Final answer:
The four modern-day gymnosperm phyla are Cycadophyta, Ginkgophyta, Coniferophyta, and Gnetophyta, each with distinctive characteristics and representative species such as Sago Palm, Ginkgo biloba, pines and firs, and various Gnetophytes.
Step-by-step explanation:
The four modern-day phyla of gymnosperms are Cycadophyta, Ginkgophyta, Coniferophyta, and Gnetophyta.
- Cycadophyta: This phylum includes gymnosperms like the Sago Palm, which resembles palm trees and is found in tropical climates. Cycads were quite prevalent during the Age of Dinosaurs.
- Ginkgophyta: Ginkgo biloba, which is the only extant species in this phylum, is known for its unique fan-shaped leaves.
- Coniferophyta: This is the most dominant phylum of gymnosperms, encompassing trees like pines, firs, spruces, cedars, and the towering redwoods. These trees are adapted to cold and dry climates, often found in high altitudes and latitudes.
- Gnetophyta: A diverse group that includes plants that produce vessel elements in their wood, making them somewhat closer to angiosperms than the other gymnosperm phyla.