<< Chapter < Page Chapter >> Page >
By the end of this section, you will be able to:
  • Explain why angiosperms are the dominant form of plant life in most terrestrial ecosystems
  • Describe the main parts of a flower and their purpose
  • Detail the life cycle of an angiosperm
  • Discuss the two main groups of flowering plants

From their humble and still obscure beginning during the early Jurassic period, the angiosperms—or flowering plants—have evolved to dominate most terrestrial ecosystems ( [link] ). With more than 250,000 species, the angiosperm phylum (Anthophyta) is second only to insects in terms of diversification.

 Photo shows a winding pathway bordered by flowers in a variety of colors and shapes.
These flowers grow in a botanical garden border in Bellevue, WA. Flowering plants dominate terrestrial landscapes. The vivid colors of flowers are an adaptation to pollination by animals such as insects and birds. (credit: Myriam Feldman)

The success of angiosperms is due to two novel reproductive structures: flowers and fruit. The function of the flower is to ensure pollination. Flowers also provide protection for the ovule and developing embryo inside a receptacle. The function of the fruit is seed dispersal. They also protect the developing seed. Different fruit structures or tissues on fruit—such as sweet flesh, wings, parachutes, or spines that grab—reflect the dispersal strategies that help spread seeds.

Flowers

Flowers are modified leaves, or sporophylls, organized around a central stalk. Although they vary greatly in appearance, all flowers contain the same structures: sepals, petals, carpels, and stamens. The peduncle attaches the flower to the plant. A whorl of sepals (collectively called the calyx    ) is located at the base of the peduncle and encloses the unopened floral bud. Sepals are usually photosynthetic organs, although there are some exceptions. For example, the corolla in lilies and tulips consists of three sepals and three petals that look virtually identical. Petals , collectively the corolla    , are located inside the whorl of sepals and often display vivid colors to attract pollinators. Flowers pollinated by wind are usually small, feathery, and visually inconspicuous. Sepals and petals together form the perianth    . The sexual organs (carpels and stamens) are located at the center of the flower.

As illustrated in [link] , styles, stigmas, and ovules constitute the female organ: the gynoecium    or carpel    . Flower structure is very diverse, and carpels may be singular, multiple, or fused. Multiple fused carpels comprise a pistil    . The megaspores and the female gametophytes are produced and protected by the thick tissues of the carpel. A long, thin structure called a style    leads from the sticky stigma    , where pollen is deposited, to the ovary    , enclosed in the carpel. The ovary houses one or more ovules, each of which will develop into a seed upon fertilization. The male reproductive organs, the stamens (collectively called the androecium), surround the central carpel. Stamens are composed of a thin stalk called a filament    and a sac-like structure called the anther. The filament supports the anther    , where the microspores are produced by meiosis and develop into pollen grains.

Questions & Answers

what is a specicide
Twinkl Reply
why are mosquitoes primary and secondary consumers
Twinkl
what are the structures found in all viruses
Twinkl
how does vaccinating a woman prevent her baby from getting the illness?
Twinkl
how does selective breeding increase crop size
Twinkl
wat is an animal cell
Monicah Reply
what is deer
Khansawu Reply
breathing in reptiles
sam Reply
which molecules binds to the active site of an enzyme
Ghulam Reply
human
Haggai
what is nutrients
Patrick Reply
nutrients is substance which body use in terms of need
Haggai
yes..
Abdullahi
can I join?
Osei
substance that provides nourishment essential for the maintenance of life and for growth.
umar
right same answer as you Umar
Namuli
please remind me
Namuli
Any material that provide essential components for cell metabolisms is nutrient
Mahmood
what are the types of skeleton
Tanyi Reply
endo skeleton and exo skeleton
Faith
or types of skeletons There is exo skeleton found in class insecta Exo skeleton found in phylum chordata and lastly hydrostatic skeleton found mainly in earth worms
Daniel
and hydrostatic skeleton
Godbless
bronah
Kapoko
endo, exo and hydrostatic skeleton
Mico
what is life?
Jerson Reply
life is when any living thing breath or respirate.
Lucky
I want to join
Patrick
me too
Favour
me two
Monday
me too
Bengazy
me too
Maggie
I here
Yahaya
Does anybody knows another biology app that brings good understand
Lucky
give an example of a phylum where all members have open circulatory
Omoro Reply
anthropoda
Daniel
phylum Anthropoda
Daniel
how do u change the unit of temperature from degree celsius to degree Fahrenheit
Maggie
what are beneficial effects in industrial
Nnamani Reply
create employment
ibrahim
provide food
ibrahim
pollution
ibrahim
dirty the environment
ibrahim
pollution and lack of knowledge about how to manage waste
Alex
what is gametophyte
Ibrahim Reply
what is biology
Basiru Reply
Biology deals with the study of living organisms and their interactions with each other and the environment.
Quartey
biology simply means the study of living and non-livingthings.
Shamstar
what is the meaning of ubiquitous
Hamziyatu Reply
Under what topic is this question
fred
three branches of biology
Alexander Reply
what is the cell
Olajide Reply
what is life
Olajide
cell is the functional and structural unit of life
Shweta
life is a problem solving entity
Atanga
what is the characteristics of plant cell
Quaku

Get the best Biology course in your pocket!





Source:  OpenStax, Biology. OpenStax CNX. Feb 29, 2016 Download for free at http://cnx.org/content/col11448/1.10
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Biology' conversation and receive update notifications?

Ask