Ch 26: The Colonization of Land Flashcards
Some green algae exhibit alternation of generations. All land plants exhibit alternation of generations. No ___________ exhibit alternation of generations.
charophytes
Homoplasies and shared derived traits/ancestral traits are ________ _________.
mutually exclusive
The process of meiosis produces _______ cells.
haploid
These products of meiosis contain one complete set of chromosomes.
Which of the following structures are haploid?
zygote spores sporophyte egg gametophyte
Spores, gametophytes, and eggs.
Spores, which are haploid, grow by mitosis to become haploid gametophytes. The gametophyte produces eggs by mitosis; eggs are also haploid.
The gametophyte is the dominant stage of the life cycle in _____; the sporophyte develops on the body of a gametophyte, where it lives for a briefer time than the gametophyte’s life span.
In ferns, the sporophyte is ________; the gametophyte is tiny and short-lived. Both mosses and ferns have swimming sperm that require moisture to reach an egg.
mosses
dominant
The first fossilized spores that we have are likely ___ million years old.
The first sporophyte tissue appear in the fossil record ___ million years ago.
The first evidence of _________ appear 425 million years ago.
478
450
sporangia
Rhizoids are not ____ _____; they do not take up water, nutrients, or minerals because they are not _________, but they do help to hold the plant in place.
true roots
vascular
Challenges faced by plants moving from water to land: \_\_\_\_\_\_\_\_\_\_ (lack of water) gravity no water currents (for reproduction) UV \_\_\_\_\_\_\_\_\_ nutrient absorption temperature changes more dramatic
desiccation
radiation
The lineage leading to fungi diverged from the lineage leading to plants more than ___ _______ years ago. In contrast, the fungal and animal lineages diverged more recently.
1.2 billion
The fungi are more closely related to ________ than plants.
animals
Fungi are _____________, but they do not ingest food, but rather they secrete digestive enzymes into the environment, and then absorb nutrients after the molecules are broken down.
heterotrophic
Fossilized terrestrial fungi appear in the fossil record > ___ millions years ago.
460
The mushroom is the reproductive structure, the ________ is the feeding structure.
mycelium
What is the term for fungi that form an association which plants?
mycorrhizae
The ___________ are the only present-day algae that share certain distinctive traits with plants, a fact that suggests that they are the closest living relatives of plants.
charophytes
Several adaptations that facilitate survival and reproduction on dry land emerged after plants diverged from their algal relatives. Examples of such traits that are found in plants but not in the charophyte algae include the following:
Alternation of generations. This type of life cycle, consisting of multicellular forms that give rise to each other in turn, is described in Figure 26.6.
Walled spores produced in sporangia. The sporophyte stage of the plant life cycle has multicellular organs called sporangia (singular, sporangium) that produce spores (Figure 26.7). The polymer ____________ makes the walls of these spores resistant to harsh environments, enabling plant spores to be dispersed through dry air without harm.
Apical meristems. Plants also differ from their algal relatives in having apical meristems, localized regions of ____ ________ at the tips of roots and shoots (see Figure 28.16). Apical meristem cells can divide throughout the plant’s life, enabling its roots and shoots to elongate, thus increasing the plant’s exposure to environmental resources.
sporopollenin
cell division
In the case of symbiosis between plants and fungi, note that the fungus goes into the cell wall, but does not pierce the ______ _________.
plasma membrane
In the case of symbiosis between plants and fungi, the fungus benefits by getting _______ _________ (carbohydrates), and the plant gets improved delivery of nutrients (e.g. phosphate).
organic nutrients
Not all fungi make _________.
mushrooms
What advantages did plants have that colonized land?
more sunlight
more CO2
less competition
One of the adaptations of plants to reduce desiccation, was formation of:
dependent embryos, being protected from environment.
Walled spores are resistant to drying – sporopollenin in walls.
Waxy outer coating of the plant called a cuticle, prevents evaporation of water from the surface of the plant into the environment.
cuticle
Sporopollenin is a shared _________ trait of plants, because this feature is present in also in charophytes.
ancestral
Guard cells and stomata
Some non-vascular plants LACK guard cells - stomata are always open.
j
Some non-vascular plants do not have guard cells and their stomata are always open. What is the consequence of this situation?
These plants would be able to live only in damp environments because otherwise they’d lose too much water.
What types of plants lack guard cells?
mosses and liverworts (?)
Vascular tissue allows for long-distance transfer of materials.
xylem – transports water & minerals
phloem – transports sugar, nutrients
d
Adaptations for water and nutrient transport include vascular tissue and roots.
d
Nonvascular plants have root-like structures that anchor them in place, but these are not true roots, and they do not function as efficiently as a true root does.
d
Vascular tissue also provides support, allows plant to grow taller.
Image: xylem cell walls stiffened with a material called ______.
lignin
Taller plants have more access to ________, and are able to spread their spores/seeds farther.
sunlight
Vascular plants have true leaves. Leaves increase the surface area that the plant has. This gives plant more access to sunlight, more surface area for gas exchange.
d
Leaves provide plants an advantage when competing for light because they increase the surface area of the plant that can intercept the light. What is a disadvantage of having high surface area in the leaves?
High surface area increases water loss across the leaves.
The most important adaptation is ______. (?)
Gymnosperms “naked” and “seed” –
Angiosperms are the flowering plants, “angio” means vessel, sperm means “seed”
seeds
Megaspore – female gametophyte
Enclosed in the ovule (from sporophyte)
f
Microspore – male gametophyte = pollen grain, produced by a male cone
f
What are adaptations specific to seed plants?
microscopic gametophytes in seed plants – they are well-protected from desiccation and UV radiation and other threats, deep within the sporophyte tissue.
Why are pollen, ovules, and seeds important?
Pollen is resistant to desiccation, other damage
Ovule: protected in sporophyte, surrounded by integument/ seed coat.
Developing embryo is inside a seed.
kk
Big takeaway for seed plants:
Seed plants are no longer dependent on WATER for reproduction.
ll
Seeds replaced ______ as the main mode of dispersal.
spores
Spores are single-celled
Sporopollenin –> protects, but for a shorter period of time
They lack ______ ____.
stored food
Seeds, in contrast, are _____-______.
Their tough outer covering can help the seed survive for days to years.
They contain stored food.
multi-celled
Arrange the following categories of plants from most inclusive to least inclusive:
- ) embryophytes
- ) green plants
- ) seedless vascular plants
- ) ferns
- ) green plants
- ) embryophytes
- ) seedless vascular plants
- ) ferns
What feature do bryophytes lack?
vascular tissue
Which 3 groups of plants are considered bryophytes (nonvascular plants)?
liverworts
mosses
hornworts
(See Figure 26.18 on p. 538)
What does the term embryophyte encompass?
This is the alternate name for plants that refers to their shared derived trait of multicellular, dependent embryos.
glossary
Seed plants include _______ and _______.
angiosperms and gymnosperms
The term mycorrhizae means ______ ______.
fungus roots
p. 535
Which event in the typical life cycle of sexually reproducing fungi involves transition from a haploid to a diploid stage?
karyogamy
Which taxon is essentially equivalent to the “embryophytes”?
plantae
If a pollen grain germinates (begins growing), it gives rise to a pollen tube that discharges sperm into the female gametophyte within the ovule. Living bryophytes are typically found in moist habitats because they have flagellated sperm that must swim through a film of water to fertilize an egg. The sperm of ferns and all other seedless vascular plants are also flagellated and must swim through a film of water to reach eggs.
In contrast, in _______ and _______ groups, the sperm no longer have to swim to reach the female gametophyte.
gymnosperms and angiosperms
The sexual portion of a fungal life cycle typically occurs in two stages. First, the cytoplasms of two parent mycelia fuse, an event known as _______. Hours, days, or (in some fungi) even centuries may pass between _______ and the next stage in the sexual cycle, karyogamy. During karyogamy, the haploid nuclei contributed by the two parents fuse, producing _______ cells.
plasmogamy
plasmogamy
diploid
Monilophytes are the ferns, horsetails, and whisk ferns. Along with the lycophytes, these make up the _______ ________ _______. The lycophytes include club mosses, spikemosses, and quillworts.
seedless vascular plants
Xylem and phloem are found in the vascular plants, which include lycophytes, ferns, gymnosperms, and angiosperms. Xylem and phloem are the two types of vascular tissue that distinguish all vascular plants from nonvascular plants.
j
Of the major groups of fungi that are recognized by most mycologists, which includes species that produce mushrooms?
Basidiomycetes
In contrast to plants, the cell walls of fungi are composed of ______. This material is identical to the that found in the exoskeleton of arthropods.
chitin
The diploid generation of the plant life cycle always produces _______.
spores
The eggs of seed plants are fertilized within ovules, and the ovules then develop into ______.
seeds
The part of the flower that receives the pollen is the ______.
stigma
Remember, the sticky stigma
During pollination, pollen grains are transferred from the __________ to the __________.
anther
stigma
p. 544
