It’s British Science Week from 11th-20th March 2016 and so for this blog, I shall mostly be putting on my white coat and talking genetics.
What Are Genetics?
Genetics is defined in the Oxford Dictionary as “The study of heredity and the variation of inherited characteristics”. In terms that you and I can understand, it’s all about the way that living things look, taste, reproduce, grow and adapt to their environment.
Where plants are concerned, their genetics affects
- Leaf shape and colour
- The size of the mature plant
- It’s growth habit (plant, shrub or tree)
- How fast it grows
- How long it lives (annual, biannual or perennial)
- How well it copes with frost, heat, drought, waterlogging etc
- Size, shape and colour of flowers
- How it is pollinated (wind, water, insects or birds)
- How seeds are distributed
- Whether it has thorns, a nasty taste, poison etc to protect itself from predators
A typical countryside scene with wildflowers in the foreground, wild hedge plants and trees in the background and a cultivated crop sandwiched between them. The genetic diversity in this picture is vast. Some are natural, some has been influenced by man.
Genetics and Biodiversity
Genetics and biodiversity are so closely linked that you can talk about one without the other.
It is estimated that there are 400,000 plant species in the world, almost 3,000 of which grow in the UK. Within those species are cultivars – for example, the rose is a species with thousands of different cultivars, there are at least 40 cultivars of wheat in the UK and 7,500 types of apple.
Each plant has different characteristics according to its genetic makeup. And those characteristics are linked to other lifeforms – insects, birds, mammals that use plants as a source of food and somewhere to live.
This goldfinch has evolved over centuries to make the most of the seeds provided by the burdock plant. The burdock, in its turn, has evolved to attract birds and animals to help distribute its seeds.
How Did So Many Plants Evolve To Be So Different From Each Other?
- Natural selection – only the plants most suited to their environment survive to pass their characteristics on to their offspring
- Human intervention
Humans are responsible for breeding plants to suit their purposes. A tastier type of tomato, a flower with stripy petals, strawberries that ripen later in the summer, potatoes that make good chips, other potatoes that are nice in salads. We’re forever fiddling with plant genetics.
If New Plant Varieties Perform Better, Why Do We Need To Preserve The Originals?
All of the plants that grow naturally without drastic human intervention (so not including grafted plants like the tomato) have descended from wildflowers and trees. The “modern” plants share some features with their ancestors but also have some new characteristics and have lost some of the old ones. For example, modern wheat varieties have developed from spelt. Spelt doesn’t yield nearly as highly as wheat, but it doesn’t contain gluten either. So there are pros and cons to every change.
The tomato has a tomato plant grafted to a potato plant and grows both fruit and veg on the same plant. Is this genetic diversity? No. This plant cannot reproduce naturally, it needs a lot of human intervention.
If scientists decided that they wanted to breed a variety of wheat that yields well but doesn’t contain gluten, they would need to go back to the beginning and start selectively breeding spelt.
Do you see where I’m coming from?
Now, many of our wildflowers have properties beyond being pretty. The meadows, hedgerows and woods of ancient times were medicine chests and a myriad of different concoctions were made using oils, roots, leaves and flowers.
Those plants still have healing powers, that their descendants may very well have lost. Take the foxglove, Digitalis purpurea It’s a native English Wildflower used widely to treat heart disease. It’s healing properties were discovered in the 18th century when the physicist William Withering happened upon a secret recipe used by an “old woman in Shropshire” to treat dropsy……….there must be other opportunities out there, but if we lose the wildflower gene-stock we’ll lose the chance to find them.
Field scabious. A UK wildflower once used to treat scabies. Could it be healing properties be harnessed by scientists in the future?
How’s This For An Example?
There’s a native wildflower in North America called Tradescantia Virginiana or Spiderwort. In the “olden days,” it was thought to cure spider bites. It’s commonly used in laboratories for the study of cell structure (which includes genes and chromosomes).
Some super-observant plant scientists spotted that the plant is sensitive to pollution and to radiation. When it’s exposed to harmful substances, the flowers which are normally blue, very quickly turn red. Consequently, this wildflower is now deliberately planted on sites that are at risk of pollution. It provides an inexpensive but accurate way of testing for contamination.
A prime example of how we’re still finding out about the power of wildflowers…………
A Scientist’s Explanation
Dr Pamela Collins sums the situation up beautifully. She’s talking about Tobago, but it could be anywhere in the world.
“The status of our biodiversity in Tobago, as elsewhere, has always been dynamic. Over millions of years, under natural conditions, some species have increased in variety or numbers and others have been reduced or lost. Some people wonder why we should be worried about conserving biodiversity now, in particular, when the world has gone on more or less as it is for so long. But natural habitats everywhere are being assaulted as never before and as habitats are lost we are also losing various types of plants and animals. No one would have thought, even a few years ago, that the common house sparrow of Britain could be endangered, but now it is. With the rapid changes we are seeing in Tobago, there are concerns that man-made changes to our environment are leading to too many of our species being lost and our biodiversity becoming seriously depleted.
One of the reasons biodiversity is important is because it helps to keep the environment in natural balance. An ecosystem which is species-rich is more resilient and adaptable to external stress than one in which the range of species is limited. In a system where species are limited, the loss or temporary reduction of any one could disrupt a complex food chain with serious effects on other species in that same system. Once biodiversity is sufficient, if one nutrient cycling path is affected another pathway can function and the ecosystem – and the biological species it supports – can survive.”
How Can You Preserve The Wildflower Gene Pool?
You can plant a wildflower patch in your own garden.
If you’re short of space, you could ask your community or local authority to manage road verges and public areas differently.
Support wildflower centres and nature reserves because they’re fantastic at encouraging biodiversity.