Wallace- They both thought the same exact thing about evolution 8a. Homologous Structures 8b. Analogous Structures 8c. Vestigial Structure 8d. The study of where organisms live now and where they and their ancestors used to live.
Summary of “Why Evolution is true” By: Jerry A. Coyne What is evolution; chapter I explains Darwin’s theory of evolution, which applies to all species, new species are descended from earlier forms. This means that organisms with similar characteristics are likely to have shared a common ancestor sometime in the past. The more traits shared by organisms, the closer their evolutionary relationship. This principle of “common descent” explains why anthropologists are interested in studying nonhuman animals, particularly primates (the mammalian order that includes monkeys, apes, and humans), with whom humans share the closest common ancestor. Some of our important human characteristics, such as a spinal cord encased in a bony vertebral column, and the concentration of nerve cells in a brain, are part of our vertebrate heritage, established in a common ancestor over 600 million years ago.
As a substitute, it looks for the "common ancestors" of two or more species, for example “the grandfather species that divided into two or more lineages.” New species often occur in small populations, “this view accepts that major morphological or physiological changes between a parent and daughter species can occur over a short time span.” Common ancestors are a group of organisms that has the same background. All living organisms on earth are descended from a common
MULTIPLE CHOICE 1. b 2. c 3. b 4. a 5. a SHORT ANSWER 1. A biologist would concentrate on homologous features, since they originated in a shared ancestor. 2. The animal evolved from an ancestor in which that structure was functional. 3.
Shubin shows how fin structures of fish like Tiktaalik mark the beginning of the evolution into the mammalian paw and opposable thumb structures in the hands of today’s primates. The significance behind Tiktaalik is how it proved to be the missing link which greatly shows the transition from fish who swim, to four-legged vertebrates. Neil also states that all creatures in the world are built similarly to one another. Creatures such as whales, birds, and humans have single arm bones that each lead to two others, that connect to fingers or our toes. In us humans, this shows up in the humorous, and they go through the radius and ulna into our wrist bones and fingers.
Comparative embryology B. The embryos of each of the following vertebrate Chordates, chicken( bird), human (mammal), mouse (mammal), turtle (reptile) and frog (amphibian) have the following three structures during their embryological development, a tail, pharyngeal gill arches and a notochord. None of these three structures persist in the adult forms. Thus the taxonomic basis for where these five organisms fit unites them into one phylum with characteristics that only persist in the embryonic development, not in the adults. C. The three characteristics mentioned above are key characteristics that are found in all Chordates, but in the above five examples, the characteristics are found only in the embryonic stages.
Robert added more fish to the pool to increase their genetic diversity Origin of Sexual Reproduction 10. Describe the theory of how sexual reproduction began with single-celled organisms. Some people believe that organs started years ago with two single celled creatures that shared a chance encounter in the primordial night. They meet and
“Beaked whales live in all the oceans”(Wursig 258), but some of the beaked whales “species live in the deep waters” (Wursig 258). Beaked whales nourishmostly on several squids and certain fishes(Brownell 682a). Very little is known about this group of whales for they are hardly detected and hard to find at sea (Brownell 682a). The last type of tooth whale is the Belugas. “Belugas are white or yellow-tan when their fully grown and are often called
Homo erectus evolved into Homo sapiens and had dramatically smaller brains than us. Jared Diamond also states that there was another type of the same Genus called the Neanderthals. Homo neanderthalensis had brains larger than ours; they left behind strong evidence of burying their dead and caring for their sick, but still had crude stone tools with no recognizable function. Jared Diamond states that Human History “took off” around 50,000 years ago termed “The Great Leap Forward” with evidence of history’s first preserved jewelry. Fully modern skeletons of people termed “The Cro-Magnons” had used tools of bone.
Geo 202 Ichthyosaurs Ichthyosaurs, the Greek word for fish lizard, were a marine animal far from what its name implies. They played the role of what whales, seals, and dolphins play in today’s marine ecosystem. From fossil records, geologists can tell a lot about the life ichthyosaurs lived throughout the years it roamed the seas, including their body structure, how they reproduced, what they ate, where they lived, and much more including their extinction. Based on fossil evidence, the ichthyosaur first appeared around 245 million years ago. Although earlier forms had a sleek, lizard like body, most had a body structure that most resembled modern day mammals (Perkins).