Worksheet 3

Question 1

What is macroevolution?

Answer 1

Macroevolution studies evolutionary changes at the species level or greater. Examples could involve a study of fossils of different ancient horses and look at changes, such as larger teeth, decreased toe numbers and increased sizes across many species.

Question 2

What is microevolution?

Answer 2

Microevolution studies evolutionary changes within the same species. Differences between dog breeds could be a focus of such studies. Or, variations within the human species on specific gene sites.

Question 3

What type of selection was used for the Siberian Domestic Fox experiments? What was accomplished in either domestication or increased aggression?

Answer 3

Artificial selection. In both selection for either increased aggression or tameness (domestication) the researchers discovered that both results strongly based on genetics.

Question 4

What might the domestic fox experiments support about genetically linked behaviors for tameness vs. aggression in other animal species and humans?

Answer 4

These experiments have experimental support that minks and rats share the same genes for tameness and aggression as the foxes have. This is strong support that many mammals (and perhaps other animals) have these shared genes, which influence behavioral temperament and socialization. Speculations, and some genetic and psychological studies, support that humans likely have genetic regulations for temperament and perhaps empathy and socialization.

Question 5

How old is the earth supported to be? What did most people think the age of the earth was before Darwin’s time?

Answer 5

4.6 Ga (billion years old). Radio isotopic dating using Uranium238 breakdown, which has a half-life of 4.5 Ga.

Before Darwin’s time most considered the earth to be young, measured in 1,000’s of years. Many considered literal biblical interpretations, and one of the most influential was Arch Bishop Ussher in the 1600’s who, using biblical listings of generations, calculated a creation date for the earth at 4004 BC (October 23rd).

Question 6

What are some things about Darwin’s childhood?

Answer 6

What did Darwin enjoy as a child and dislike as a child?

Enjoyed

Disliked

Horse riding
School
Shooting
Fishing
Playing with siblings and cousins

Question 7

Who was John Henslow to Darwin?

Answer 7

Botany professor who took Darwin under his guidance and instructed him with proper collection and data gathering in the field. He also asked Darwin to serve as naturalist on board the HMS Beagle after graduation.

Question 8

Who was Alfred Russel Wallace?

Answer 8

– A fellow naturalist, who also traveled widely (South America and the West Indies = Indonesia). He came up with the theory of natural selection independently from Charles Darwin and wrote Darwin about his idea. They co-published together on this in 1858.

Question 9

What did Charles Darwin and Alfred Russell Wallace do in common as children?

Answer 9

Both enjoyed beetling, collecting beetles. This was a hobby that helped to train each of them for later scientific collecting of specimens and identification of them.

Question 10

Where did Alfred Russell Wallace go to study animals (2 places):

Answer 10

South America for 2 years and the West Indies for 14.

Question 11

What are the requirements for natural selection?

Answer 11

Inheritable variation in traits.
Competition for limited resources.
Differential survival and reproduction.
Time = multiple generations of time.

Question 12

What are the requirements for natural selection?

Answer 12

Increases or decreases in inheritable traits in populations over time which adapt them to the specific environments.

Question 13

What is the result or outcome of these requirements?

Answer 13

Fossils – Tiktaalik, a “missing link” or transitional form between lobe finned fishes and early tetrapod (amphibians) 375 million years ago. Ancestors of whales, such as Durodon, an 35 million year old ancestor which still had hind limbs (as flippers) and Ambulocetus, an earlier 48 million year old ancestor, which could swim and also walk onto land. Archaeopteryx, the first bird, which has both reptilian (dinosaur) traits and modern bird traits.

Answer 14

Artificial Selection – Human selected traits in domestic species. Examples include dog breeds, cows with more milk, and many apple strains.

Answer 15

Comparative anatomy

Comparison of the physical traits of various animals supporting traits that are modified from common ancestors. An example includes the same bone sequences of terrestrial vertebrates for forelimbs and hindlimbs.

Answer 16

Embryology

Studies the similarities and differences in development of various animals and supports a similar developmental sequence, which supports and common history of the various animal groups.

Answer 17

Biogeography

The specific distributions of animals and plants around the earth, which highlights their specific evolutionary histories in different locations. Why are kangaroos only native to Australia and New Guinea? Camels evolved in North America, but migrated to South America and Asia and Africa.

Answer 18

Molecular

Genetic and protein comparisons of different species which also supports a common history. The closer two species are in an evolutionary split, the closer their relative genetic sequences are.

Answer 19

Molecular evidence was not available till the 1960’s and later.

Answer 20

Natural Selection – Populations increase traits that are selected for by specific environmental factors. Faster predators in cheetahs, taller plants to shade out others and capture light, bacteria that are antibiotic resistant are all examples of this.

Answer 21

Mutations – Base pair changes in DNA, these do occur but are random and rare. Approximately 1 per one million. This is also considered the ultimate source of genetic variation for evolution.

Answer 22

Migrations – Dispersal of individuals between populations which have distinct traits and bring these to other populations via gene flow (interbreeding).

Answer 23

Small Populations – Are subject to random genetic changes due to chance influences. This will change the gene frequencies at random. The northern elephant seals lost significant genetic variation when their populations crashed, due to hunting, just over a century ago.

Answer 24

Non-Random Mating – Is produced by male competition for mates and female choice for specific traits in the males. This, which Darwin described as sexual selection, produces gender specific differences. For example, the bright colors of male birds (or peacock spiders) as opposed to the females.

Answer 25

1) mutations

2) gene flow (migrations between populations

3) Crossing over (meiosis I, prophase I)

4) Independent Assortment of Non-Homologous Chromosomes (meiosis I, metaphase I)

5) Fertilization

Answer 26

Beneficial – increases survival or reproduction
Detrimental – decreases survival or reproduction
Neutral – no effect on survival or reproduction – most mutations are neutral

Answer 27

Cancers

Answer 28

The formation of new species from changes in a population.

Answer 29

When two populations are unable to reproduce together, they may be considered separate species, or in the process of becoming so.

Answer 30

Dogs and wolves can hybridize back and forth repeatedly. Horses and donkeys can hybridize, but it generally dead ends with the mule, a healthy but sterile offspring.

Answer 31

A molecular biologist/biochemist who produced the first molecular tree of life based on specific base sequences in different organisms.

Answer 32

Carl Woese’s research supported three large groups of life, or domains: the Archaea, the Bacteria and the Eucarya.

Answer 33

The genus and species levels. The genus is capitalized and both are underlined or italicized. Humans = Homo sapiens

Neanderthals = Homo neanderthalensis

Answer 34

Structures that were once larger and more functional. Now reduced and with limited functions. The appendix and our internal tails are two vestigial traits in humans.

Answer 35

About 60 to 65 million years ago.

Answer 36

Mobile limbs
Grasping digits
Opposable digits
binocular vision
Low reproductive rate and lots of parental care (long development time of young)
Large brains
Complex social structures

Answer 37

Living in trees, or arboreal life, that our common ancestral primates had.

Answer 38

Around 22 million years ago.

Answer 39

Between 6 and 8 million years ago.

Answer 40

Vestigial, internal tail remnants.

Larger brains than other primates

Longer development time and parental care in infants.

Answer 41

Bipedalism

Answer 42

Migrate out of Africa and into Asia, Australia, the Middle East and Europe.

Answer 43

“Ardi” was an early hominid, between 5.5 and 4.5 million years ago (Ma), which had transitional traits for bipedalism. Though Ardi was bipedal, she was less advanced than later hominids. Ardi had an ape-like brain and skull, though small canines, which is a trait of hominids. The foramen magnum opened straight down, supporting bipedalism. Her feet were flat, not arched and had an opposable big toe. Shorter legs and longer arms with very long fingers for climbing. The fingers did not have any evidence for knuckle walking like apes though. Ardi could both walk (not as efficiently as later hominids) and climb. Studies of her diet support a gatherer diet of many plants including lots of tubers (starchy root plants).

Answer 44

“Lucy” was the most famous of these species, living about 3.4 Ma. They were bipedal, gatherer, ate raw foods, brains about same as modern apes, and were small in size (about 3 and a half feet tall). More advanced in bipedalism than Ardi with a big toe now aligned forward and no longer bipedal and the beginning of an arched foot and shorter fingers than Ardi.

Answer 45

Lucy is one of the most famous of Ardipithecus species. An early hominid with relatively advanced traits for bipedalism, but a small ape-sized brain. Not a tool user. She was named after the Beatles song “Lucy in the Sky with Diamonds”.

Answer 46

Known as nutcracker man. Was extremely specialized for consuming many raw plants. Had large teeth, jaws, jaw muscles and a sagittal crest adapted for extensive chewing. Brain about the size of a modern ape still. Contemporary with Homo habilis.

Answer 47

Larger brain than earlier hominids. First stone tool user. Was a scavenger and gatherer who ate bone marrow and plants. Found around 2.4 Ma.

Answer 48

Homo ergaster is an African hominid that is considered a direct ancestor to our own species with a larger brain and more complex stone axe tools. They were the first true hunter gatherer hominids living around 1.8 million years ago and the first fire users. Though a smaller brain than our own, they did have the first hominid body that was as large as our own with long legs for efficient walking and hunting.

Answer 49

Homo erectus and Homo ergaster (African) were tool users and were the first hominids to use fire for cooking foods. Had bigger brains that Homo habilis. Also H. erectus is related to H. ergaster but was the first hominid to live in Asia.

Answer 50

The “Hobbits” which were a descendant of Homo erectus but smaller in size and smaller in brain. Only about 4 feet in height. Still tool users and fire users. Located in Indonesian islands. Survived till perhaps 18,000 years ago.

Answer 51

At 800,000 years ago, this was a later hominid, descended from Homo ergaster. Found through Europe and central Asia and the Middle East. May have given rise to Homo sapiens, but definitely a direct ancestor of the Neanderthals.

Answer 52

Both are descended from Homo ergaster though Homo sapiens evolved in Africa and Homo neanderthalensis evolved in Europe, Central Asia and the Middle East. Both had similar brain size and complex societies with many tools and fire use. Though there are a number of physical differences (Neanderthals were stronger, larger boned, more adapated to the Ice Age) we were similar enough that Homo sapiens ancestors who migrated into Europe and Central Asia hybridized with Neanderthals.

Answer 53

Our own species, which originated by 600,000 years ago in Africa. Began migrating out of Africa in two waves. The first around 100,000 years ago, leading to coastal Asia and Australia by 60,000 years ago. Second wave into the Middle East, Europe and Asia by 40,000 years ago and later into the New World by around 17,000 years ago. Hybridized on both migrations with Neanderthals and eventually outcompeted them.

Answer 54

Around 1.6 Million years ago, with Homo erectus who migrated out of Africa. Studies do not support that Homo erectus was our direct ancestor, rather Homo ergaster, the African ancestor of Homo erectus, was also our ancestral species.

Answer 55

Wrangham hypothesized that cooked foods – starting as early as 1.8 million years ago – made several adaptations to our digestive system – smaller jaws, jaw muscles, teeth, stomach and large intestines. Cooking also pre-processes foods to make them easier to digest and absorb nutrients. The extra nutrients and reduced energy needs for the digestive system were then redirected into greater brain size adaptations.

Answer 56

Sweating – we can sweat more than any other mammal – helps us cool off, which are ancestors used when hunting in the heat of the daytime in Africa – and elsewhere.
Vestigial or reduced body hair (in size and length). This also helped us be more efficient in cooling off.
Super fat, or rather high fat reserves – needed when our hunter gatherer ancestors didn’t have foods to eat and could then survive up to several days or a week or more on fat reserves when needed. Women also require extra amounts for the nutritional expenses of reproduction and nursing.
Endurance – being bipedal we have many adaptations that make us energetically efficient for movement – we use half the energy that a chimpanzee uses to move the same distance. This endurance also helped us to track and put into a trot or run the many herbivores that we hunted.
Tracking abilities – no other species can recognize the abstract symbolism of tracks of other species and connect what it means for hunting, understanding their herd structure, and individual variations.
Fire
Large brains and complex social interactions
Stone tools
All of these were vital to survival and reproduction. Yes, we still have them. Do you still use them though?

Answer 57

They ate high amounts of animal fats and the entire animal, including many organ meats. They also ate far less processed foods and lower amounts of starchy carbs and sugars. We are most adapted to the ancestral or ethnic foods that are more diverse in nutrient density (high animal proteins/fats and a variety of plants). Not so adapted to the low nutrient dense processed starchy carbs, vegetable oils and sugars.

Answer 58

Migrating to new lands. 2. Trade. 3. New Technologies (starting with agriculture). All of these have provided more resources to our now global population of over 7.7 billion.

Answer 59

The carrying capacity is the limit of resources for any species, including our own. These limits can include food, water, space, nutrients and other factors. The carrying capacity is not a constant and can either increase or decrease with changes in the environment. For humans, our current population can only be sustained by our increasing technologies. Our carrying capacity can be decreased by environmental problems, such as overgrazing, overfishing, desertification and climate change.

Answer 60

Increased education, especially focused to involve more girls.
Increased health care, especially focused towards young women and children (reducing childhood mortality.
Increased economic assistance in microloans for small businesses. With a focus of many of these to women to gain economic independence.
Increased family planning education.
Increased availability of birth control measures (mainly condoms).
Through these actions Thailand lowered the average number of children per couple from 6.4 to 1.9 in a decade.

Answer 61

On Henderson Island and Pitcairn Island they went extinct. On Mangareva and Easter Islands the populations crashed, but survived at a lower carrying capacity.

Answer 62

Friendly neighbors for trade – boosts survival and K (carrying capacity)
Environmental destruction reduces K
Climate change reduces K
Aggressive interactions – war – reduces K
A society’s response to environmental issues is always critical to long term survival. If this is ignored, it will limit long term survival.