November 21, 2017

Biology: Angiosperms

An angiosperm is a plant that produces seeds that are enclosed in a fruit.
Ovary is where seeds develop, it is located within an angiosperm's flower - the reproductive structure.
Two characteristics of angiosperms are that they produce flowers and fruits.
Angiosperms live almost everywhere on Earth.

The Structure of Flowers

Source: Pearson Education
All flowers have the same function - reproduction.
When a flower is still a bud, it is enclosed by leaflike structures called sepals. Sepals protect the developing flower. After the sepals fold back, the petals are revealed.
Within the petals are the flower's male and female reproductive parts.


The stamens are the male reproductive parts. The thin stalk is called the filament. Pollen is produced in the knob, or anther, at the top of the stalk.


The pistils are the female parts which are usually found in the center of the flower. The sticky tip of the pistil is called stigma. A slender tube, called a style, connects the stigma to a hollow structure at the base of the flower. This hollow structure is the ovary, which contains one or more ovules.


Source: askIItians
First, pollen falls on a stigma. In time, the sperm cell and egg cell join together in the flower's ovule. The zygote develops into the embryo part of the seed.

Types of Angiosperms

Source: Wikipedia
Angiosperms are divided into two major groups: monocots and dicots.


The flowers of a monocot usually have either three petals or a multiple of three petals. Monocots usually have long, slender leaves with veins that run parallel to one another. The bundles of vascular tissue in manocot stems are usually scattered randomly throughout the stem.


The flowers of dicots often have either four or five petals or multiples of these numbers. The leaves are usually wide, with veins that branch off from one another. Dicot stems usually have bundles of vascular tissue arranged in a circle.

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