Lemurs (Prosimians/Strepsirhini) -  Lemurs are native to Madagascar and the Comoro Islands. Madagascar has a harsh seasonal climate that the Lemurs have had to adapt to. Specific things that the Lemurs do, help them to live under these harsh conditions. They occasionally store fat, hibernate when food sources are low, and have strict mating seasons. Most Lemurs live all of their life in the trees. Many of the larger species of Lemurs do live on the ground. Lemurs are usually active during the day and are very social. They live in family groups and the females have dominace over the males. Lemurs are forest creatures and many species live in Madagascar’s tropical rainforests, but some live in the dry deciduous forests. The lemurs’ muscular legs are adapted for jumping and their strong hans and fingers help them to climb trees easily. Lemurs are usually very small but they do vary in size depending on the species that you are looking at.

 The pygmy mouse Lemur is the smallest species 

of Lemurs. The pygmy mouse Lemur is actually 

the world's smallest primate. Their body length 

is usually only about 2.4 inches long with a tail 

length of up to 5.4 inches and only weigh about 

1.1 ounces. Lemurs can range anywhere from 1.1

 ounces to around 20lbs. The tails of all lemurs

 are usually longer than their body.

Most species of lemurs do exhibit 

sexual dimorphism, or different 

coloring between males and females. 

Both male and female ring-tailed 
lemur's have a fluffy, black-and-white 
striped tail. The only Lemur that 
is completely black is the male black 
lemur. The females have a white ruff 
around their black face and a white 
chest. The rest of the female's body 
is reddish brown. Both the male and 
female mongoose lemurs are a 
gray-brown color but the females 
have white cheeks and neck and the
males have red cheeks. 


Lemurs have fairly no competition with any other species of primates in Madagascar. They do, however, have competition amongst themselves. When Lemurs mate, they either have multiple male partners throughout one night, or the female chooses to have one male partner. In a study done, the larger lemurs had multiple partners while smaller lemurs decided to have only one. There is no precise answer to if the size of Lemurs has anything to do with their mating process or not. I believe the size of a Lemur does help them to move around the trees much quicker and faster. Also having a smaller body means that they require less food and nutrient. This makes it easier for them to survive in the conditions in Madagascar. 

Spider Monkey (New World Monkey/Platyrrhini) - Spider monkeys are new world primates that, most species, live in the tropical rain forests of Central and South America and live as far north as Mexico. Spider monkeys have long, lanky arms that help them to move from branch to branch in the rain forests. They also have gripping tails to aid in this. The spider monkeys spend most of their time up in the trees. They live in the upper layers of the rainforest's and forage. Due to their size, they require large tracts of moist evergreen forests. Black-headed Spider Monkeys are the largest spider monkey. They are an average weight of 24 lbs for males and 21.3lbs for females. 

Spider monkeys are not characterized by sexual dimorphism. The males and females are all about the same size and colors. There are a few differences between younger spider monkeys and their elders but not between the males and females. Not having a larger body or different colored hair or fur is completely fine for the spider monkeys since they do not have to worry about competition between each other. 

Baboon (Old World Monkey/Cercopithecidae) - There are five different species of Baboon's, all of which live in Arabia and Africa Baboons usually prefer savanna and other habitats that are semi-arid. A few baboons live in tropical forests. Baboons are ground dwelling animals and are found in open savannah, open woodland and hills across Africa. They do not have grabbing tails but do climb trees to eat, sleep and look out for danger below. In all species of Baboons, there is pronounced sexual dimorphism. It usually shows in the size of the Baboons when males are compared to females. Usually the males are larger. Specifically, the Hamadryas Baboon males are double the size of the females. The males fur is a silver-white color and the females are brown in color. The males also develop a large white mane and the females are mane less. 


Male Baboon's body measure up to 3ft and weigh between 40-70lbs and the female's body measures up to 2 ft and weigh between 20-35lbs. The tails of the baboons add about 1.3-2ft of extra length to the baboons.




The size of the male baboons compared to the females makes the males the stronger of the two. The males use their size to protect their females and themselves.




Gibbon (Lesser ape/Hylobatidae) - Gibbon's are a very small and lightweight animal.They spend most of their lives in trees. They are very acrobatic and fast primates. Gibbons are distributed in wild in the tropical and subtropical rain forests of Southeast, South and East Asia. They are also currently found in small populations in China, Laos, Vietnam, Cambodia, Thailand, Bangledesh, Northeast India, Myanmar, Malayysia and Indonesia. 


Gibbons are not sexually dimorphic in size. The males and females are about the same size. In some species, the Gibbons do have different colors from male to female. Since Gibbon's are generally small primates, they are also referred to as the "lesser apes". Most adult gibbons are only around 3 feet tall standing upright. They average around 12-22lbs in weight. The only Gibbons that show sexual dimorphism in size are the Siamangs. Since Gibbons are so agile and live amongst the tops of the trees, they do not need to be large to protect themselves, they are fast instead.

White-cheeked gibbons do have different fur colors. The males have black fur and skin with white fur on their cheeks. The females are golden or a reddish buff-colored and have black faces and dark brown or black fur on top of their heads. They also have white fur in a halo shape around their faces. 

Chimpanzee (Great ape/Hominidae) - Chimpanzees live in social communities with several dozen different animals. They can habituate themselves to African rain forests, woodlands and grasslands. Chimpanzees are found across a central band of the continent of Africa. Generally, chimpanzees are rain forest creatures. They span out around 21 different African countries from the west coast of the continent east through the vast central-African nation of Congo to the western reaches of Uganda, Rwanda, Burundi and Tanzani. Chimpanzees eat and sleep up in trees but they do spend most of their time on the ground. As long as Chimpanzees have access to forests that they can take shelter in and search for food, they can live in drier areas that have less trees. Male chimpanzees are larger than female chimpanzees. The average male chimpanzee weighs around 140-160lbs and the females weigh up to 110lbs. They are about the same height when standing upright. They live in a male dominated social structure. The males definitely have less tolerance towards other unfamiliar male chimpanzees, where-as the females don't.  

Each different type of primate definitely had a direct effect on their sizes from their living conditions. They use their body size to protect themselves either against each other or other species. The sexual dimorphism that is apparent in the different animals, seems to be more prominent in the larger animals. The smaller the animal, the less sexual dimorphism seems to be there. I also think that the smaller animals are safer amongst the high tree tops and do not need to protect themselves from anyone else. They have less competition so they haven't had to evolve as much when referring to their body sizes.  

Sources :

http://www.lemurworld.com/lemur-anatomy.html

http://animals.nationalgeographic.com/animals/mammals/baboon/

http://nationalzoo.si.edu/Animals/Primates/Facts/FactSheets/Gibbons/default.cfm

http://www.enchantedlearning.com/subjects/apes/chimp/

A) Two different species that posses homologous traits would be the whale and a human. Sounds crazy right? The front fins of a whale compared to the bones in the arm of a human are homologous. 

B) The bones in both of these animals, are basically the same bones. The bones in the human arm are going to be a different size from the bones in a whales front fins. They both serve for a function even though they are a slightly different function. The whale swims and the human uses their arms for everyday activities and to grab things. There are different things that could be made better or perfect in the human arm or whale fin but the structure that they have, is perfect for there species. They only need to compete for greatness amongst each other, not other species. A whale fin would not do any good on a human body and same goes for a whale to have the human arm structure because it would not be as great for swimming. 

C) As it is said, the ape is the common ancestor of the early human species. The ape was also the first species to possess "hand" structures. At that point in time, the apes used their arms and hands to walk on, where as today, the human uses them for a different purpose. 

A) Two animals that posses analogous traits would be a spider and a elephant leg. Both have "legs" but both species are from different origins. The legs of both species are also used for different purposes and work differently.

B) Spiders are from the insect species and elephants are from the mammal species. The legs of a spider are jointed leg segments and are called podomeires where as the elephants legs are composed of bones that are jointed together with ligaments. The legs of a elephant rotate in the socket as they walk. Elephants also apply power independently to each leg as compared to other animals applying power to their rear legs to drive them. 

C) I think the ancestors of the first insects did not have legs where as the first ancestors of mammals, did have legs. I think that enviromental pressure caused spiders to have legs to coupe with the pressures and get them to move around faster. 

Protein Synthesis DNA strand

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Thomas Malthus

I feel that Thomas Malthus had one of the strongest positive influences over Darwin's development of his theory of natural selection. 

Malthus' theory on population was very simple. It was based on the assumption that the power of the population is much greater than the power of the Earth to provide subsistence for man. Basically, if man kept reproducing at their capable rate, there would come a point in time when there would not be enough resources to feed the people. Yes, there would be enough people to make food but not enough of the resources used to make the food. This would lead to a famine or other disasters. Malthus said that a population could only remain within its resource limitations by "positive and preventative checks." He claimed these positive checks to be things like war, disease and starvation. The preventative checks that could prevent overpopulation were things such as late marriage, celibacy and birth control. These positive checks raised death rates and the preventative checks lowered the birth rate. Malthus' theory on population made people realize that there was a point that would come when we would run out of resources if everyone and thing reproduce at their capacity.

• All organisms have the potential of reproducing exponentially. Two rabbits are roughly capable of producing approximately 200 rabbits in their lifetime. Imagine if all 200 baby bunnies had 200 hundred more baby bunnies… and so on… and so on… That is exponential growth that has the potential of having us up to our eyeballs in rabbits. But we aren’t up to our eyeballs in rabbits, are we? Why not? This question is the starting point of Darwin’s work.

Malthus taught us that positive and preventative checks were needed to keep us from overpopulation. In the speaking of bunnies, there would not be enough food for the bunnies to survive. The mothers clearly need enough food and shelter to be able to reproduce. At a point in time, the natural positive checks would start to play a part. The bunnies would starve and die. A disease from a deceased bunny could spread and cause further deaths. 

• Organisms with better access to resources will be more successful in their reproductive efforts. The rabbits with more food and water and shelter will reproduce more offspring than those rabbits with fewer of these resources.

Malthus used the idea of positive and preventative checks in his theory often. Organism's that had the access to food would not die from starvation. Ones that did not have as good of access could possibly die from starvation showing us a "positive check". People with the capability to obtain birth control, would not be reproducing, showing a preventative check. There are so many different examples to prove his theory. 

I personally do not think that Darwin could have developed his theory of natural selection without the influence of Thomas Malthus.  After Darwin read Malthus' work in 1838, he realized that when animals were in their struggle to survive, they would retain the favorable features that they had, that would help them adjust to their new environment and basically forget the other traits and features that they had. This is what the Theory of Natural selection was born from. I feel like without Darwin reading Malthus' work, I do not believe Darwin's theory would be quite the same.

The attitude of the church very much so affected Darwin and his publication of his book On the Origin of Species. At that point in time, it was a big deal to be questioning the church. The church was looked at as the highest form of belief. Darwin's work would have everyone questioning the church and it's teachings. It was a risky move for Darwin to even think about questioning or going against the church.