section 7 and 8 bio1309

How old are Tiktaalik?

375 MYO

Marsupials

Marsupials are an infraclass of mammals living primarily in Australasia and the Americas. A distinctive characteristic, common to most species, is that the young are carried in a pouch. Well-known marsupials include kangaroos, wallabies, the koala, possums, opossums, wombats and the Tasmanian devil.

The major groups and their synapomorphies are:

Tetrapoda - 4 legs Amniota - Amniotic egg Lissamphibia (living "amphibians") - Teeth on pedestals Synapsida - Lower temporal opening (see below) Sauropsida - Suborbital fenestra (see below)

Carboniferous Period

The Carboniferous Period lasted from about 359.2 to 299 million years ago* during the late Paleozoic Era. The term "Carboniferous" comes from England, in reference to the rich deposits of coal that occur there.

the amniotic egg

The amniote egg allowed amphibians to place their eggs on dry land instead of in water. The water, amniotic fluid, was in the egg. ex of animals who lay amniotic eggs are turtles, lizards, birds, dinosaurs, mammals

What was significant about the Acanthostega fossil that Clack found?

The first fish to have hands or the first specie to have hands on earth

evolutionary fitness

The probability that the line of descent from an individual with a specific trait will not die out. Biologists use the word fitness to describe how good a particular genotype is at leaving offspring in the next generation relative to how good other genotypes are at it. ex. So if brown beetles consistently leave more offspring than green beetles because of their color, you'd say that the brown beetles had a higher fitness.

importance of transitional fossils

Transitional fossils are important because they are visual evidence of one type of animal evolving into another type of animal. A transitional fossil always contains features of one type and features of another. For example, Archaeopteryx is a transitional fossil that is a cross between a dinosaur and a bird. It has a bony tail, teeth, and claws like a dinosaur, but it has feathers and is able to fly like a bird. It is an important link in the evolution from dinosaurs to birds.

Explain the relationships among these terms: DNA, chromosome, gene, protein, allele.

a threadlike structure of nucleic acids and PROTEIN found in the nucleus of most living cells, carrying GENETIC (DNA)information in the form of genes. one of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome

vertebrate

animals with backbones member of the chordates. ex. sharks, lampreys and rays and bony fish.

tetrapod

any animal with four legs but this group also includes many animals that don't have four feet. That's because the group includes all the organisms (living and extinct) that descended from the last common ancestor of amphibians, reptiles, and mammals. with four feet.

sexual reproduction

the production of new living organisms by combining genetic information from two individuals of different types (sexes). In most higher organisms, one sex (male) produces a small motile gamete that travels to fuse with a larger stationary gamete produced by the other (female).

recombination

the rearrangement of genetic material, especially by crossing over in chromosomes or by the artificial joining of segments of DNA from different organisms.

Is this phylogenetic tree based on a hypothesis or a theory?

thus, the result of phylogenetic studies are hypotheses about the evolutionary history of taxonomic groups or their phylogeny.

What structures are found inside the fin of Tiktaalik?

inside the fin are many of our own arm bones: it has an upper arm bone, it has a lower arm bone, it has forearm bones, it has a wrist, it has finger-like things. It is a fin that is able to support the animal.

placental mammals

longer gestation, better chance for survival. Placental mammals all bear live young, which are nourished before birth in the mother's uterus through a specialized embryonic organ attached to the uterus wall, the placenta. The placenta is derived from the same membranes that surround the embryos in the amniote eggs of reptiles, birds, and monotreme. mammals. The term "placental mammals" is somewhat of a misnomer because marsupials also have placentae. The difference is that the placenta of marsupials is very short-lived and does not make as much of a contribution to fetal nourishment as it does in eutherians, as "placental mammals" are known scientifically. mostly rodents and bats( any mammal who carries their young in their belly)

Sexual selection

natural selection arising through preference by one sex for certain characteristics in individuals of the other sex. ex.extravagant and colorful tail feathers or fins are likely to attract.

What is phylogeny?

the branch of biology that deals with phylogenesis.

Explain that all living organisms use DNA in a similar fashion and explain the implications of that for the evolutionary history of life

All living organisms store genetic information using the same molecules — DNA and RNA. Written in the genetic code of these molecules is compelling evidence of the shared ancestry of all living things. Evolution of higher life forms requires the development of new genes to support different body plans and types of nutrition. Even so, complex organisms retain many genes that govern core metabolic functions carried over from their primitive past. genes can also be exchanged or "stolen" from other organisms.

role of Archaeopteryx

Archaeopteryx as a transitional fossil between dinosaurs and modern birds. With its blend of avian and reptilian features, it was long viewed as the earliest known bird. Discovered in 1860 in Germany, it's sometimes referred to as Urvogel, the German word for "original bird" or "first bird." lived around 150 million years ago — during the early Tithonian stage in the late Jurassic. It had broad wings with rounded ends and a tail that was long for its body length, which was up to 20 inches (50 centimeters) in total. It had broad wings with rounded ends and a tail that was long for its body length, which was up to 20 inches (50 centimeters) in total.

Describe the characteristics of mammals

Are vertebrates (which means they have a backbone or spine). Are endothermic. Also known as "warm-blooded," endothermic animals regulate their own body temperate which allows them to live in almost every climate on Earth. Have hair on their bodies. Produce milk to feed their babies.

asexual reproduction.

Asexual reproduction is the primary form of reproduction for single-celled organisms such as the archaebacteria, eubacteria, and protists. Many plants and fungi reproduce asexually as well.

what is the closest relative to bird

Aves was most commonly defined phylogenetically as all descendants of the most recent common ancestor of modern birds and Archaeopteryx lithographica.

Describe the function of DNA in cells

DNA does not just "help cells reproduce" it is the genetic blueprint for every living being. DNA basically stores info and tells the cell what to do. All of your genes are in your DNA.

Explain how information from the fossil record and living organisms is used to reconstruct the evolutionary history of a group of organisms

Fossils provide a unique view into the history of life by showing the forms and features of life in the past. Fossils tell us how species have changed across long periods of the Earth's history. For instance, in 1998, scientists found a fossil showing an animal at the transition from sea creature to land creature. This tetrapod had a hand-like fin, confirming a prediction of evolutionary biology. Though the fossil record does not include every plant and animal that ever lived, it provides substantial evidence for the common descent of life via evolution. The fossil record is a remarkable gift for the study of nature.

Genetic drift

Genetic drift refers to the change in a type of genes in a population because of the random nature of reproduction. In other words, when people who have the gene causing a specific genetic trait reproduce with people who do not have the gene, the gene can become more popular or totally disappear from the population. ex. Of the two pink monkeys in the world - one male, one female - the female dies, ensuring that there will never be a pure-bred pink monkey again.

what's the closest relative to frogs

Gerobatrachus

Describe and give examples of negative selection, positive selection, stabilizing selection, and balancing selection

In natural selection, negative selection[1] or purifying selection is the selective removal of alleles that are deleterious. This can result in stabilizing selection through the purging of deleterious variations that arise. ex.Negative selection therefore is probably the mechanism for the "equilibrium" phase of a species, during which a species changes very little.

Gene flow

In population genetics, gene flow (also known as gene migration) is the transfer of alleles or genes from one population to another. ex.Blue-eyed people from Sweden move to a small town in Mexico where people all have brown eyes. When they mate, some of their children now have blue eyes.

Why was the discovery of Tiktaalik roseae significant?

It is a fish that blurs the distinction between a fish and a land-living animal. telling us that this is a fish that can live in the shallows and even make short excursions on to land.

variations produced by mutations

Mutation creates slightly different versions of the same genes, called alleles. These small differences in DNA sequence make every individual unique. They account for the variation we see in human hair color, skin color, height, shape, behavior, and susceptibility to disease. Individuals in other species vary too, in both physical appearance and behavior. Mutation creates variations in protein-coding portions of genes that can affect the protein itself. But even more often, it creates variations in the "switches" that control when and where a protein is active and how much protein is made.

mutation affect on fitness

Mutation is also generally a source of defect: many mutations are not neutral but cause fitness decreases in the organisms where they arise. In bacteria, another important source of variation is horizontal gene transfer. This source of variation can also cause beneficial or deleterious effects. Determining the distribution of fitness effects of mutations in different environments and genetic backgrounds is an active research field. In bacteria, knowledge of these distributions is key for understanding important traits.

monotremes

diverged ~190 mya, egg laying, Have many reptilian characteristics, Have mammary glands and make milk, Milk is secreted onto the abdominal fur (platypus) or into a temporary pouch and licked off the skin (echidna) Poor eyesight but great sense of smell, the platypus and the short-beaked echidna are examples. meaning "one-holed", because they have just one external opening, the cloaca, for both waste elimination and for reproduction.

which came first: fish moving onto land or fish growing forelimbs

fish came on to shore first then developed legs

characteristics of Tiktaalik roseae fossils

found on Ellesmere Island, Canada, 3 feet, (lobe-finned fish) from the late Devonian period, having many features to those of tetrapods (four-legged animals). The name means a freshwater fish related to true cod.

tetrapod traits of Acanthostega .

had a fish like tail in the back, had gills inside for breathing under water, with petal shapped arms

differences in mutation

harmful=downs syndrome9getting an extra chromosome neutral=attached free earlobes helpful=sickle cell anaemia. Its carriers are anaemic but are resistant to malaria.