Gymnosperms & Angiosperms
What kind of relationship do angiosperms have with animals?
Coevolutionary, especially insect pollinators
Why do scientists think Amborella sits at the base of the angiosperm phylogenetic tree?
Comparative analysis of its genome shows it diverged earlier than other angiosperms
What clad is used for nasal decongestants?
Gnetophytes
What gymnosperm clad shows morphological characteristics with early angiosperms?
Gnetophytes
Which evolved first, gymnosperms or angiosperms?
Gymnosperms
After fertilization, where does the second (triploid) zygote develop?
Into the nutritive endosperm of the seed.
What happens to the diploid megasporocyte in reproduction?
It divides by meiosis to produce four haploid megaspores, only one of which survives.
What does "dioecious" mean and which clad does it pertain to within the gymnosperms?
It means both male and female plants are produced. Cones produce pollen in male plants and ovules in female plants. The clad Cycads are dioecious.
What is a cotyledon?
an embryonic leaf
After fertilization, where does the first zygote develop?
Into the embryo
What are some interesting factors when it comes to pollination?
-Pollinating insects often cue in on ultraviolet colors -Deceptive pollination -Pollination by entrapment
What are the four kinds of gymnosperms?
1. Cycads 2. Ginkgo 3. Gnetophytes 4. Conifers
What three adaptations do angiosperms have?
1. Enclosed seeds 2. More efficient vascular system 3. Nutrient storage capacity
What are the five major differences of monocots and dicots? (compare and contrast)
1. Monocots have one cotyledon, dicots have two. 2. Monocots have floral parts in threes, dicots have floral parts in fours or fives 3. Monocots have parallel leaf veins, dicots have netlike leaf veins 4. Monocot's pollen grain has one pore or furrow, dicot's pollen grain has three pores or furrows 5. Monocots vascular bundles throughout stem's ground tissue, dicots stem's vascular bundles arranged in a ring
What are the two main groups of angiosperms? (give examples)
1. Monocots: grasses, palms, onion family, lily family, orchids, etc. 2. Dicots: broadleaf plants, most trees and shrubs, daisy family
Explain briefly double fertilization.
1. One sperm fertilizes egg to make DIPLOID zygote 2. Another sperm fertilizes a diploid cell to make TRIPLOID endosperm
In adaptation to these dry environments, what three adaptations did gymnosperms produce?
1. Pollen and ovules encapsulate entire male and female gametophyte, respectively. -- Water required for reproduction eliminated-- 2. Seeds provide protective coating and resources for developing embryo 3. Bark surrounding the stem, allowing water retention and protection against enemies
The most recent evidence supports the classification of angiosperms as ________.
A sister group to the gymnosperm clade
What is the female reproductive organ called of an angiosperm flower?
Carpel
What parts does a seed consist of?
An embryo with a protective covering (seed coat) and food for early growth (endosperm)
What is different about angiosperms life cycle than gymnosperms?
Angiosperms have double fertilization
Which of the following adaptations gave gymnosperms a selective advantage over the nonvascular and seedless vascular plants during the Permian period?
Bark, seeds, needle-shaped leaves, greatly reduced gametophyte stage
What features of the genus Gnetum led to the now-discounted hypothesis that they were primitive angiosperms?
Broad leaves and flower-like structures.
How does the angiosperm flower provide a selective advantage over the gymnosperm cone?
By producing nectar as a reward for animal pollinators
Which is the largest and most diverse group of existing gymnosperms?
Conifers
All land plant's life cycle alternates between a _____ sporophyte generation and a ______ gametophyte generation.
Diploid; haploid
What type of environment do gymnosperms thrive in?
Dry
What part of the angiosperm seed is developed from a triploid nucleus that is starchy and serves as nourishment for the embryo?
Endosperm
What are some examples of gnetophytes?
Ephedra....broad leaves and flower like structure
What best describes the formation of multiple fruits?
Form from clusters of separate, individual flowers
What is the only surviving ginkgo?
Ginkgo biloba
What kinds of animals pollinate angiosperms?
Insects, bats, birds and lizards
How did the adaptation of needle-shaped leaves help conifers thrive and diversity in arid land environments?
Needle shaped leaves help conifers thrive and diversity under dry conditions because they minimize surface area and therefore also minimize transpiration
A single diploid megasporocyte exists in the _____?
Ovule
Define how plants evolved and how we classify them.
Plant evolution involved a smaller and smaller gametophyte, completely enclosed by the sporophyte. Also, the male and female spores and gametophytes became distinct--males were small (microspores, microgametophyte), females bigger (megaspore, megagameophyte)
What type of mutualistic relationship do angiosperms have with animals?
Pollen and nectar rewards
What structure of a pine is the immature male gametophyte?
Pollen grain
What function does a fruit perform?
Protect developing seeds
Passive and active are two different types of what?
Seed dispersal. Passive - wind, water Active - animal consumption
At what stage of alteration of generations in a zygote present?
Sporophyte, diploid
What is the male reproductive organ called of an angiosperm flower?
Stamen
What parts do a female's carpel consist of?
Stigma, style, ovary and ovule
Where is the ovary of an angiosperm flower located?
The base of a flower
What environmental change led to reduced rainfall and fluctuating temperatures?
The coming together of Pangea. This provided environmental conditions favoring gymnosperms, allowing them to flourish.
Why is a tomato considered a fruit (in botanical language) while the fleshy part of an apple is not?
The fleshy part of an apple grows from the receptacle, but fruits such as a tomato grow from the ovary
Where did the very first seed occur on?
The now extinct plants called "seed ferns"
Explain the first step of pollination of an ovule.
The pollen grain pollinated the female parts of the flower by landing on the stigma. Here, the pollen grain germinates, and a pollen tube grows down the style until it meets the female gametophyte.
What does the female megagametophyte consist of?
The surviving megaspore divides by mitosis to produce 7 haploid cells. One large, centrally located cell contains two nuclei, called polar nuclei. Another cell is the egg. The seven-celled structure makes up the female gametophyte, called the megagametophyte.
What is the most common function of angiosperm's sepals?
They protect the petals and other organs during flower development
Which is true of the earliest fossil angiosperms?
They were aquatic and terrestrial
What trait has not contributed to the dominance of angiosperms in many ecosystems?
Thick, desiccation-resistant leaves that persist year-round in temperate habitats
For what purpose did seeds evolve?
To allow dispersal and dormancy until times were right for growth.
How many types of spores do angiosperms produce?
Two
Explain the second step of pollination of an ovule.
Two sperm from the pollen grain travel through the pollen tube and enter the female gametophyte. One fertilizes the egg, forming a diploid zygote. The other fertilizes two polar nuclei, forming a triploid cell. This is called double fertilization.
By what mechanism is most gymnosperm pollen carried from male pollen cones to the female ovule cones that contain the eggs?
Wind
What are some examples of cycads?
resemble palms and ferns