Call Now
1800-102-2727We live in a beautiful world surrounded by lots of organisms. Big animals are always fascinating and interesting to see, right?. The biggest animal existing now on the Earth is the blue whale and the one which is on the land is the elephant. We can not see these animals more often. But we might have seen the habitats and behaviour of these animals at least in televisions. Do you remember another biggest animal which became extinct? Yes, the dinosaurs!! They used to live during the Mesozoic era that includes three geologic time periods; Triassic, Jurassic and Cretaceous periods. Different species of dinosaurs lived during these periods. But the extinction of the last dinosaur happened during the Cretaceous period.
If you ever watched the Jurassic World movie, which depicts the life of dinosaurs, you might have observed their habitats too. What type of trees and plants can you observe around them? You can never find any trees like teak or gulmohar or plants like roses or bamboo, because these categories of plants are angiosperms. Do you know the reason for this? Why were angiosperms not present during the time of dinosaurs? The reason for this can be explained through the evolution of plants. Angiosperms started to evolve and became dominant during the Cretaceous period. This is the period where the dinosaurs began to go extinct.
So during the triassic and jurassic period, which kind of plants were abundant? Just think about the plants which we can see around the dinosaurs. What are they? We can mostly see the plants like Pinus, Cycas etc. right? These plants are included in the group called gymnosperms, which were dominant in the Triassic and Jurassic periods.
Fig: Dinosaurs and their habitat
So now it's clear that angiosperms evolved after gymnosperms and because of this there will be many similarities and dissimilarities between these two plant groups. In this article we are going to discuss more about the differences between gymnosperms and angiosperms.
Table of contents
The simple and primitive seed bearing plants without flowers are called gymnosperms. The Greek word ‘gymnos’ means naked and ‘sperma’ means seed. Hence gymnosperms are naked seed bearing plants. Their ovules are naked and their seeds are not enclosed in the ovary. So they are often described as phanerogams without ovaries. They are the most ancient group of seed bearing plants and they emerged during the Palaeozoic era. Around 70 genera and 900 species of gymnosperms are distributed in the tropical and temperate regions.
Fig: Gymnosperms
Some of the major general characteristics of gymnosperms are as follows:
Fig: Tap root of Pinus
Fig: Symbiotic relationship in gymnosperm roots
Fig: Types of stems in gymnosperms
Fig: Male and female cone
Fig: Monoecious and dioecious gymnosperms
Fig: Life cycle of gymnosperms
Gymnosperms can be classified into four classes and they are as follows along with their examples:
Fig: Cycadophyta
Fig: Ginkgo
Fig: Coniferophyta
Fig: Gnetum
The seed bearing plants with the flowers are called angiosperms. The Greek word ‘angion’ means vessel and ‘sperma’ means seeds. Hence the angiosperms are the plants in which the seeds are covered by fruits. In them the pollen grains and ovules are developed in specialised structures called flowers. Before fertilisation, the ovules remain enclosed by the ovary. It is the same for the seeds after fertilisation in them. So they are phanerogams with ovaries. Angiosperms are the most advanced group of plants. They emerged during the late Permian period. They are the largest and diverse group of the Plant Kingdom with 300,000 species. 80 percent of all living green plants are included in the angiosperms.
GIF: Blooming of flowers in angiosperm plants
Some of the major general characteristics of angiosperms are as follows:
Fig: Smallest and largest flower
GIF: Germination of seeds in dicotyledons and monocotyledons
GIF: Pollination by biotic agents
Fig: Different types of pollen grains
GIF: Pollen tube formation
GIF: Double fertilisation in angiosperms
Fig: Life cycle of angiosperms
On the basis of the number of cotyledons, angiosperms can be divided into two classes as follows:
Dicotyledonae - Mango tree, Hibiscus, teak, rose etc.
Fig: Dicotyledons
Monocotyledons - Coconut tree, palm, bamboo, sugarcane etc.
Fig: Monocotyledons
The major difference between gymnosperms and angiosperms are as follows:
Gymnosperms |
Angiosperms |
It is the largest and most diverse group in the Plant Kingdom |
It is the smaller and more ancient group in the Plant Kingdom |
Variety of plant body types present here, ranging from annual herbs and climbing vines to massive trees |
Mostly large woody trees and shrubs present in this group. The only gymnosperm genus with climbing vines is the Gnetum. |
They possess scale like or needle like leaves |
They possess flat leaves |
Stem is soft wood type |
Stem is hard wood type |
Mostly taproot system present |
Taproot and fibrous root system are present |
Woody sporophylls present in them which aggregates to form cones |
Delicate sporophylls present in them aggregate to form flowers |
Cones does not have sepals and petals |
A flower has sepals and petals |
Cones are generally unisexual, bisexual cones are present in Gnetales (Ephedra, Gnetum and Welwitschia) |
Flowers can be unisexual or bisexual |
Cones have elongated central axis |
They have small and disc shaped thalamus |
Microsporophylls are broad and not distinguished into filament and anther |
Microsporophyll consists of filament and anther |
Each microsporophyll has two to many microsporangia |
Four microsporangia or pollen sacs are present in each anther |
Megasporophyll does not have stigma, style and ovary |
Megasporophyll have stigma, style and ovary |
Megasporophylls are woody and unrolled |
Megasporophylls are delicate and rolled to form flowers |
Placenta is absent |
Placenta is present |
Ovules are exposed on megasporophylls |
Ovules are placed inside the ovary |
Ovule is covered by a three layered integument |
Ovule is covered by one or two thin integuments |
Micropyle is wide |
Micropyle is small |
Pollen grains directly reach the exposed ovules during pollination |
Pollen grains reach the stigma during pollination |
Pollination is mainly through wind (anemophily) |
Pollination can be through wind (anemophily), water (hydrophily), insects (entomophily), animals (zoophily) etc. |
Female gametophyte is large and parenchymatous |
Female gametophyte is represented by a seven celled eight nucleated embryosac |
One pollen fuses with one egg and no double fertilisation present |
Double fertilisation takes place here |
Endosperm formation occurs before pollination |
Endosperm formation occurs after fertilisation |
Haploid endosperm present |
Triploid endosperm present |
Seeds usually formed in unisexual cones, known as strobili |
The seeds develop in the ovaries of flowers |
Seeds are not protected by a fruit |
Seeds are surrounded by a protective fruit |
Xylem vessels are absent exception is shown by Gnetum which has vessels |
Xylem vessels are present for conduction |
Phloem components include sieve cells, albuminous cells, phloem parenchyma, and phloem fibres |
Phloem components include sieve tube elements, companion cells, phloem fibres and phloem parenchyma |
Examples include Cycas, Zamia, Williamsonia, Lepidopteris, Ginkgo, Trichopitys, Pinus, Abies, Cupressus, Gnetum, Ephedra, Welwitschia etc. |
Examples include Mango tree, Hibiscus, teak, roses, Coconut tree, palm, bamboo, sugarcane etc. |
Fig: Gymnosperms |
Fig: Angiosperms |
1. The major difference between gymnosperms and angiosperms is
Solution: The simple and primitive seed bearing plants without flowers are called gymnosperms. The Greek word ‘gymnos’ means naked and ‘sperma’ means seed. Hence gymnosperms are naked seeded plants. Their ovules are naked and their seeds are not enclosed in the ovary. So they are often described as phanerogams without ovaries. The seed bearing plants with the flowers are called angiosperms. The Greek word ‘angion’ means vessel and ‘sperma’ means seeds. Hence the angiosperms are the plants in which the pollen grains and ovules are developed in specialised structures called flowers. Before fertilisation, the ovules remain enclosed by the ovary. It is the same for the seeds after fertilisation in them. So they are phanerogams with ovaries. Hence the correct option is a.
2. Find out the structure which is not a haploid structure in angiosperms?
Solution: Double fertilisation is a unique feature of angiosperms. The fusion of one of the male gamete (n) and the female gamete or egg (n) results in the formation of zygote (2n). This is known as syngamy. Zygote gradually develops into an embryo. The other male gamete (n) fuses with a central cell having two polar nuclei (2n) and forms a triploid primary endosperm (3n) cell with primary endosperm nucleus or PEN, which later forms the endosperm. This is known as triple fusion. Double fertilisation is the combination of syngamy and triple fusion. Embryo sac is the female gametophyte in angiosperms. It is formed from the haploid megaspore. Hence all the cells inside the embryo sac are haploid and it is a seven celled and eight nucleated structure. It comprises three antipodals (n), two synergids (n), one egg cell (n) and one large central cell with two polar nuclei (n). Hence the correct option is b.
3. Find out the correct statement?
Solution: Megasporangia in megasporophyll and microsporangia in microsporophyll are seen in gymnosperms. They produce two kinds of spores such as microspores and megaspores respectively and hence gymnosperms are heterosporous. Microspores develop into male gametophytes and megaspores develop into female gametophytes. Only a few pteridophytes show the heterosporous condition, such as Selaginella and Salvinia. Hence the correct option is b.
4. Which of the following plants shows symbiotic association in roots?
Solution: The roots of Pinus show fungal association. These roots are called mycorrhiza. Fungi help to absorb water and minerals like phosphorus for the plant and the plant, in turn, provides nourishment. Mutualism or symbiosis is the term for this type of beneficial association. A symbiotic association with blue green algae is shown by the coralloid roots of Cycas. The blue green algae help in nitrogen fixation. Cyanobacteria grow on the Cycas. The leguminous plants such as Pisum sativum share a symbiotic relationship with bacterium Rhizobium leguminosarum. It helps in the fixation of atmospheric nitrogen into nitrates. These nitrates can be absorbed by the roots of the legumes. Hence the correct option is d.
1. What are the xerophytic adaptations of the leaflets of Cycas?
Answer: The leaflets in the Cycas are termed as pinnules. Some of the xerophytic adaptations of Cycas leaflets are as follows:
Fig: Leaflets in the Cycas
2. Why are cycads called living fossils?
Answer: Cycads are the ancient group of tropical plants that can produce cones. Since they have existed for more than 200 million years ago they are called living fossils. This period existed even before the time of dinosaurs. They were abundant during the Triassic and Jurassic periods. They survived the mass extinctions, ice ages, continental drifts and other challenges. But they are in great trouble today.
Fig: Cycas
3. What was the first flower formed?
Answer: The flowers of Archaefructus an extinct genus of herbaceous aquatic seed plants are considered as the first flower. This ancient plant was found in Liaoning, which is a coastal province in Northeast China. The flowers of Archaefructus were small, simple and this plant is considered as one of the first flowering plants. These plants lived around 130 million years ago and they grew in water or near the water.
4. What is the APG system of classification?
Answer: The first version of a modern and molecular based system of plant taxonomy is the APG system or angiosperm phylogeny system of plant classification. It was published in 1998 by the angiosperm phylogeny group. 462 families and 40 orders are recognised by the APG system of classification.
YOUTUBE LINK: https://www.youtube.com/watch?v=xSq5NU5Wn_U
https://www.youtube.com/watch?v=cucmmMpuKZc&t=2895s