Exam 4 Flashcards
what do seeds give plants
survival adpatation
what does a seed do
protect enclosed embryo with a seed coat, contains stored food, and can reman dormant
seeds
mature ovule containing an embryo
how many generations is a seed composed of
3
what are the 3 generations in a seed
offspring (seedling generation) (2n) - embryo
megagametophyte (n) - stored food
seed coat is maternal tissue (parent generation) (2n) - seed coat
characteristics of seed plants
are the heterosporous or homosporous
all are heterosporous
characteristics of seed plants
where is megagametophyte retained
within the original megasporangium
characteristics of seed plants
how many additional layers of tissue, enclose
one or two
characteristic of seeds plants
what is the tissue that encloses seed called
integument
characteristic of seed plants
what is the opening at the apex of the megasporangium called
micropyle
characteristic of seed plants
what is an ovule
nucellus and integument
characteristic of seed plants
what happens after fertilization
ovule develops into seed
integument develops into seed coat
what is the nucellus
megasporangium
what is not required for male gamete to reach egg
water
what carries pollen
water, air, or animals
what do all seed plants posses megaphylls or microphylls
megaphylls
division coniferophyta
pine- most familiar,
dominate forests in northern parts of north America and Eurasia
what is the stage from sporophyte to microspore called
microsporogeneis
what is the stage from microspore to microgametophyte called
microgametogenesis
what is the stage from sporophyte to megaspore called
megasporogenesis
what is the stage from megaspore to megagametophyte called
megagametogenesis
what is created from the microgametophyte
pollen gram
what is the embryo in gymnosperms
the seed
pine life cycle
separate male and female cones, usally same tree
microgametophyte development
microsporogenesis (in microsporangia on pollen cone)
gymnosperms
O(2n)- microsporophyte
O (n) O (n) meiosis 1
O (n) O (n) O (n) O (n) meiosis 2
4 microspores (n) results
microgametogenesis
gymnosperms
O (n)- microspore
O O O O 4 cell stage
x x tube cell generative cell
no function pollen tube O O
stalk cell spermatoginous cell
x O O
no function sperm sperm
3 stage 2 sperm and tube cell
megagametophyte development
gymnosperm
cones larger than male cones- woody texture
ovules are borne on upper side of cone scales
each ovule contains a single megasporocyte (2n) undergo meiosis
megasporogenesis (in ovule)
gymnosperm
O (2n) megasporocyte . (n) O (n) meiosis 1 . (n) . (n) . (n) O (n) meiosis 2 x x x 1 functional megaspore (n)
megagametogenesis
gymnosperm
megasporangium to megaspore (n) to megagametophyte (n)
when does pollination occur
gymnosperm
prior to megaspore development
seed cone scales open widely at this time but close after pollination is completed
megagametophyte development
gymnosperm
after 15 months since pollination 2 or 3 archegonia develop on micropylar end of megagametophyte
fertilization in seed plants
gymnosperm
egg in archegonium occurs 15 months after pollination
pine seeds usually shed during autumn or year following pollination
where do seeds, no antheridia, and pollen tube show on a cladogram
between monilophyta and cycadophyta
where do flower and fruit, vessel elements, and double fertilizations show on a cladogram
between coniferophyta and anthophyta
division cycadophyta
palm like plants, leaves form clusters at tip of stem
warmer climates
division ginkgophyta
Ginkgo Biloba
division gnetophyta
gnetum and allies 3 families, each with one species gnetum ephedra weltischia mirabilis
angiosperms
very diverse group
comes from reproductive success of flowering plants
range from 1 cm to >100m
some are vines, epiphytes, succulents such as cactus, some are aquatic
some are parasitic (dodder) and saprophytes (Indian pipe)
2 characteristics of angiosperms
flowers
fruits
what are the 2 traditional classes of angiosperms
monocotyledon
dicotyledon
typical angiosperm life cycle
all are heterosporous
gametophyte are greatly reduced in size
both antheridia and archegonia are missing
how many cells are in a mature microgametophyte
3
how many cells are in a mature megagametophyte
7
where is the sporophyte in life cycle
in anther from microsporogenesis to microgametogenesis
where is the sporophyte in life cycle
in ovule from megasporogenesis to embryo
pollination in angiosperms is
indirect
pollination in angiosperms
pollen is deposited on stigma
pollen tube then grows and delivers 2 nonmotile sperm to megagametophyte
the ovule develops into seed which is enclosed in mature ovary (fruit)
microsporogenesis in anther
angiosperms
O (2n) microsporocyte
O n O n meiosis I
O n O n O n O n meiosis II
4 microspore (n)
microgametogenesis in anther
angiosperms
O (n) microspore
tube cell O n O n
pollen tube O n O n generative cell inside (tc)
sperm sperm
microgametogenesis
angiosperms
pollen grains develop hard outer wall- the exine- made of sporopollenin
pollen is ready to be released from anther
what is microgametophyte called in angiosperms
pollen grain
what is mega gametophyte called in angiosperms
embryo sac
pollen in angiosperms
pollen varies greatly in size and shape
can be used diagnostically
ancient communities have been reconstructed based on ancient pollen in lake sediment- palynology
megasporogenesis in angiosperms
ovule- consists of stalk or funiculus with nucellus and one or two integuments
micropyle (opening) at one end
megasporogenesis order
megasporogenesis in nucellus/megasporangium in ovule
megasporogenesis
angiosperm
O (2n) megasporcyte
. n O n meiosis I
. n . n . n O n meiosis II
4 megaspores 1 functional megaspore
megagametogenesis
angiosperms
O n 1 megaspore 3 mitotic divisions
3 antipodals (chalazal)
2 polar nuclei
2 synergists and 1 egg (micropylar)
what is in a mature megagametophyte
“embryo sac” 7 cells 8 nuclei
pollination and fertilization in angiosperms
1 pollination
2 pollen grain germinates and takes up water
3 flower stigma and stalk modified to facilitate pollen grain germination and growth of pollen tube
4 pollen tube enters ovule through micropyle and penetrates one of the synergids
5 the 2 sperm and tube nucleus are released into synergid
6 one sperm fertilizes egg cell
7 other sperm unites with polar nuclei
8 process is called double fertilization
9 egg (n) and 2 polar nuclei (n & n) -> primary endosperm nucleus (3n)
10 tube nucleus dgenerates
11 remaining synergids and 3 antipodals disintegrate early in development of embryo sac
pollination
transfer of pollen to stigma
what is unique to angiosperms and (Gnetophyta)
double fertilization
what is the process of sperm and polar nuclei fusing called
“triple fusion” because of 3 nuclei are involved
develop of seed and fruit
angiosperm
1 primary endosperm nucleus forms endosperm
2 zygote develops into embryo
3 integuments develop into seed coat
4 ovary wall and related structures develop into fruit
what does endosperm provide embryo and young seedling
food
ecology
study of interaction of organisms with their environment
environment
physical habitat and living (biotic) surrounding of an organism
individual
one organism
population
group of organisms capable of interbreeding among themselves and often sharing a common descent; group of individuals of the same species living at the same time and place
ecosystem
community and abiotic environment that affects it
biosphere
all ecosystems
Earth
ecology of the individual
physiological ecology
how an organism relates to its environment
what is physiological ecology concerned with
evolutionary adaptations that enable individual organisms to meet the challenges posed by their abiotic environment
how is environment variable
terms of light, water, temperature, wind, soil and disturbances
habitat (home)
the location and environmental conditions in which organism lives
what kinds of responses can individuals have to their environment
physiological, anatomical, or behavioral
physiological response
water uptake, photosynthesis
anatomical response
thickness of cuticle, distribution of stomata, sometimes reversible, sometimes not
behavioral response
phenology, growing season and dormancy
acclimation
a physiological change to the environment; occurs within the lifetime of an organism
adaptation
inherited (genetic) characteristics that enhance an organisms ability to survive and reproduce in a particular environment; occurs over many generations (evolutionary change to environment)
what is population ecology concerned with
factors that affect population density and growth
population density
number of individuals per unit area or volume
linear growth
does not limit population size
does not allow new individuals to reproduce
exponential growth
allows new individuals to reproduce
does not limit population size
logistic growth
allows new individuals to reproduce
does limit population size by a carrying capacity (k)
communities
assemblages of populations that live together and interact
what is community ecology concerned with
how interactions between species (predation, competition, and symbioses) affect community structure and organization
descriptors of community
species richness
species diviersity
species richness
number of species present
species diversity
number of species present plus relatives abundances
vegetation
what types of plants are present (important for structuring community and feeding animals)
niche
the role of a species in a community; do not think of niche like “home”; think of it more as a “occupation”
types of interspecific interactions in communities
mutualism
commensalism
predation, grazing, and parasitism
amensalism
competition (-/-)
two or more species both try to obtain a limited resource
more similar niche means more similar resource requirements
lesser competitor is displaced by better competitor
lesser competitor is driven to extinction, can partition resources
predation, parasitism, grazing (+/-)
one organism eats part of or all of another, eating or avoiding being eaten are powerful selective pressures in natural selection
commensalism (+/o)
small orchid on a large tree
plant defense
mechanical spines, thorns, prickles,
chemical- poisons, taste, drugs
animal defense
camouflage, poisonous
ammensalism (-/o)
step on ant, bison trample plants
mutualism (+/+)
2 species work together for mutual benefit, both benefit, sometimes both depend on each other for survival
lichen mutualism
algae and fungus
algae provides energy
fungus protects algae
fungus passes minerals to algae
clark’s nutcracker and white bark pine
rely on each other to survive and reproduce
what is ecosystem ecology concerned with
energy flow and nutrient cycling across communities, and abiotic environment
how does energy flow through the environment
one way
only get 10% of energy at each level going down- trophic pryamid
habitat types
tropical forest desert savanna temperate grassland temperate deciduous forest chaparral coniferous forest tundra polar ice
biome
group of ecosystems similar in type
they contain similar habitats and similar niches for species
general features of terrestrial biomes
often named for major physical or climatic factors and for the predominant vegetation
desert
very high species diversity, near equator, high temp, high percipitation
savanna
grassland with scattered trees, world famous for wild life, high temp, low precipitation
temperate grassland
seasonal drought, occasional fire, grazing by large mammals, world’s most fertile soil, moderate to high temps, low precipitation, fires
temperate deciduous forest
requires more moisture than grasslands or coniferous forests, dormant winter phase, moderate temps, moderate precipitation
chaparral
Mediterranean scrub, middle latitude coastal areas with scrub vegetation, hot dry summer, mild wet winters, frequent fires, moderate temperatures, moderate precipitation, fires
coniferous forest
boreal forest, northern forest, dominated by pines, spruces, firs, usually low in species diversity, moderate temperatures, moderate precipitation,
tiaga
tundra
very cold, absence of tall vegetation, water cannot permeate under lying permafrost, often leads to standing water, low temp, low precipitation
polar ice
extremely cold temps and low precipitation, permanently covered by ice and snow, low temps