
- Sperm from gametophytes are transported to eggs via water
- A sporophyte is formed
What type of plants are the most diverse?
Angiosperms
When did angiosperms begin to replace gymnosperms?
End of the Mesozoic
Stamen
The male portion of a flower, consists of anther and filament
Carpel
The female portion of the flower
Consists of the stigma (top), style (stalk), and ovary
Three key characteristics of animals
- All are capable of locomotion
- All are heterotrophs
- All are multicellular
4 criteria by which animals are divided?
- Does the animal have specialized cells that form tissues?
- Does the animal have radial or bilateral symmetry?
- Does the GI tract develop back-to-front or front-to-back?
- Continuous growth or molting?
Protostomes
Animals whose GI tracts are developed front-to-back
(Flat worms, arthropods, mollusks etc.)
Deutrostomes
Animals whose GI tracts are developed back-to-front
(Vertebrates and echidnoderms)
4 characteristics of sponges
- No organs or specialized cells
- Body consists of hollow tube with pores in its wall
- Filter feeders
- Larvae are free-swimming, adults are sessile
2 Characteristics of Cnidarians
- Radial symmetry
- Tentacles lined with stinging cnidocytes, used to paralyze prey
- Alternating generations of sessile polyps and free-floating medusae
- Can reproduce sexually and asexually
3 Major groups of cnidarians
- Corals
- Sea anemones
- Jellyfishes
3 most diverse animal phyla
3 - Nematoda (roundworms)
2 - Mollusca
1 - Arthropoda
4 Characteristics of Flatworms
- Well-defined head and tail regions
- Hermaphroditic
- Can reproduce sexually or asexually
- Some have single body opening that acts as both mouth and anus
5 Characteristics of roundworms
- Long, narrow unsegmented body
- Bilateral symmetry
- Surrounded by strong, flexible cuticle
- Must molt to grow
- Full GI tract, protostomes
1 Characteristic of Annelids
- Segmented worms
3 Categories of Annelids/segmented worms
- Marine polychaetes
- Earthworms
- Leeches
Polychaetes
Marine segmented worms, “may bristles”
3 types of mollusks
- Gastropods
- Bivalves
- Cephalopods
4 characteristics of arthropods
- Segmented body
- Chitin exoskeleton
- Jointed appendages
- Protostomes
4 types of arthropods
- Insects
- Arachnids
- Crustaceans
- Millipedes/centipedes
Earliest (evolutionarily) creatures able to fly
Insects
4 Types of Echinoderms
- Sea Stasr/sand dollars
- Sea Urchins
- Sea cucumbers
4 characteristics of echidnoderms
- Enclosed by hard skeleton under spiny skin
- Larvae are bilaterally symmetrical and share anatomy features with chordates
- Adults are radially symmetrical
- Undersides covered in tube feet
4 common structures of chordates
- Notochord
- Dorsal hollow nerve cord
- Pharyngeal slits
- Post-Anal tails
Notochord
A rod of tissue extending from the head to the tails
Kept throughout life in simpler vertebrates, but replaced by backbone in more complex chordates
Pharyngeal Slits
Gill-like slits in neck
Disappear during development in many chordates
2 evolutionary changes in mammals that led to endothermy
- Longer legs increased locomotion, which increases cellular respiration and thus more heat
- Hair allows for heat to be trapped and used for temperature regulations
3 categories of mammals
- Monotremes (platypus and echidna)
- Marsupial
- Placental mammal
How long does it take for one E. Coli bacterium to become 20 million?
12 hours
Chermorganotrophs
Bacteria that feed on organic matter
Chemolithotropes
Bacteria that feed on nonorganic matter
