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I found a dozen of these small trees in a local park that is just an overgrown homestead. The leaves look something like an elder but the flower clusters surrounded by white, four petaled false flowers are completely unknown to me. What species is this?
Location: Shenandoah valley in central Virginia, U.S.A.
- Sandy soil on inside of a sharp curve of the South River, just above the flood plain. This area has been occupied by people, for a couple hundred years, so this could very well be a cultivated plant.
This is very likely some species of Viburnum.
Viburnum is a genus of about 150-175 species of shrubs in the Adoxaceae family that are primarilly native throughout the temperate Northern Hemisphere.
All species of viburnum (as far as I know) have opposite leaves, as does the specimen in the picture.
Many species of Viburnums bloom in white in the last part of April through early May, and typically you have to pay attention to flower shape and often, more importantly, the leaf shape to differentiate species.
Without location information, an exact species ID is not guaranteed, but your specimen looks very similar to:
Doublefile Viburnum (Viburnum plicatum)
Source: Dave's Garden
Source: Missouri Botanical Garden
This species produces two rows of white flower clusters, with both small and large flowers, along the stem.
According to Wikipedia: Viburnum plicatum is a popular ornamental plant, both in its native area and in various temperate regions.
Based on the "double" flower types of your specimen, it's likely V. plicatum f. tomentosum:
Cultivars with wild-type flowerhead structure are sometimes described as a separate botanical form V. plicatum f. tomentosum. They include 'Cascade', 'Lanarth' and 'Rowallane'.2 Two cultivars in this group, 'Mariesii' and 'Pink Beauty', have gained the Royal Horticultural Society's Award of Garden Merit.
Habit: A deciduous, multi-stemmed medium-sized shrub that typically reaches 2.5 3 m tall. [Source].
Leaf: ovate, 5-10 cm long, up to 5 cm wide; pointed apex and rounded leaf base; serrated leaf margin; 8 to 12 pairs of veins; pubescent underside; dark green leaf color. [Source].
Flowers: individual flowers form a large (up to 10 cm diameter) flat-topped cyme composed of showy infertile flowers surrounding unshowy fertile flowers. Blooms in May. [Source].
6.13: Aquatic Organisms
- Contributed by CK-12: Biology Concepts
- Sourced from CK-12 Foundation
What is this? Plant or animal?
It is actually the Yellow Christmas tree worm. These animals are colorful, and can be red, orange, yellow, blue, and white. The Christmas tree worm lives on tropical coral reefs throughout the world. The Christmas tree worm's plumes are used for feeding and respiration. These worms use their plumes to catch plankton and other small particles passing in the water. Cilia then pass the food to the worm's mouth.
What is this small tree? - Biology
A phylogenetic tree can be read like a map of evolutionary history. Many phylogenetic trees have a single lineage at the base representing a common ancestor. Scientists call such trees rooted, which means there is a single ancestral lineage (typically drawn from the bottom or left) to which all organisms represented in the diagram relate. Notice in the rooted phylogenetic tree that the three domains—Bacteria, Archaea, and Eukarya—diverge from a single point and branch off. The small branch that plants and animals (including humans) occupy in this diagram shows how recent and miniscule these groups are compared with other organisms. Unrooted trees don’t show a common ancestor but do show relationships among species.
Figure 1. Both of these phylogenetic trees shows the relationship of the three domains of life—Bacteria, Archaea, and Eukarya—but the (a) rooted tree attempts to identify when various species diverged from a common ancestor while the (b) unrooted tree does not. (credit a: modification of work by Eric Gaba)
In a rooted tree, the branching indicates evolutionary relationships (Figure 2). The point where a split occurs, called a branch point, represents where a single lineage evolved into a distinct new one. A lineage that evolved early from the root and remains unbranched is called basal taxon. When two lineages stem from the same branch point, they are called sister taxa. A branch with more than two lineages is called a polytomy and serves to illustrate where scientists have not definitively determined all of the relationships. It is important to note that although sister taxa and polytomy do share an ancestor, it does not mean that the groups of organisms split or evolved from each other. Organisms in two taxa may have split apart at a specific branch point, but neither taxa gave rise to the other.
Figure 2. The root of a phylogenetic tree indicates that an ancestral lineage gave rise to all organisms on the tree. A branch point indicates where two lineages diverged. A lineage that evolved early and remains unbranched is a basal taxon. When two lineages stem from the same branch point, they are sister taxa. A branch with more than two lineages is a polytomy.
The diagrams above can serve as a pathway to understanding evolutionary history. The pathway can be traced from the origin of life to any individual species by navigating through the evolutionary branches between the two points. Also, by starting with a single species and tracing back towards the “trunk” of the tree, one can discover that species’ ancestors, as well as where lineages share a common ancestry. In addition, the tree can be used to study entire groups of organisms.
Another point to mention on phylogenetic tree structure is that rotation at branch points does not change the information. For example, if a branch point was rotated and the taxon order changed, this would not alter the information because the evolution of each taxon from the branch point was independent of the other.
Many disciplines within the study of biology contribute to understanding how past and present life evolved over time these disciplines together contribute to building, updating, and maintaining the “tree of life.” Information is used to organize and classify organisms based on evolutionary relationships in a scientific field called systematics. Data may be collected from fossils, from studying the structure of body parts or molecules used by an organism, and by DNA analysis. By combining data from many sources, scientists can put together the phylogeny of an organism since phylogenetic trees are hypotheses, they will continue to change as new types of life are discovered and new information is learned.
Similar to trees, the variation in shrub height is attributed to the environments for which they are adapted and grow. One method of categorizing the different types of shrubs is based on the structural traits, height, and foliage coverage.
Small shrubs are typically less than 2 meters in height and can be further categorized based on foliage (see photo below).
- Dense Foliage: Small shrubs with dense foliage have between 70% and 100% foliage coverage and are found in closed low shrublands typically characterized by acidic soil and drier climates.
- Mid-Dense Foliage: These are shrubs with only 30% to 70% foliage coverage, and are found in mid-dense low shrublands, such as Hawaii.
- Sparse Foliage: These shrubs are characterized by only 10% to 30% foliage coverage and found in low shrublands.
- Very Sparse Foliage: Shrubs with less than 10% foliage coverage are found in sandy, dry low open shrublands. These shrubs are typically found in desert climates
Mid- to Large-sized shrubs
Mid to large-sized shrubs are typically between 2 and 8 meters in height and similar to small shrubs, can be categorized based on foliage (shown below).
- Dense Foliage: Large shrubs with dense foliage have between 70% and 100% foliage coverage and are called closed shrubs.
- Mid-Dense Foliage: These are shrubs with only 30% to 70% foliage coverage, and are termed open shrubs.
- Sparse Foliage: These shrubs are characterized by only 10% to 30% foliage coverage and found in tall shrublands, such as those found in Australia.
- Very Sparse Foliage: Shrubs with less than 10% foliage coverage are found in tall open shrublands. These shrubs are typically found in desert climates
1. Shrubs can be distinguished from trees based on:
B. The number of stems
D. A and B
What is this small tree? - Biology
An introduction to evolution
|Leaves on trees change color and fall over several weeks.||Mountain ranges erode over millions of years.|
|A genealogy illustrates change with inheritance over a small number of years.||Over a large number of years, evolution produces tremendous diversity in forms of life.|
Download this series of graphics from the Image library.
Biological evolution, simply put, is descent with modification. This definition encompasses small-scale evolution (changes in gene &mdash or more precisely and technically, allele &mdash frequency in a population from one generation to the next) and large-scale evolution (the descent of different species from a common ancestor over many generations). Evolution helps us to understand the history of life.
Biological evolution is not simply a matter of change over time. Lots of things change over time: trees lose their leaves, mountain ranges rise and erode, but they aren't examples of biological evolution because they don't involve descent through genetic inheritance.
The central idea of biological evolution is that all life on Earth shares a common ancestor, just as you and your cousins share a common grandmother.
Through the process of descent with modification, the common ancestor of life on Earth gave rise to the fantastic diversity that we see documented in the fossil record and around us today. Evolution means that we're all distant cousins: humans and oak trees, hummingbirds and whales.
1. Name 3 things that the cross section of a tree can tell you about the tree?
2. What is a false ring? _________________________________________________
3. The dark rings on the tree are called [earlywood / latewood ] .
4. The cells produced during the summer are [ larger / smaller ] than spring cells.
5. The oldest layer of growth is near the [ center / outside ] .
6. If a tree had to grow around an obstacle, the rings would be [ lopsided / scarred ].
7. Ring scars are caused by [ damage / earlywood ]
Examine the rounds: tree rounds have three distinct regions. The outer region, or bark , is separate from the area of wood on the inside. The center, or core, of the tree is the pith , which is small in comparison to the larger area of wood. Less noticeable region is the thin cambium , which lies between the bark and wood. Wood rays appear as lines radiating from the pith to the outside of the wood like spokes of a wheel. The wood area is further divided into two regions. The outer area of the new growth is usually light in color and represents the live tissue called sapwood . The inner area is darker, and is dead tissue called heartwood . Sometimes this is filled with gums and resins which gives it a very dark color.
Locate all the underlined structures on your tree rounds. Make a sketch of one of them below and label each region (or structure) that is underlined above. Use shading to help distinguish the areas of sapwood and heartwood.
Researchers Discover Ultra-Small Bacteria
An international team of scientists, co-led by Dr Luis Comolli of the Lawrence Berkeley National Laboratory and Prof Jillian Banfield of the University of California, Berkeley, has captured the first detailed images of ultra-small bacteria that are believed to be about as small as life can get.
Colorized cryo-TEM image shows numerous hair-like appendages radiating from the surface of this ultra-small bacteria cell. Scale bar – 100 nm. Image credit: Birgit Luef et al.
“These newly described ultra-small bacteria are an example of a subset of the microbial life on Earth that we know almost nothing about,” said Prof Banfield, who is the senior author of a paper published in the journal Nature Communications.
“They’re enigmatic. These bacteria are detected in many environments and they probably play important roles in microbial communities and ecosystems. But we don’t yet fully understand what these ultra-small bacteria do.”
The existence of ultra-small bacteria has been debated for more than twenty years, but there hasn’t been a comprehensive electron microscopy and DNA-based description of the microbes until now.
The newly-discovered ultra-small bacteria, which belong to WWE3, OP11, and OD1 microbial phyla, have an average volume of 0.009 cubic microns.
They were found in groundwater collected at Rifle, Colorado, and are thought to be quite common.
They are also quite odd, which isn’t a surprise given the cells are close to and in some cases smaller than several estimates for the lower size limit of life.
This is the smallest a cell can be and still accommodate enough material to sustain life.
These bacteria have densely packed spirals that are probably DNA, a very small number of ribosomes, hair-like appendages, and a stripped-down metabolism that likely requires them to rely on other bacteria for many of life’s necessities.
“There isn’t a consensus over how small a free-living organism can be, and what the space optimization strategies may be for a cell at the lower size limit for life,” said first author Dr Birgit Luef from the Norwegian University of Science and Technology in Trondheim, Norway.
“Our research is a significant step in characterizing the size, shape, and internal structure of ultra-small cells.”
Birgit Luef et al. 2015. Diverse uncultivated ultra-small bacterial cells in groundwater. Nature Communications 6, article number: 6372 doi: 10.1038/ncomms7372
The goal of a classifier is to obtain the best predictive accuracy for new unlabeled data. Decision trees classifiers have also to control the size of the final tree, as a small tree would lead to underfitting issues and a complex tree to overfitting issues.
Therefore, it is possible to define a fitness function that balances between these two criteria:
- f1 is the accuracy on the training set
- f2 penalizes the size of an individual in terms of depth of the tree
- α1 and α2 are parameters to be chosen.
Phylogenetic Tree – Canines
This activity was designed for an introductory (semester long) biology class. I don’t often have time to go into taxonomy with much depth, but I do like to include major concepts, like kingdoms and scientific names with the unit on evolution. This worksheet has students look at three canid species: wolf, coyote, and dog, and then determine which is most closely related.
Students first read descriptions of the three species and are asked to underline features that the dog and wolf share, then place a star next to similarities to a coyote. The goal here is to make some general comparisons. Then, students examine a phylogenetic tree which has questions for them to discover how the tree is organized. Students will learn what a node is, and how branches on the tree represent descendants from a common ancestor. In addition, students are introduced to the concept of a scientific name (genus + species) and subspecies, as in the case of a domestic dog.
This activity can be done is small groups or as a whole class guided exercise. A guided activity does allow room for whole class discussion on what makes a dog different from a wolf or a coyotes. If you have watched the film “Dogs Decoded” this is a great follow-up activity to bridge the unit of genetics and evolution. Students will also start with many preconceived notions about what a wolf is, allowing for some rich in-class discussions about domestication and animal behavior.
A tree converts disorder to order with a little help from the Sun
The concept of entropy and the second law of thermodynamics suggests that systems naturally progress from order to disorder. If so, how do biological systems develop and maintain such a high degree of order? Is this a violation of the second law of thermodynamics?
Order can be produced with an expenditure of energy, and the order associated with life on the earth is produced with the aid of energy from the sun. The raw materials for the nutrients for life on the Earth are just carbon dioxide and water! The mechanisms of advanced plant and animal life add nitrogen, phosphorus and sulfur with most of life's operational mechanisms accomplished with the elements summarized in the mnemonic CHONPS.
The building materials are in a highly disordered state - gases, liquids and vapors. The tree takes in carbon dioxide from the air, water from the earth as well as a small amount from water vapor in the air. From this disordered beginning, it produces the highly ordered and highly constrained sugar molecules, like glucose. The radiant energy from the Sun gets transferred to the bond energies of the carbons and the other atoms in the glucose molecule. In addition to making the sugars, the plants also release oxygen which is essential for animal life.
The leaves use the energy from the sun in tiny energy factories called chloroplasts. Using chlorophyll in the process called photosynthesis, they convert the sun's energy into storable form in ordered sugar molecules.
As an example of the scope of this process, consider a mature maple tree. It may have 500 pounds of green leaves employed in the process of photosynthesis. Having a leaf surface area of several hundred square meters, it is capable of making some 2 tons of sugar.
The process of photosynthesis in plants stores energy in the plants which can be used for accomplishing work. Some of the energy is used for the synthesis of carbohydrates. These carbohydrates may be simple sugars like glucose or complex combinations of sugars. Some of the common carbohydrates are:
|Cellulose||Long chains of glucose molecules which are fairly linear. They help maintain the plant structure - the wood of trees is primarily cellulose.|
|Starch||More highly branched chains of glucose molecules. They are produced by plants and serve as energy resources for the plants. They can be metabolized by humans and other animals for energy.|
|Glycogen||Even more highly branched chains of glucose, but similar to starches. Used by plants and animals for energy storage. For animals, this glycogen storage is primarily in the muscles.|
In animal systems there are also small structures within the cells called mitochondria which use the energy stored in sugar molecules from food to form more highly ordered structures.