30 Questions
What characteristic of seedless vascular plants allows them to grow taller than bryophytes?
Vascular tissue
What is the primary reason why plants with lignified vascular tissue had an evolutionary advantage?
Access to sunlight and spore dispersal
What type of leaves do all lycophytes have?
Microphylls
What is the likely origin of true roots in vascular plants?
Subterranean stems
What is the trend among plants in terms of life cycles?
Increasing dominance of sporophytes
What is the characteristic of ferns that is reminiscent of ancestral cycads?
Circinate vernation
What is the function of the pollen tube in the fertilization process?
To dig through the megasporangium and reach the ovule
What is the significance of the heat from natural wildfires in seed dispersal?
It loosens the structure of the cones to disperse seeds
What characteristic of gymnosperms made them better adapted to arid climates?
Their thick cuticles and needle-like leaves
What is the earliest evidence of seed plants dated to?
360 million years ago
What was the dominant species at the end of the Cretaceous period?
Angiosperms
What type of tree had a woody stem but did not bear seeds?
Archaeopteris
What is the primary advantage of using transgenic organisms in agriculture?
Increasing world food supply without expanding farmlands
What is the function of the Bt toxin in genetically engineered crops?
To produce a toxin that is deadly to insects but harmless to vertebrates
What is the primary concern regarding the use of glyphosate-resistant crops?
They lead to the development of glyphosate-resistant weeds
What is the purpose of genetically engineered 'Golden Rice'?
To address vitamin A deficiencies in poor communities
What is the definition of biomass in the context of biofuels?
The total mass of organic matter in a group of organisms in a particular habitat
What is the potential negative effect of glyphosate on human and livestock health?
It can interfere with beneficial gut bacteria
What is the characteristic feature of the male gametophytes of cycads?
They are elongated cones
Which of the following gymnosperms can thrive in air-polluted environments?
Ginkgophyta
Which gymnosperm phylum is characterized by the presence of vessel elements in some of its species?
Gnetophyta
Which of the following is NOT a characteristic of conifers?
They are deciduous trees
What is the term for the 'fruits' of Ginkgo biloba?
Arils
Which of the following is an example of a living fossil?
Wollemi pine
What is the primary function of fruits in angiosperms?
To protect seeds and aid in their dispersal
What is the estimated time period when angiosperms originated and diversified?
20-30 million years ago
What is the characteristic of the earliest known angiosperm fossil, Archaefructus?
It was a herbaceous and aquatic plant
What is the estimated time of divergence between angiosperms and gymnosperms?
305 million years ago
Which of the following is NOT a characteristic of flowers in angiosperms?
Ability to synthesize nutrients and energy
What is the location where some of the earliest extant angiosperms, such as Amborella trichopoda, can be found?
New Caledonia
Study Notes
Flower and Fruit Adaptations
- Flowers are variable in shape, size, color, odor, and symmetry.
- Fruits are formed when the ovary wall thickens and matures, protecting seeds and aiding in their dispersal.
- Mature fruits can be either fleshy or dry.
- Various fruit adaptations help disperse seeds by wind, water, or animals to new locations.
Angiosperm Evolution
- Angiosperms originated during the Cretaceous period, around 140 million years ago, and diversified over a 20-30 million year period.
- The earliest pollen fossils with angiosperm characteristics are 130 million years old.
- The earliest angiosperm fossil, Archaefructus, was herbaceous and aquatic.
Angiosperm Phylogeny
- Angiosperms and gymnosperms diverged 305 million years ago.
- Amborella trichopoda, water lilies, and star anise are some of the earliest extant angiosperms.
Ferns and Seedless Vascular Plants
- Ferns were the first plants to grow tall.
- Seedless vascular plants have flagellated sperm and are restricted to moist environments.
- They have vascular tissue that allows them to transport water to greater heights, enabling them to grow taller.
Origins and Traits of Vascular Plants
- Living vascular plants are characterized by life cycles with dominant sporophytes.
- They have transport mechanisms in xylem and phloem.
- They have well-developed roots and leaves.
- Roots anchor the plant in soil and allow the shoot system to grow taller.
Early Seed Plants and the Rise of Gymnosperms
- Characteristics of seed plants are found in the late Devonian period, 380 million years ago.
- A fossil of the genus Elkinsia from 360 million years ago provides the earliest evidence of seed plants.
- Gymnosperms are better adapted to arid climates due to having thick cuticles and needle-like leaves that reduce surface area.
Angiosperms and Gymnosperms
- Angiosperms only began to replace gymnosperms as the dominant species at the end of the Cretaceous period.
Transgenic Organisms and Biotechnology
- Transgenic organisms have been engineered to express a gene from another species.
- Pros of transgenic organisms include reducing world hunger and malnutrition, and reducing fossil fuel dependency.
Gymnosperm Diversity
- Cycadophyta (cycads) have large cones, palm-like leaves, and flagellated sperm.
- Ginkgophyta (Ginkgo biloba) has flagellated sperm and a high tolerance to air pollution.
- Gnetophyta (three genera: Gnetum, Ephedra, Welwitschia) have some species that are tropical, while others live in deserts.
- Coniferophyta (conifers) have woody cones, and most species have needle-like leaves.
Learn about the pros and cons of transgenic organisms in agriculture, including their potential to increase food supply and reduce pesticide use.
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