final Flashcards
alteration of generations
life cycle that includes the alteration between multicellular haploid and multicellular diploid stages
sporophyte
multicellular diploid (2n) form that produces haploid spores (n) through meiosis
gametophyte
multicellular haploid (n) form that produces haploid (n) through mitosis
non-vascular plants
seedless plants
non vascular seedless plants
gametophyte- dominant
sporophyte- reduced, dependent on gametophyte for nutrition
vascular plants
seedless plants, seed plants such as non-flowering gymnosperms and flowering angiosperms
vascular seedless plants
gametophyte- reduced, independent: photosynthetic and free living
sporophyte- dominant
non-flowering gymnosperms
gametophyte- reduced (usually micrscopic), dependent on surrounding sporophyte tissue for nutrition
sporophyte- dominant
flowering angiosperms
gametophyte- reduced usually microscopic, dependent on surrounding sporophyte tissue for nutrition
sporophyte- dominant
pollen grain
special type of spore that gives rise to sperm
angiosperm life cycle includes double fertilization
- the pollen tube reaches the ovule, one of the two sperm fuses with the egg to form a zygote
- the other sperm fuses with the 2 nuclei in the middle to form an endosperm (which has 3 sets of chromosomes and is triploid or 3N)
after double fertilization
ovule matures into a seed, zygote develops into a sporophyte embryo and the triploid central cell of the gametophyte develops into endosperm
characteristics of angiosperm
- coevolution with animal pollinators
- double fertilization
- fruit: protects the seed and helps them to disperse
- flowers: reproductive structure, female reproductive structure
microspore
two haploid sperm nuclei
megaspore
one haploid egg nucleus and two haploid polar nuclei
one sperm and egg =
embryo (2n)
one sperm and two polar nuclei=
endosperm (3n) which nourishes embryo
what is a result of double fertilization
a diploid zygote and a triploid endosperm
advantages of plants on land
more sunlight available and less competition
disadvantages of plants on land
lack of water and structural support
the best description of the first land plants is
small, leafless and without roots or flowers
how did plants adapt to being on land
the move to land required protection from desiccation of gametes and embryos, as wall as a new means of gamete and embryo dispersal
waxy cuticle
covering the surface of the plant shoot is an effective barrier to desiccation because it prevents loss of water to the air
stomata
it is necessary for plants to have pores through which gasses can be exchanged with the environment
vasculature tissue
allowed plants to dominate the landscape- provides a means for transport and structural support for the body of the plant
lignin
associated with vascular tissue and plays a role in conducting water around the body of the plant- a stable molecule that provides structural support to plants and does not break down easily
seeds
- multicellular, usually diploid, larger and can contain a large amount of storage material
- presence of storage material in seeds allows some seeds to survive for long periods of time until the appropriate environmental conditions for growth arise
population
a group of interbreeding organisms that are members of the same species living in the same area at the same moment
p + q = 1
describes allele frequencies and genotype frequencies
allele frequency
genetic makeup of a population can be described by the frequency of the alleles that exist in a population
genotype frequency
the percentage of individuals in a population that have a specific genotype
p
frequency of allele A
q
frequency of allele a
p2
frequency of genotype AA
2pq
frequency of genotype Aa
q2
frequency of genotype aa
type A
IAIA or IAi
type b
IBIB or IBi
type AB
IAIB
type O
ii
gene flow
the movement of alleles from one population to another usually by migration
genetic drift
random fluctuations in allele and genotype frequencies
bottleneck effect
an effect that reduces the population by a significant amount
founder effect
when a few individuals are geographically separated from the original population
gene flow occurrence, pop size, reason and evolution
- occur through migration from one to another population
- larger popluation
- inbreeding or inbreeding through migration
- through migration
genetic drift occurrence, pop size, reason and evolution
- occur through random event or sampling
- smaller populations
- sudden change or sampling error
- through bottleneck or founder effect
criteria for hardy-weinburg equilibrium
no mutations, random mating, no gene flow, large pop size, no natural selection
characteristics of animals
multicellular, motile and ingestive heterotrophs
which characteristics can be used to distinguish a parazoan from a eumetazoan
lack of true tissues
what are the first animals?
parazoa and eumetazoa
parazoa
no symmetry or true tissue
ex. sponges
eumetazoa
symmetry (radial and bilateral) and contain true tissue
bilateral
body cavity and complete digestive
pseudocleums
incompletely lined with mesoderm
ex. nemotoda
coelmates
body enclosed in mesoderm and have a true colem (body cavity)
ex. protosomes and deutrosomes
bilateral symmetry in animals is best correlated with
motility and active predation and escape
eumetozoa
symmetry and true tissue
radiata
radial symmetry, diploplastic and no muscles/mesoderm
ex. cnidaria
bilateria
triploblastic and true muscle
acelomates
no body cavity and incomplete digestive tract
ex. flatworms
protosomes
mouth first, anus second
no segmentation
mollusca - snails
segementation
single segmented annelids (segmented worms) and advanced arthopoda (insects-have exoskeletons)
deutrosomes
mouth second, anus first
echinoderms
sea stars, radially symmetrical but are bilateral during early development
chordates
invertebrates, vertebrates and have notochord, nerve cord, pharyngeal slits and postanal tail
which grouping includes the largest number of species
invertebrates
free living flatworms, roundworms and segmented worms share all of the following traits except
digestive tract with mouth and anus
