Tag Archives: Fungi

Plant Galls in a Cloud Forest in Ecuador

gall

On a recent trip to an Ecuadorian cloud forest I was fascinated by the large numbers of diseases and deformities that riddle the plants. Many of these take the form of plants galls.

Galls are abnormal tissue growth on the surface of plants caused by parasites, such as fungi, nematodes, insects, mites or bacteria, the galls are tailored as the perfect place for the parasitic organism to live in. In the past I’ve looked for and found plant galls in England, but it seemed that they were more numerous and varied in Ecuador. I believe there are three reasons for this, all related to Latitudinal Diversity, which is the phenomenon whereby  animal and plant species diversity increases the closer you get to the equator, it applies most notably to rainforests.

  1. With a wider variety of plant hosts, there will be a wider variety of parasites to take advantage of them
  2. A greater number and wider variety of insects leads to more varied insect galls
  3. It is not known for sure that there are more species of fungi and bacteria close to the equator, but it is likely since fungi and bacteria both benefit from a stable environment where light, temperature and humidity are fairly constant, all of which is more true at the tropics than further North or South

What makes galls particularly bizarre, is that these growths are not attachments to the plant, but the plant itself, made to alter its normal growing behaviour in order to benefit its parasite host. Although it is not clear how insects cause this change, bacteria is known to insert its own DNA into the plant cells to alter behaviour. (example here) Insect larvae have been found actually inside the cells of the plant, which might suggest similar interference. It is thought that one wasp (Cynipinae) works in conjunction with a virus (viruses reproduce by inserting their own DNA into the DNA of a host) that lives in the wasps saliva and gets into the plant as the wasp eats it. This is an example of mutualism, since the insect benefits from the virus by getting to make the gall and the virus benefits by getting to reproduce.

Insect and mite galls

These galls are formed by the insect or mite either feeding or laying eggs. When adults lay their larvae on a leaf, excreta or saliva from the insect affects the cambium and causes it to grow differently (more detail above). The larva then grows inside the gall, feeding on the gall itself, eventually eating its way out and escaping. Sometimes the insect control over the plant tissue extends beyond the gall and starches and sugars are drawn in from elsewhere in the plant to increase the food store for the insect.

Insect and mite galls in Ecuador

Insect gall on tree trunk

Insect gall on tree trunk

Underside and Upperside of Leaf

Underside and Upperside of Leaf

Insect galls

Insect galls

Insect galls on Columnea

Insect galls on Columnea

Insect galls showing holes of escaped insects

Insect galls showing holes of escaped insects

Insect galls

Non Gall Insect Invasions

Sometimes I found insects that had taken over leaves, or even entire plants to make a home in. These were not galls, because while leaves were often distorted, the cells were not expanded or changed, but they were still quite bizarre to see.

Ants Forming a Home in a Plant

Ants Forming a Home in a Plant

Wasp Swarm onto Leaf

Wasp Swarm onto Leaf

Insect Colonise a Leaf

Insect Colonise a Leaf

Note: for other insect photos I took in Ecuador, see here

Other Galls

Although some galls I was clearly able to determine as being caused by insects or mites because I could find the animal or see its exit point, others I am just not sure about. The following are those less easy to decipher galls that may be caused by fungi or bacteria.

Leaf Spot Galls

Leaf Spot Gall

Leaf Spot Gall on Decayed Leaf

Leaf Spot Gall on Decayed Leaf

Leaf Distortion due to Gall

Leaf Distortion

The plant in the next photo is a puzzle, the fluffy looking outgrowths at the base of the leaves (and in between) may be a normal part of the plant, perhaps even be the flowers, but they also look similar to the growths in the above picture, which are definitely galls.

Plant Galls or Plant?

Plant Galls or Plant?

This final gall, I believe, is caused by insects because I think it is possible to see them, the black mass at the heart of the distortion.

Severe Leaf Distortion

Severe Leaf Distortion

Close up of Leaf Distortion

Close up of Leaf Distortion

Some interesting and useful websites on plant galls:

Some books I used for reference:

  • British Plant Galls – M. Redfern and P. Shirley
  • The Kingdom Fungi – S. L. Stephenson
  • Parasite Rex – C. Zimmer
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Timeline of Earth and Plant Evolution

Timeline of Earth

Earth's Timeline

Earth’s Timeline

Note: No date from prehistoric Earth can be completely definite. I have done my best to choose reliable dates, but there is much contention with conflicting evidence. Hopefully these diagrams will give a sense of the changes and events occurring within our planet’s history, but I cannot guarantee complete and long lasting accuracy.

The above image is a timeline of Earth’s history, from its formation 4,540 million years ago (mya) to now. The first Eon, Hadean, was a tumultuous one, the planet was still very hot and volcanic and the air was mostly made of carbon dioxide. Although oceans formed about 4,300 MYA ago, they were vapourised by a meteor bombardment that lasted until the Archean Eon.

The Archean Eon saw the first microscopic life, with Bacteria and Archaea evolving, plus the process of photosynthesis started to occur. The Oxygen Catastrophe, a massive increase in oxygen that killed most of the planet’s anaerobic bacteria, occurred in the Proterozoic Eon and was caused by photosynthesizing Cyanobacteria. This also led to the longest period of glaciation (shown by the white edges of the timeline). Acritarch and Grypania are fossils from this time and are thought to be evidence of the first Eukaryotic cells (it is not definite whether either or both are Eukaryots, so I have included both). The multicellular Bangiomorpha is the the first organism to reproduce sexually, and this was a very important development. Without sexual reproduction there could be no mixing of DNA from two parents, which meant that natural selection and consequently evolution, were extremely slow. After Bangiomorpha the change from multicelled, but very simple organisms, to the wide and complex variety of living things we have today, is comparatively fast.

800mya the first multicelled organisms evolved, algae – Cladophora, and around this time another glaciation occurred. The first fungi arrived 700mya, the first animals 665mya. All these organisms lived only in the sea.

The Cambrian Explosion, 530mya, was when many animals appeared, they were arthropods and many of these were crustaceans (see previous blog for more information), here is a great animation of some of those animals. The first big extinction event happened about 50 million years later, in the Phanerozoic Eon (shown on the diagram with a vertical line of crosses), and led to the loss of many animals, especially Trilobites, one of the first Arthropods to have existed. It is interesting to note that while there have been a number of animal extinctions (six can be seen on the diagram) there have been no known plant extinctions and I could find no record of fungi extinctions. This is probably because both plants and fungi are able to survive extreme trauma, regenerating from small portions of root or mycelium. Animals, however, tend die quite easily, the more sophisticated the animal, the more vulnerable it tends to be. Hit an animal on the head or set fire to it and it will probably be dead, but do the same to a plant or fungus and, given a bit of time, they will flourish again.

The Phanerozoic Eon, 542-0mya (we are still in this Eon today) also saw the move onto land by animals, algae and fungi. Whereas animals and fungi had evolved into sophisticated enough forms to be classified in the Fungi and Animal Kingdoms, plants hadn’t appeared at that stage, there was only algae from the Protista Kingdom (see previous blog). Once on land, plants evolved quickly in order to prevent dessication and make use of the greater access to sunlight; seashores played an important part in this transition due to the shifting back and forth from dry to wet. 200mya was the Age of Reptiles, a time of dinosaurs, and their extinction was followed by the Age of Mammals.

Plant Evolution

Plant Evolution

Plant Evolution

Note:

  • All pictures of plants are symbolic representations only, for example the first orchids were unlikely to have looked like the Phalaenopsis that I have drawn.
  • A slightly more accurate, but less clear version of this diagram, with smaller pictures of the plants can be seen by clicking on this thumbnail. The picture of the plant, rather than the writing, marks the time when it is believed to have first appeared.
Plant Evolution

Plant Evolution

Plant evolution happened, like most evolution, in spurts. The first spurt happened during the Silurian and Devonian Period (Periods are subdivisions of Eons, or to be more accurate, Eons are subdivided into Eras which are further subdivided into Periods which are further divided into Ages or Stages, but not until the Phanerozoic Eon. See thumbnail at end of blog.) and involved two important changes, first, soils were created and second, proto-plants developed a cuticle, a waxy covering that stopped them drying out. These two alterations led to the first plants able to grow on land around 475mya, these were probably small non-vascular plants such as mosses or liverworts, sometimes described as bryophytes. Bryophytes do not have properly formed leaves, roots or stems and were, and are, still very reliant on water, this is why they can only be found growing in moist, often shady areas.

Shortly afterwards, vascular plants evolved, Cooksonia, a plant that no longer exists, was one of these and first appeared around 428mya. Plants in the Division Lycopodiophyta were the first vascular plants that still live now. The vascular system is made up of two tubes that travel to all parts of the plant, these are called the phloem and xylem. The xylem carries water from the roots to all parts of the plant and the phloem transports sugars that are made by photosynthesis in the leaves. This system enabled the plants to grow tall and in fact horsetails were part of the first forests (occurring around 350mya) and grew to 30m tall, nowadays they rarely grow more than 150cm tall. Ferns, horsetails and bryophytes all reproduce by spores, a method that requires water.

The next leap forward was conifers in the Carboniferous Period (299-352mya), these had a more developed vascular system than the ferns, and could, and can, grow in drier areas. They also evolved pollen and seeds, rather than spores. Seeds were useful because they were tougher than spores, able to survive for long periods, and relied less on water. Gnetophytes and Ginkgos evolved in the Permian period (252-298mya). These three divisions (Cycadophyta, Gnetophyta and Ginkgophyta) do not contain many species still in existence. Cycadophyta has only three living families, one of which is Cycadaceae which contains palm-like plants (although palm trees are actually flowering plants and only evolved 90mya). Gnetophyta has only three genera and they are odd looking plants, such as Welwitschia mirabilis. Finally Ginkgo which now has only one species, Ginkgo biloba.

Flowering plants the Angiosperms, did not evolve until the Cretaceous Period about 140mya. In the following 100 million years there was another spurt, monocotyledons evolved and orchids (80mya), lilies (60mya) and grasses (50mya) followed, all of which are monocots. Cacti also evolved around this time, about 30mya.

Note: I haven’t shown humans on either timeline, this is because we are such a recent addition that there is not enough detail on the diagrams to be able to mark our appearance. Both timelines mark out every 50 million years, but the genus Homo only evolved 2 million years ago, and the species Homo sapiens 200,000 thousand years ago. Agriculture probably first occurred 12,000 years ago.

Eons, Eras and Periods

Eons, Eras and Periods

Note: On researching further I realised I had made a few errors in this blog, hopefully they are all now corrected.

Kingdom

The Four Kingdom System

There are four kingdoms found in the Eukaryota Domain, they are Fungi, Plantae, Animalia and Protista. Plants and animals are familiar to most people, although there are specific criteria for each that may not be so familiar and a few very odd exceptions. Fungi were once included with plants, but are now known to be very different, and in some ways more similar to animals. Protista is a bit of a hodge podge as kingdoms go, it is unlikely to last much longer as one kingdom, and indeed many scientists have already rejected it because it doesn’t make much sense in evolutionary terms, however, the reordering is still in flux, so I will include Protista as one kingdom.

A clear to understand website about the Protista Kingdom and one from which I got the photo of Giardia lamblia below. http://www.uic.edu/classes/bios/bios104/mike/bacteria01.htm

A website that talks about a possible Seven Kingdom system http://www.fossilmuseum.net/Tree_of_Life/Domain_Eukaryota.htm

Animal

Drosophila

Drosophila

What makes an animal, an animal? Animals are heterotrophs, they cannot make their own food. They can move, are multicellular and reproduce sexually.

Evolutionary history: The earliest animal fossils that have been found are from sponges, dated 665mya, however, animals may have originated 1000mya. Most animals appeared around 542mya and relations of millipedes are the first animals proved to have made it on land 428mya.

Common examples: Crabs, coral, flies, birds and humans.010 (2)

Number of phyla and species: 35 phyla, this includes 13 phyla for different worm-like creatures. The most familiar phyla are:

  • Chordata  – contains mammals, but also fish and reptiles, about 60,000 species
  • Arthropoda  – thought to contain 80% of all living animal species, includes insects, spiders and crustaceans. About a million species have been named, but there are many times that number not yet discovered or classified.

In total it is believed there are between 3 and 30 million species of animal.

LizardHabitats: Polar to desert, temperate to tropical, oceans to mountains.

 

Animal Cell

Animal Cell

Cellular and structural description: Animal cells do not have cell walls or chloroplasts and are often a round shape. Animals contain tissues and organs of a complex nature, for example the tympanal organ for hearing in insects and brain tissue in humans.

Abilities and behaviour: Most animals move at some point in their life-cycle, they breathe out carbon dioxide and breathe in oxygen. They eat food for energy – fungi, plants, bacteria, other animals. Most reproduce using sperm and an egg, although some animals are hermaphrodite or reproduce asexually.

Some exceptional animals: Coral are colonies of genetically identical animals that don’t move. Sponges also don’t move and lack true tissues or organs. Green sea slugs use chloroplasts from algae they eat to then photosynthesize like plants. One species of hornet, Vespa orientalis, may derive energy from the sun. (For some other unusual animals see the Odds and Ends of Nature tab)

Plant

Snowberry

What makes a plant, a plant? Plants are autotrophs, producers, they make food (carbohydrate), by photosynthesis. Plants can’t usually move and their reaction to their environment is slow. They are multicellular and have complex organs and tissues.

Evolutionary history: Although plants originated in the sea, unlike animals and fungi, they did not evolve much there. Green algae (a primitive prototype plant and member of the Protist Kingdom) lived in the sea, but in order to make the move to land, where they could access more sunlight for photosynthesis, they needed to adapt to different, drier conditions. The first plant to grow on land was the now extinct Cooksonia (433-393mya), it had a waxy cuticle to stop the leaves drying out and roots to anchor it to the ground and absorb water. From Cooksonia evolved mosses, liverworts and hornworts (475mya), plants with a very basic ability to transport water. Ferns, followed by conifers and finally all flowering plants, evolved later.

SunflowerCommon examples: Sycamore tree, fern, sunflower, moss and box hedge.

Number of phyla and species: 10 divisions, 270,000 species.

  • Anthocerotophyta – hornworts
  • Marchantiophyta – liverworts
  • Bryophyta – mosses
  • Lycopodiophyta – club and spike-mosses
  • Pteridophyta – ferns and horsetails
  • Gnetophyta – 3 extant genera of woody plants
  • Cycadophyta – cycads
  • Ginkgophyta – Ginkgo
  • Pinophyta/Coniferophyta – conifers
  • Magnoliophyta – flowering plants

More on Divisions and plant evolutionary history in future blogs.

Habitats: Diverse, just about anywhere with air and sunlight.

 

Plant Cell

Plant Cell

Cellular and structural description: Plants cells have cell walls made of cellulose and chloroplasts. They have a very rudimentary circulatory system and the ability to sense their environment, but only simply – they can detect sunlight, but not see images, they can react to touch but it is mostly a slow process. They have organs and tissues, for example, the leaf is an organ and on its surface is photosynthetic tissue.

Abilities and behaviour: Plants are generally rooted in one place and do not move on their own, however they can grow in response to their environment. They give off oxygen and take in carbon dioxide through photosynthesis, a process which uses sunlight to make carbohydrate, which is then broken down by the plant for energy, however it is often consumed by fungi or animals instead. Plants reproduce sexually by fusing egg and sperm, but being unable to move they need different methods to transport the sperm to where the egg is, for example using wind or insects.

Some exceptional plants: Mimosa pudica can move, responding instantly to touch by collapsing its leaves against the stem, this is a defensive measure that hides the leaves from animals that might eat them. Ivy broom rape does not photosynthesize, but parasitizes ivy, growing from its roots in a similar manner to fungi. Some plants trap insects and digest them for nutrients, but not for energy in the way that animals do, these plants often move also, for example Venus Fly Trap. The Socratea exorrhiza is a tree described as being able to walk, but this is not walking in the way an animal would; it involves having above ground roots that move towards the sunlight by growing more roots on one side and allowing those on the shady side of the plant to die, so that in time the plant shifts both over- and underground.

Fungi

Fungus

Fungus

What makes fungi, fungi? Fungi are heterotrophs, decomposers that cannot make food so they grow on living or dead organisms, breaking them down.

Evolutionary history: The first fungi were in the sea probably dating from 760-1060mya, fungi colonised the land long before animals or plants, probably 542-488mya.

Common examples: Athlete’s foot, coral spot (bright orange dots sometimes seen on leaves), white mushrooms, truffles, penicillin, bread mould.

 

 

Number of phyla and species: 6 phyla (although a seventh has been proposed). They are:

  • Chytridiomycota
  • Zygomycota
  • Ascomycota
  • Basidiomycota
  • Glomeromycota
  • Blastocladiomycota

10,000 species of fungus have been described, but there are thought to be at least a million. Fungi are more varied in the tropics than in areas closer to the North or South pole. For example in Britain and Ireland fungi outnumber plants 6:1, in Southeast Asia the ratio is 33:1.

Habitats: Fungi need plants, animals or other fungi to grow on or with. Most live on land, but a few live in water. Plenty live inside other organisms.

 

Fungal Cell

Fungal Cell

Cellular and structural description: Fungi have cell walls like plants, but made of chitin, the substance found in the hard exoskeletons of insects, rather than cellulose. The main part of a fungus is the mycelium, small threads that attach to other organisms to obtain food, these mycelium can grow for several km. Most fungi produce fruiting bodies these are what we think of as mushrooms, but are only a fraction of the actual fungus. Fungi have a simpler structure than plants or animals, but the fruiting body is an organ and it is made of tissue.

Abilities and behaviour: Fungi cannot photosynthesize and must consume food, they do this by attaching to other organisms (plants, animals or other fungi) by filaments and then take food from their host – sometimes this is a parasitic relationship, sometimes symbiotic (mutually beneficial, eg the fungi provides a means of extracting nutrients from the soil for its host plant) and sometimes saprophytic (consuming dead material, this is an essential part of the process whereby dead organisms break down, without these fungi the planet would be filled with dead bodies.)

Xanthoria Lichen

Xanthoria Lichen

Some exceptional fungi: Lichens are composite organisms, made up of fungi and algae working together. The alga can photosynthesize and so provides food for the fungus and the fungus protects the alga from desiccation in harsh environments. Lichens can grow in environments that neither algae or fungi could survive in alone. Along with bryophytes, lichens were probably some of the first organisms on land. Some lichens also contain Cyanobacteria (a bacteria).

Protist

Giardia lamblia

Giardia lamblia

What makes a protist, a protist? Essentially any organism that cannot be classified as a fungi, plant, animal, bacteria or archaea is classified as a protist, most protists are prototype fungi, plants and animals.

Evolutionary history: Algae were probably the first protists to appear, 1600-1700mya.

Common examples: Kelp, amoebas (Protozoa), seaweed, algae, the cause of malaria and sleeping sickness (NB: cyanobacteria are sometimes referred to as blue-green algae, but they are in the

Protozoa

Protozoa

Bacteria Domain), slime molds, diatoms (type of  algae). Volvox is a genus of single celled protists that live in colonies (see Odds and Ends of Nature tab for more about these and slime molds).

Number of phyla and species: 200,000 species. Usually ten phyla, although these often change.

Habitats: Protists live mostly in wet places, the sea, a damp corner, or an animal intestine.

Algae

Algae

Cellular and Structural description: Most are unicellular and invisibleto the naked eye. They are more complex than bacteria and have their nuclei wrapped in a membrane, but simpler than other eukaryotes having no specialised tissues, they do, however, have organelles in their cells such as mitochondria and chloroplasts.

Abilities and behaviour: Some protists are autotrophs, some are heterotrophs, some photosynthesize and expire oxygen, others consume and breathe in oxygen. The protists that move do so by a number of means such as pseudopodia or flagella.  Most Protists reproduce asexually, a few reproduce sexually and some alternate between the two.

Some exceptional protists: All protists are exceptions really.

Note: I recently received an email from someone helpfully pointing out that cells have only one Golgi apparatus, rather than the several that I had drawn. I have since altered these diagrams, sorry for the misinformation and thank you to the informer.