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What are conifers? Pine trees, gymnosperms

By |2018-04-21T11:56:36+00:00May 30th, 2017|Biology|

Spruce tree - a type of gymnosperm and conifer Near the end of the Carboniferous period, about 300 million years ago, the land on Earth got a lot drier than it had been before. It was drier because plate tectonics was bringing all of the land together into one big continent, Pangaea. Plants that [...]

Collecting pine cones – Gymnosperms project

By |2018-04-16T10:35:31+00:00May 30th, 2017|Biology|

Squirrel eats pine seeds from a cone Go take a walk outside in the fall and collect pine cones on the ground. How many different kinds of pine cones can you find? Can you figure out which tree makes which kind of pine cone? Sit quietly near a pine tree and watch squirrels [...]

Looking at flowers – Angiosperms project – Biology

By |2018-04-16T10:36:08+00:00May 30th, 2017|Biology|

Daffodil with petals and pistil in the middle. Take a long walk around your neighborhood and the park in the late spring and look at all the flowers you see. Can you find ten different kinds of flowers? What does each of these flowers do to attract bees? Is it their color? Their [...]

What is a spore? – Plant reproduction – Biology

By |2018-04-13T23:51:51+00:00May 30th, 2017|Biology|

Fern spores on the underside of a frond When plants like moss first began to grow outside the water, about 540 million years ago, they needed a way to reproduce themselves that didn't depend on water so much. Some of these plants evolved to be able to produce spores. To make spores, plants [...]

Seeds – Plant reproduction – Biology

By |2018-04-13T17:51:52+00:00May 30th, 2017|Biology|

Evolution of seeds: Dandelion seeds What is a seed? A seed is the egg cell of a plant, with a hard wrapper around it so it can survive on its own. The earliest plants with seeds evolved from plants with spores during the late Devonian period, about 360 million years ago. The seeds [...]

Plant reproduction – Biology – Science

By |2018-04-13T17:52:39+00:00May 30th, 2017|Biology|

Cell division The very earliest photosynthesizing plants on Earth, about 3 billion years ago, had only one cell, and they reproduced the way most one-celled creatures do, by mitosis: splitting themselves in half. By about two billion years ago, some of these cells began to split themselves in a more sophisticated way, called [...]

Haploid and diploid cells – Plant reproduction

By |2018-04-13T17:05:53+00:00May 30th, 2017|Biology|

Human sperm cells with flagella (under a microscope) - They're haploid cells. When a cell divides by meiosis, it ends up with only half the amount of DNA it had before. That is a haploid cell. When two haploid cells join together to make one new cell with the regular amount of DNA, that's [...]

How flowers reproduce – Plant Biology

By |2018-04-13T17:05:54+00:00May 30th, 2017|Biology|

Black-eyed Susan (the black in the middle is the seeds) The earliest flowers probably developed about 130 million years ago, in the Cretaceous period, as a way to attract newly evolved flying insects - mainly bees - and get them to help spread the plant's pollen far away from where the plant was [...]

Eggs – Evolution and Biology

By |2018-04-16T10:33:22+00:00May 29th, 2017|Biology|

Fish eggs The earliest living creatures made babies by dividing themselves in half, so that one cell became two cells. But about 1.4 billion years ago, some creatures with more than one cell began to develop specialized cells that could combine with the cells from another creature to make a new creature. These were [...]