Why did trees evolve into two main groups--deciduous and conifer?

Question

Animals didn't evolve into two main groups.
Neither did other plants.
Why trees?

Answer 1

You have made a number of errors in your assumptions.

1) Trees are plants, so plants did evolve into two groups: gymnosperms (Conifers) and angiosperms (Flowering plants).

In fact, there are many angiosperm trees which are evergreen such as Southern Magnolia, American Holly, and Wax Myrtle. At the same time there are some gymnosperms which are deciduous such as Cypress Trees, Ginko trees, and Dawn Redwoods.

The more appropriate way to approach this question would be ask why did plants evolve into angiosperms and gymnosperms (of which a characteristic is gymnosperms being mostly evergreen). There is no 'simple' answer to this question, but I will give it a try.

Vascular plants started in moist habitats with mosses and then moved to ferns and fern allies. These plants utilized water to transport spores for fertilization and sexual reproduction. As plants became more advanced and developed improved vascular tissue they could grow larger and move away from moist habitats.

This required a new more of reproduction and the conifers were born. They used wind to transport spores longer distances to other trees for reproduction. These are your present day Gymnosperms (conifers).

The evolution of leaves and insects gave rise to flowers. It became more efficient to produce a small amount of pollen which insects could transport to another plant. This gave rise to our angiosperms.

2) Animals didn't evolve into two main groups.

It depends on what you want to consider a group. But I think animals have evolved into many groups: Birds, mammals, fish, reptiles (which are all members of the cordata phylum).

You also have Insects, worms, sponges, etc etc. I am not a Zoologist so I can't speak intelligently on how animals are classified. But I do know there are lots of evolutionary groups within the animal kingdom.

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If your wondering though why some plants are deciduous and some are evergreen. It was more than likely a response to the new environments plants were exposed to as the colonized larger areas of the planet.

In the tropical region where plants are thought to originate there was plenty of sun, nutrients, and water which would allow a plant to grow and produce leaves year round.

However, as plants evolved and colonized more temperate regions the environment wouldn't support plant growth during cold, darker winters. In response, more advanced plants lost there leaves during the winter because they used more energy than they created by maintaining leaves.

In some areas like the coasts though it stays warm enough with enough moisture and nutrients and plants can retain there leaves even during winter months.

Long story short here...... deciduous trees (angiosperm or gymnosperm) are probably a result of evolutionary response to a new climate.

Answer 2

Actually, there are more than two main groups. Before regular conifers, there lycopods; then plants with seeds competed better on land, and gymnosperms developed. First,, there were forests of cycads. Later, the conifers dominated. Later the angiosperms (including most deciduous trees) developed. Because they were radiating at the same time as insects, there was an explosion in the number of different types. See the web site below for a more thorough explanation of the evolution of trees.

Answer 3

Animals evolved into two groups: vertebrates and invertebrates. Vertebrates evolved into two groups: those that lay land eggs and those that don't. Mammals evolved into two groups: egg-layers and non-egg layers. Non-egg layers evolved into two groups: marsupials and placentals. Monkeys evolved into two groups: new world monkeys and old-world monkeys.
Other plants evolved into two groups: vascular plants and non-vascular plants. Vascular plants evolved into two groups: seed plants and those that don't have seeds. Seed plants evolved into two groups: naked seeds and covered seeds. Flowers evolved into two groups: monocots and dicots.

Most anything can be divided into two groups, so your question has more to do with why people like to divide things into two groups. (Even when there is a range of intermediates.)
Another way to look at it is, any time a new feature evolves, there will be those with it and those without it, so there are always two groups. So trees either lose their leaves or not, so (surprise) you have two groups. But not all trees would fit neatly into your two groups--what about larch and bald cypress, which are deciduous conifers?
But deciduous and conifer are not what we call "natural" groups (grouped by evolutionary relationships).
Some divisions into two groups have more significance than others, and we can easily classify things into any number of groups. One could argue that trees evolved into three main groups: Ginkgo, gymnosperms and angiosperms.
So the short answer is, trees didn't evolve differently than anything else.

Answer 4

not sure why it happened but sure glad it has turned out this way because can you imagine how dismal winter would be with ALL the trees bare at the same time..birds and animals would suffer too

Answer 5

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