Begum Juma The Vertebrate Transition To Land Blank PDF

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The Vertebrate Transition to Land Student Handout Name: Juma Begum 1. The Origin of Tetrapods As you might know, tetrapods diverged from ancestors that lacked many features found in terrestrial animals. How did paired limbs arise? Did they arise from fish? Tiktaalik is an extinct species that many feel represents the transition from lobe-finned fish to amphibians. Click on the link on your UBlearns LECTURE site (Lab 7 folder) to the video on Great Transitions: The Origin of Tetrapods. Watch the following two video segments: a) beginning to 5:21, and b) 12:56 till the end. (The video is only 17 minutes. Feel free to watch it all. It’s COOL!!!) a. There is a common skeletal architecture inside the limbs of most tetrapods. What is the pattern of shared bones? The common structure of the limbs of the tetrapods are due to the common shared heritage of all the tetrapods and the pattern of development that was laid down by the ancestors. Pentadactyly is the evidence of having five digits and that was present in the ancestral lineage of the tetrapods that was passed down to them and thus they had a shared structure of limb development. The presence of five digits is the homologous organ that was passed down and gave rise to divergent evolution where the same common ancestor diverted the structural functioning onto various other uses.

b. Are tetrapod limbs homologous or homoplasious? Homoplasious

c. List at least two fish-like and two tetrapod-like features found in tiktaalik. 1. Fish-like: 1. They had fins and thin ray bones 2. . They had scales

2. Tetrapod-like: 1. . They have necks and a flat-head. 2. . They have ear notches and ribs capable of bearing weight.

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d. Ichthyostega is another genus of extinct animals that is closely related

on Ichthyo stega and list at least two fish-like and two tetrapod-like features found in these species. Then copy and paste the link of your source in the space provided. 1. Fish-like: 1. a small dorsal fin along the margin of its tail 2. preopercular bone in the cheek region (which serves as part of the gill cover in fishes) 2. Tetrapod-like: 1. Series of robust bones supporting the fleshy limbs 2. strong ribs and lack of gills 3. Link: https://www.britannica.com/animal/Ichthyostega 2. List the three extant groups of amphibians. 1. Salamanders: Members of the order Urodela including salamanders and newts, have long bodies and tails. Most also have four legs. Both adults and larvae are carnivores.

2. Frogs and Toads: The most obvious feature that members of the order Anura share is their ability to jump. Frogs tend to have long legs and make lengthy jumps, whereas the relatively short legs of toads limit them; the short hops, adult frogs and toads lack tails. 1. 3. Caecilians: The least known of the amphibians are the caecilians, members of the order Apoda. Caecilians are legless animals that live in water or burrow in moist or sediment, feeding and small invertebrates such as termites. Many have fish like scales embedded in their skin.

3. Challenge: The body dries out a. Two of the links on the assigned list of readings will take you to descriptions of amphibian skin and reptile skin. Based on those descriptions, identify the images below as amphibian skin or reptile skin.

Reptile

Amphibian

b. Using information from the links you have open, select the correct term

or fill in the blanks with regards to properties of amphibian skin and reptile skin. Amphibians are animals Cold blooded Animals Amphibian skin is unique because it is moist and Thin not watertight like amniote skin (including reptiles). Another feature of amphibian skin is that it remains moist. In order to retain moisture, they secrete via glands in the skin. Reptile skin is waterproof, like all amniotes. c. Write one additional adoption amphibians use to stay moist. One of the adaptations made by amphibians to their survival in aqueous environment is keeping their skin moist and slimy. Because of mucus layer amphibians always feel their skin as moist and slimy. This mucus allows the skin to maintain the moisture that the amphibious animals need to breathe and remain hydrated. Not all amphibians, however, are slimy. Depending on their habitat, amphibians adapt a wide range of strategies to keep their skin moist and supple.

2 Lab 7: The Vertebrate Transition to Land 4. Challenge: Gravity collapses large organisms With the move onto land, the spine had to adapt to support limbs. It also had to resist bending in some places, while increasing mobility elsewhere. The following all relate to challenges related to coping with gravity. a. The pectoral and pelvic girdle became larger and stronger in amphibians. List any two adaptations that allow pelvic and pectoral girdles to help resist gravity. 1. Pectoral and pelvic girdles became larger and stronger. 2. Limbs became oriented in a partially vertical direction.

b. What is an advantage to amphibians of partially vertically oriented limbs? The vertical orientation of the limbs allows the body to be lifted off the ground.

c. Which adaptation in vertebrae helps to act as the main structural support in amphibians? Interlocking vertebrae (The bones are fully ossified and the vertebrae interlock with each other by means of overlapping processes). It forms a strong horizontal column for body support.

5. Challenge: Exchange of respiratory gases only functions in water a. Most amphibians exchange respiratory gases with Lungs in the larval ill i i d lth d t d

b. Most amphibians have a moist skin, which helps to draw oxygen through the skin. This kind of respiration is called Cutaneous They can also respire through the buccal cavity. This is called buccal pumping c. List at least two structural changes that assisted with the ventilation of lungs. 1. In order to draw air into its mouth the frog lowers the floor of its mouth, which causes the throat to expand. Then the nostrils open allowing air to enter the enlarged mouth. 2. Then the nostrils open allowing air to enter the enlarged mouth.

6. Challenge: Gametes dry out and may not disperse properly a. Amphibian eggs are anamniotic b. Amphibian eggs readily dry out and die if not kept moist. List any two solu-tions to this issue. 1. The egg must be laid in the water or a very damp location. 2. Eggs are usually covered in a jelly-like substance.

7. Challenge: Senses are suited to water, not air a. List the feature in amphibians that replaced the role of lateral line (used to sense vibrations under water) in aquatic animals. Neuromast or sense hillock. It is the sensory organ present in place of the lateral line which helps in sensing the vibrations in water for the amphibians. It consists of a cluster of peer shaped sensory cells.

b. Name any two senses that are highly developed in amphibians, and which help them to find food. 1. Olfaction or smelling is a way of sensing food by the amphibians which is done by the olfactory cavity present in them. It is a chemosensory process of finding food. 2. The amphibians consists of vibration sensing organs similar to lateral line called sense hillock, which determines the kind of food nearby the organism.

8. Research activity a. Pick any topic related to the vertebrate transition to land. This could be related to any tetrapod, not necessarily only amphibians. Find one reputable online source about your topic. Copy and paste the url you find here and write one sentence about why you picked the topic. M t

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Link: https://www.frontiersin.org/articles/10.3389/fcell.2018.00070/full I choose this topic because in this article they talk about how Forelimbs and skulls became modified in advance of hind limbs, adapted for supporting the head and front of the body out of the water, They probably in connection with air breathing.

b. Print out one page of representative information about your topic and attach it to this document to turn in.

4 Lab 7: The Vertebrate Transition to Land...