Evolution 1 Flashcards
What is the pentadactyl limb?
The pentadactyl limb is a homologous structure found in all classes of tetrapods, from frogs to humans. You should have completed your labelling of the pentadactyl limb for the prelab.
Using the terms provided below, label and annotate the diagram of the pentadactyl limb.
Carpals Carpus (wrist) Digits Elbow
Femur Fibula Foot Forearm
Hand Humerus Knee Metacarpals
Metatarsals Phalanges Radius Shank
Tarsals Tarsus (ankle) Thigh Tibia
Ulna Upper arm
What is a tetrapod?
A tetrapod is an animal superclass that includes all limbed vertebrates constituting the classes Amphibia, Reptilia, Aves, Mammalia, and all direct ancestors
When alive, did these skeletons walk upright or on four legs?
A- Walked on four legs and upright
B- Upright
C- Upright
How can you tell?
A’s foramen magnum is positioned in the back of the skull which indicates that the specimen used all four limbs for locomotion. B and C’s foramen magnum is positioned directly underneath the skull which indicates that the specimens used only two of their limbs for locomotion.
Which skeleton(s) that walked upright would have found it easier to walk and run long distances? Why?
Skeleton C. It has a long femur/legs, therefore, it would be able to take longer strides. This enables the skeleton to walk further and faster.
Based on your answers, as well as the information that A was found in Kenya; B in France; and C in Canada, speculate which specimen would require a zoologist, which an anthropologist, and which a forensic anthropologist to identify it. Give reasons for your answers.
A- A zoologist studies animals and their behaviour. The skeleton in A did not walk upright. It was found in Kenya, Africa, which is the cradle of humankind. It is not bipedal which puts it out of the hominid class and is, therefore, within the scope of a zoologist’s interest.
B- Anthropologist. Anthropology “
studies human beings in aspects ranging from the biology and
evolutionary history of Homo sapiens to the features of society and culture that decisively
It has a smaller skull than modern humans and was found in Europe, which makes it an early ancestor of the human species
who ventured from Africa into Europe. It ,therefore, falls into the area of study for anthropologists.
C- Forensic Anthropologist. These professionals analyse human remains to find their identities. This skeleton was found in Canada, a place where humans migrated to from Asia. The skeleton is that of a modern human and fits within the scope of what forensic anthropology studies.
Do you find the comparisons in PART B to be sufficient evidence for common ancestry? Justify your answer.
Yes. The skeletons all shared common skeletal characteristics, which shows common ancestry.
What further information would be valuable as supporting evidence for common ancestry?
Analysis of each of their genomes could shows common sequences, indicating common ancestry.
We usually assume that Homo sapiens is the most highly evolved and specialised mammal. Discuss the ways in which this statement is BOTH true and false.
They are bipedal which has advantages and disadvantages. The advantages are free hands for tools and infants, improves cooling of the body, allows a greater field of vision, and also allows for long distance travel. The disadvantages are lower back pain and it decreases the ability to climb trees.
Why do so few birds graze on leaves and grass?
Birds need a lot of energy for flight, and leaves and grass are a low energy source for them.
In a flow diagram, trace the evolutionary route of humans from the first terrestrial vertebrates to Homo sapiens. Hint: click on the frog to start. Then click on the links to groups where you think humans should belong. (8)
During construction of your flow diagram (1.) you should have reached a page titled
“Hominidae”. On the left side of the screen you will find a link to “Evolutionary nutrition”. Read
through the information and briefly describe how human nutrition has changed with time from
Australopithecus africanus to modern humans (Homo sapiens). (5)
- Omnivorous Australopithecus africanus ate mostly plants as part of their diet. This diet is supported
by their huge molars and premolars and broad jaws. They were usually opportunistic hunters.
Although they had a lower fibre intake than chimpanzees, their diets were otherwise relatively similar.
Their nutrition was more similar to that of chimpanzees than it was to that of Homo sapiens. - The diet of Homo erectus was largely composed of meat. Due to this protein-rich diet, Homo erectus
had a greater cranial capacity than Australopithecus. They were scavengers and hunters. In addition
to meat, they also ate foraged vegetables, fruits, shoots, and roots. - The “caveman diet,” which included a variety of plants, fish, and meats, was what Homo neanderthalensis ate. They ate a lot of vegetables and fatty meats. They rarely scavenged, in contrast to their forefathers, who were primarily hunters. Compared to Homo erectus and Australopithecus, they ate more meat. Their higher cerebral capacity was paralleled in this growth.
- The most diversified diet belongs to homo sapiens. Wild game, vegetables, nuts, and fruits make up
their diet. Homo sapiens engaged in organized agriculture, in contrast to their forebears. They started
using monoculture, and they ate a lot of crops. Depending on the particular organism, Homo sapiens
may be fruitarian, omnivorous, vegetarian, or carnivorous. - In general, the increase in meat intake is a common trend across evolutionary time. Diets became
more varied as well and a wider range of foods became available due to new means for obtaining it.
Trends moved from foraging to scavenging, to hunting, to agriculture.
