1. Mosses, Ferns, Conifers, and Flowering Plants
Plant Life Cycles
Mosses, Ferns, Conifers, and Flowering Plants

2. General Life Cycle of Plants
Recall that all plants cycle between two phases during their life
Called ‘alternation of generations’
The two generations are gametophytes and sporophytes

3. Life Cycles of Seed Plants
Seed plants evolved after mosses and ferns
They have efficient vascular systems and seeds to nourish offspring
Gymnosperms = mostly pine trees; use cones for reproduction
Angiosperms = flowering plants; use flowers to attract pollinators

4. Gymnosperm Life Cycle
In pine trees, the mature tree is the sporophyte (diploid)
The tree makes two cone types: the male pollen cone and female seed cone
Pollen cones make the male gametophyte: pollen

5. Gymnosperm Life Cycle
The seed cone produces the female gametophyte, which produces thousands of eggs
At the base of each cone scale,
there are two ovules where the
gametophyte develops
The gametophyte
and pollen are
haploid
Ovules developing gametophytes

6. Gymnosperm Life Cycle
Wind carries pollen to the female cones, where fertilization occurs
Fertilization creates a young, diploid sporophyte on the cone scale
Once the cone drops, the sporophyte develops into a mature plant

7. Angiosperm Life Cycle
In flowering plants, the sporophyte is the mature plant we see
The sporophyte produces flowers, complete with anthers and an ovary
Anthers create pollen, the male gametophyte

8. Angiosperm Life Cycle
The female gametophyte develops in the ovule (eggs) of the flower
Pollen lands on the stigma, travels down the style, and fertilizes the ovule
The fertilized egg is now diploid, and is packaged into a seed
The seed is surrounded by a fleshy ovary called ‘fruit’

9. Angiosperm Life Cycle
When the fruit falls to the ground, the seed can grow into a seedling, a new, diploid sporophyte

10. Fruit Development
Once fertilization occurs, flower petals die off and nutrients are rushed to the seed
Parts of the ovule toughen to form a seed coat
The ovary containing the ovules forms a tough skin and swells with sugary tissue
Fruit = a seed enclosed in an ovary

11. Types of Fruit
Simple fruit = development of large ovary from one pistil
Aggregate fruit = development of small ovaries from multiple pistils on one flower
Multiple fruit = development of ovaries from many flowers that fuse together to form one mass

12. Aggregate Fruits
Simple Fruits
Multiple Fruits

13. What’s a Bulb? A bulb is NOT a fruit or seed
A bulb is an entire plant, resting dormant underground
Bulbs contain precursors to root,
shoot, and leaf systems that will
mature when conditions are right
Perennial monocots typically
utilize bulbs

14. Life Cycles Review!
Complete the Coloring Activity for Gymnosperm and Angiosperms
As a class, we will go outside and collect one piece of evidence of each life cycle (moss, fern, gymnosperm, angiosperm)
Inside, you will identify the pieces of evidence and explain all four life cycles to a partner