The basis of reproductive strategies is the survival of plant in particular habitat. These reproductive strategies are developed by natural selection. Every organism reproduces to maintain their specie. Each organism waanted that most of its offering survive in the next generation. .Therefore. the adapt different reproductive strategics. Reproduction ma lie asexual •tr sexual. Different organisms have different reproductive strategies. For example
- Some species of oak does not reproduce until it becomes 20 year old. Then it produces large number of seeds each year.
- Annual desert wildflowers produce many small seeds and then die. The reproductive strategies depend on three factors:
- Clutch size
The number of offspring or seeds produced at each reproductive cycle by a plant is called clutch size. For example, a plant produces 1000 seeds in its one season. It is its clutch size. Generally plants which large clutch size (produce large number of seeds) produce small seeds or fruits. Their seeds and fruits have small amount of stored energy. Wheat
- produces a large number of small seed. The plants which have small clutch produce larger seeds and fruits like mangoes.
- Number of reproductive cycle per lifetime
There are two types of plants:
(a) Some plants show few reproductive cycles in their life time. Such plants use most of their stored energy for growth and maintenance function. They grow well and they have large size. For example, the cones of the pines mature in three years. So it has less number of reproductive cycles in its life time but it has large size. Some annual plants reproduce only once during their life time.
(b) Other plants reproduce many- a times during their life time. They divided their energy budget for growth, maintenance and reproductive. These plants generally have small size.
- Age at first reproduction
Age of first reproduction has great effect on the age of plant. Generally. annual plants start reproductive very early. So they have very life span of only one season. On the other hand, the plants which start reproduction late have long life span. For example most of mangoes start reproduction at the age of five to 10 years. So it has long life span.
Types of life cycles on the basis of reproductive strategies
There are two types of plants on the basis of reproductive strategy:
I. Opportunistic life cycle: In this case, the plants produce large number of seeds in a single reproductive cycle. They store small amount of food in their seed. Survivorship is generally low in these species. The population site of these plains fluctuates rapidly. When environmental conditions are its (nimble. large number of seed grows and size of population greatly increased. When conditions are unfavourable, only few seeds are able to grow. Thus size of the population remains small. Most of the annual plants like dandelion show opportunistic life cycle.
2. Equilibria] life cycle: In this case, the plants produce small number of seed in single season. They have large amount of stored food in seed. Most of these seeds grow to form plants. Their populations do not fluctuate rapidly. Most of the annual plants like coconut palm show this type of life cycle.