What Are Angiosperms?

Questions and Answers

What is the approximate percentage of known plant species that are angiosperms?

60%

70%

90%

80% (correct)

What is the main reason for the evolutionary success of angiosperms?

Their root system

The structure of their leaves

The co-evolution of animals (correct)

Their ability to grow in extreme environments

What is the term for the group of plants that produce fruit once the seeds are fertilized in the flower structure?

Gymnosperm

Cycadeoidales

Pteridospermales

Angiosperm (correct)

Approximately how many years ago did angiosperms thought to have evolved?

247.2 million years ago Signup and view all the answers

What is thought to be one of the ancient and extinct plant groups that angiosperms may have evolved from?

Pteridospermales Signup and view all the answers

What is the term for flowers that contain both male and female parts?

Bisexual or perfect flowers Signup and view all the answers

What is the function of the anther in a flower?

To produce the pollen, which is the male haploid cell Signup and view all the answers

What is the term for the life cycle stage where cells have two sets of chromosomes?

Diploid stage Signup and view all the answers

During which stage of the angiosperm life cycle are gametes produced?

Haploid stage Signup and view all the answers

What is the term for the collective female parts of a flower?

Pistil Signup and view all the answers

What is the function of the filament in a plant?

To provide support to the anther Signup and view all the answers

What is the term for the process by which one sperm cell fuses with the egg cell and another sperm cell fuses with a cell of the female gametophyte?

Double fertilization Signup and view all the answers

What is the term for the cell that contains three sets of chromosomes?

3n cell Signup and view all the answers

What is the purpose of the endosperm?

To act as a food and nutrient supply for the embryo Signup and view all the answers

What is the term for the life stage that begins after fertilization?

Diploid stage Signup and view all the answers

Study Notes

What is an Angiosperm?

Angiosperms are flowering vascular plants, making up approximately 80% of all known plant species on Earth.
The term "angiosperm" comes from the Greek words "angio" meaning vessel and "sperm" meaning seed, referring to the fruit that holds fertilized seeds.
Angiosperms are incredibly diverse, with over 300,000 living species categorized into eight genetic groups.

Angiosperm Evolution

Angiosperms are thought to have evolved near the equator around 247.2 million years ago during the Triassic period.
Fossilized pollen from this era has been found, and angiosperms continued to evolve and diversify throughout the Cretaceous period (100-66 million years ago).
Angiosperms likely evolved from ancient and extinct plant groups, such as Pteridospermales and Cycadeoidales.

Angiosperm Structure

Angiosperms have distinct parts and characteristics, including the flower structure, which is specialized for specific functions.
Flowers can be classified into three groups: bisexual or perfect flowers (containing both male and female parts), unisexual or imperfect flowers (with separate male and female flowers), and monoecious or dioecious flowers (with flowers on the same or different plants).
The flower structure includes the sepal, petals, stamen, and pistil, with the male parts producing pollen and the female parts containing ovules.

Angiosperm Reproduction

Angiosperms have a life cycle that involves the alternation of generations, with haploid and diploid stages.
The haploid stage involves the production of gametes (sperm and egg cells) with one set of chromosomes, while the diploid stage involves the formation of zygotes with two sets of chromosomes.
During fertilization, a pollen grain enters the ovary, and the sperm cell combines with the egg cell, creating a zygote.

Haploid Stage

The haploid stage involves the production of gametophytes, including the male gametophyte (pollen) and female gametophyte (ovule).
The male gametophyte contains two sperm cells, while the female gametophyte contains the egg cell.
During the haploid stage, the gametophytes are produced within the male and female parts of the flower.

Diploid Stage

The diploid stage begins after fertilization, when the zygote forms and has two sets of chromosomes.
The diploid stage involves the formation of the endosperm, which provides nutrients for the developing sporophyte (seedling).
The sporophyte matures and produces flowers, which in turn produce gametophytes, starting the cycle anew.