Find study materials for any course. Check these out:
Browse by school
Make your own
To login with Google, please enable popups
To login with Google, please enable popups
Don’t have an account?
To signup with Google, please enable popups
To signup with Google, please enable popups
Sign up withor
What is unique about the structure of mitochondria and chloroplasts?
Why don’t antibiotics like streptomycin harm our own cells?
All ribosomes share...
Similar rRNA sequences
a small subunit that decodes mRNA
a large subunit that joins amino acids together
is a well substantiated explanation of some aspect of the natural world that can incorporate facts, inferences, laws, tested hypotheses and other theories. example: gravitational theory. example of a law: newton's law of motion. Laws are mathematical descriptions
If certain assumptions are met, allele and genotype frequencies will not change from generation to generation in a population.
p + q = 1
p = frequency of one (dominant) allele
q = frequency of other (recessive) allele
p² = frequency of homozygous dominant phenotype
The study of genetic variability in a population and the forces that act on it.
proportion of a genotype in the population
Proportion of an allele of a given genetic locus in the population
1. Genetic variation exists among individuals in population.
2. Reproductive ability of each species causes populations to geometrically increase over time.
3. Organisms compete with one another for resources: food, living space, water, light.
4. Offspring with most favorable characteristics are the most likely to survive and reproduce. They get to pass genetic characteristics to next generation.
Or synthetic theory of evolution. Combines Darwin’s theory of evolution by
natural selection with modern genetics. Explains source of variation in populations (mutation). Also, how species adapt to their environment (combination of Darwin’s premises of natural selection with understanding of the mechanisms of inheritance)
Restrict gene flow between species. Pre-zygotic barriers prevent fertilization from taking place. Post-zygotic barriers prevent gene flow after fertilization has taken place (reproductive isolating mechanisms).
Populations diverge into different species due to geographic isolation, or physical separation.
Populations become reproductively isolated from one another despite living in the same
Evolution proceeds in spurts – short periods of active speciation interspersed with long periods of stasis (inactivity).
Populations slowly diverge from one another by accumulation of adaptive characteristics
and RNA sequences, there is a close match between charophytes and land plants.
Nonvascular (lack xylem and phloem) unlike other land plants
Dominant gametophyte (1n) generation unlike other plants
Sporophytes (2n) remain permanently attachedNutritionally dependent on gametophytes
Which process is necessary for plants to move from the diploid sporophyte generation to the haploid gametophyte generation?
Green moss gametophyte bears archegonia / antheridia at top of plant
Fertilization – sperm cell fuses with egg cell in archegonium (zygote)
Zygote grows into an embryo. Develops into a moss sporophyte attached to a gametophyte.occurs within capsule of sporophyte
When spore germinates
–forms buds that develop into gametophytes
Have adaptations that algae and bryophytes lack such as vascular tissues and a dominant sporophyte generation. Reproduction remains dependent on water as a transport medium for motile sperm cells (as in bryophytes).
Largest and most diverse group of seedless vascular plants. Fern sporophyte consists of a rhizome that bears fronds and true roots.
A plant sporophyte embryo
A protective coating
Seeds are totally exposed or borne on the scales of cone
Ovary wall does not surround the ovules
Are vascular plants, unlike bryophytes
Produce seeds, unlike bryophytes and ferns
Produce wind-borne pollen grains, unlike ferns and other seedless vascular plants.
Vascular plants that produce flowers and seeds enclosed within a fruit (a mature ovary)
Most diverse and successful plant group
Largest phylum of gymnosperms
Woody plants that bear needles (leaves that are usually evergreen) and produce seeds in cones
Most are monoecious, meaning they have male and female reproductive parts in separate cones on same plant
Palm-like or fern-like in appearance
Dioecious, meaning they have male and female reproductive structures on separate plants but reproduce with pollen and seeds in cone-like structures.
Ginkgo biloba is only surviving species in phylum Ginkgophyta. It is a deciduous, dioecious tree.
Female ginkgo produces fleshy seeds directly on branches.
A mature plant ovary, sometimes with accessory tissue(s)
Reproduce sexually by forming flowers. After double fertilization, seeds form within fruits. Wind, water, insects, animals transfer pollen grains.
Efficient water-conducting vessel elements in xylem
Efficient carbohydrate-conducting sieve tube elements in phloem
Angiosperms, which compose a single phylum, dominate in most terrestrial ecosystems, and exhibit great diversity in both vegetative and reproductive structures.
Mutualistic relationships between fungi and roots of plants. Fungus supplies water and nutrient minerals to plant. Plant secretes organic compounds needed by fungus.
Symbiotic combination of fungus (generally an ascomycete) and a photoautotroph (alga or cyanobacterium). The photoautotroph provides fungus with organic compounds. Fungus provides shelter, water, minerals
Lichens have 3 main growth forms: crustose, foliose, fruticose
Lichens are a symbiosis of 2 organisms but are sometimes considered one organism because they form such a tight fusion.
According to current hypotheses, fungi evolved from a unicellular, flagellate protist and diverged into five main groups.
as foods (mushrooms, morels, truffles)
in production of beer, wine, bread (yeasts)
to produce cheeses and soy sauce
to make citric acid and other industrial chemicals
for research -- model organisms for molecular biology and genetics – yeast Saccharomyces cerevisiae
Medication -- penicillin and other antibiotics
fungi are opportunistic pathogens in humans
Fungal hyphae infect plants through stomata
–hyphal branches penetrate plant cells
–obtain nourishment from cytoplasm
Includes wheat rust, Dutch elm disease, chestnut blight
–development of mouth from blastopore
Sponges are animals characterized by flagellate collar cells (choanocytes)
The only members of the Parazoa
Sponge bodies consist of a sac with tiny openings for water to enter, a central cavity (spongocoel), and an open end (osculum) for water to exit
Sponge cells are loosely associated and do not form true tissues
Characterized by radial symmetry, two tissue layers, and cnidocytes (cells containing nematocysts)
Gastrovascular cavity with a single opening for mouth and anus
Nerve cells form irregular, nondirectional nerve nets that connect sensory cells with contractile and gland cells
–fragile, luminescent marine predators
–biradial symmetry and two tissue layers
–eight rows of cilia that resemble combs
–tentacles with adhesive glue cells
True coelom is a fluid-filled body cavity completely lined by mesoderm between the digestive tube and the outer body wall
Allows tube-within-a-tubebody plan – body wall is outer tube, and inner tube is digestive tube
An enclosed compartment (or series of compartments) of fluid under pressure
Serve as hydrostatic skeleton – contracting muscles push against tube of fluid
A space in which internal organs develop
Helps transport materials
Protects internal organs
Acoelomate animals with
–3 definite tissue layers
Many are hermaphrodites, or single animals that produce both sperm and eggs.
Class Turbellaria -- free-living flatworms, including planarians
Classes Trematoda and Monogenea – parasitic flukes
Class Cestoda – parasitic tapeworms
Evolution of a head
–concentration of sense organs and nerve cells (simple brain) at anterior end
–(Flatworms show beginnings of cephalization)
Increases effectiveness of bilateral animal
–to actively find food, shelter, mates
–to detect enemies
Most have open circulatory system – Cephalopods have closed circulatory system
Most have rasplike radulafor feeding – Bivalves are suspension feeders
Most marine mollusks have free-swimming larva
Aquatic worms, earthworms, leeches
Conspicuously long bodies
Segmentation is present both internally and externally
A large, compartmentalized coelom serves as hydrostatic skeleton
–Important research organism: C. elegans
Segmented animals with paired, jointed appendages
Armor-like exoskeleton of chitin
Molting is necessary for arthropod to grow
ex. Myriapods, arachnids (scorpions, spiders, etc.)
Lobsters, crabs, shrimp, pill bugs, barnacles
Body with cephalothorax and abdomen
Most have five pairs of walking legs
Which of the following is an insect?
Sign up for free and study better.
Get started today!