Final answer:
The four modern-day groups of gymnosperms are Coniferophyta (conifers), Cycadophyta (cycads), Ginkgophyta (Ginkgo biloba), and Gnetophyta (gnetophytes). Conifers are the most diverse, cycads thrive in tropical climates, Ginkgo biloba is a singular species resilient to pollution, and gnetophytes share some traits with flowering plants.
Step-by-step explanation:
Diversity of Gymnosperms
The four modern-day groups of gymnosperms are: Coniferophyta (conifers), Cycadophyta (cycads), Ginkgophyta (which includes the sole living species, Ginkgo biloba), and Gnetophyta (gnetophytes). These groups can be described as follows:
- Conifers are the most diverse and widespread group, including trees such as pines, firs, spruces, and redwoods. They are adapted to cold climates with needle-like leaves that reduce water loss.
- Cycads resemble palm trees and are found in tropical regions. They have large, compound leaves and produce cones.
- Ginkgo biloba, the only species in Ginkgophyta, has fan-shaped leaves and is known for its resilience to urban pollution.
- Gnetophytes are a varied group that shares some characteristics with flowering plants, such as the presence of vessel elements in their wood.
Gymnosperms are seed plants that do not produce flowers or fruits, and their seeds are usually found in cones. Modern gymnosperms emerged in the Carboniferous period and were the dominant plant life during the Mesozoic era.