Which of the following adaptations is common to all seed plants?
reduced gametophytes heterospory pollen ovules all of the above
Which one of the following is true of seed plants, but not true of seedless plants?
The gametophyte is reduced and dependent on the sporophyte.
The diploid generation of the plant life cycle always _____.
The closest seedless relatives of seed plants produce one kind of spore that gives rise to a bisexual gametophyte. What does this suggest about the ancestors of seed plants?
They were homosporous.
The eggs of seed plants are fertilized within ovules, and the ovules then develop into _____.
The cells within pollen grains are _____ and together comprise the _____.
haploid; male gametophyte
Which example below is evidence provided by living gymnosperms of an evolutionary transition between seedless and seed plants?
The sperm of some gymnosperms have flagella.
Seeds have advantages over spores. For example, _____.
seeds contain embryonic plants, an abundant food supply, and a protective covering
Which gymnosperm phylum below is characterized by large cones and fern-like leaves and thrived during the Mesozoic?
Dietary supplements and decongestants containing ephedrine have recently become more strongly regulated in the United States. Ephedrine is an extract of a plant belonging to which phylum?
What significant change occurred on Earth between the Carboniferous period and the Permian that most likely contributed to the success of the gymnosperms?
The climate became drier and warmer.
What is located in the scalelike structures packed densely in pollen cones?
Each pollen grain of a gymnosperm contains a _____.
In ovulate cones megasporocytes undergo _______ and produce ______ megaspores.
In a typical conifer, how long does it take for fertilization to occur after pollination?
Which types of angiosperms would most likely be wind-pollinated rather than animal-pollinated?
The first and second answers are correct.
Like gymnosperms, many grasses and angiosperm trees are wind-pollinated. To conserve energy, these angiosperms do not produce complete flowers (complete flowers have all four of the basic parts). Which part would be unnecessary for wind-pollinated angiosperms?
The portion of a flower that receives the pollen is the _____.
During pollination, pollen grains are transferred from the _____ to the _____.
A pea pod is formed from _____. A pea inside the pod is formed from _____.
an ovary; an ovule
After fertilization, the _____ develops into a seed and the _____ develops into a fruit.
Which one of the following best describes the function of fruits?
protection and dispersal of seeds
A plant is said to be cross-pollinated if _____.
pollen grains are transferred to a flower on a different plant
The pollen tube releases two sperm cells into the embryo sac. The result of this is the _____.
union of one sperm nucleus with the egg nucleus while the other sperm nucleus unites with two nuclei of another megagametophyte cell, forming a triploid nucleus
Of the following, which is a difference in how reproduction occurs in gymnosperms compared to angiosperms?
Only the sperm of angiosperms combine with megagametophyte nuclei to form triploid endosperm.
The triploid nucleus of the embryo sac develops into the _____.
In gymnosperms, the seed coat develops from the integument. In angiosperms, the seed coat develops from the _____.
The vast majority of angiosperms with two cotyledons formerly classified as _____ are now classified as _____.
Which of the following characterizes eudicots?
two cotyledons, netlike veins, taproot usually present
A bright pink flower with deep floral tubes will most likely be pollinated by which mechanism?
birds with long beaks
Six major crops-wheat, rice, maize, potatoes, cassava, and sweet potatoes-constitute what percentage of all the calories consumed by humans?
At current rates of deforestation, tropical rain forests will be eliminated in _____ years.
Besides the plant tissue that humans ingest, which angiosperm tissue is most directly important for human survival?