HUMAN BIOLOGY 102

WHY ARE YOU TAKING THIS CLASS?

During this semester, we will first talk about important molecules that you need to understand the body.Then we will talk about cells. Then we will talk about tissues.

We will spend most of the rest of the semester talking about body organs and systems.

HOMEWORK 1A DUE NEXT WEEK

EVOLUTION

Certain attributes evolve to help animals survive. In the animal kingdom size provides the strength needed for combat; a larger skull makes room for a larger brain; elongated legs ending in hooves provides greater speed to escape enemies; and durable, grinding teeth enables the animal to feed efficiently on grasses.

The Theory of Natural Selection

Charles Darwin formulated a theory of natural selection around 1860 to explain the evolutionary process. The following are critical to understanding natural selection.

1. Existence of Variations

Genes determine the appearance of an organism and that mutations can cause new variations to arise.

2. Struggle for Existence

Plants and animals compete for available resources. Only certain members of a population survive and reproduce those characteristics that give them a competitive advantage.

3. Survival of the Fittest

Natural selectionoccurs because certain members of a population happen to have a variation that makes them more suited to their own environment. For example, any variation that increases the speed of a hoofed animal will help it escape predators and live longer; a variation that reduces water loss will help a desert plant survive; and one that increases the sense of smell will help a coyote find its prey. Therefore, we would expect organisms with these traits to live longer and, consequently, reproduce to a greater extent.

Classification of Living Things

Taxonomy is that part of biology dedicated to naming, describing, and classifying species. Who are we? For humans, here is our classification

Kingdom: Animal

Class: Mammal

Order: Primate

Family: Hominid

Genus: Homo

Species: sapiens

Animals

What’s the difference between an animal and a plant? An animal can move from one place to another, they don’t get food from sunlight, and their body structure is fixed.

Mammals

Mammals are born with a placenta and produce milk for the offspring.

Primates

Primates have an opposable thumb(can touch each of the other fingers).

Good depth perception because the eyes are in front of the head.

Gestation (length of pregnancy) is lengthy.

One birth at a time is the norm.

Juvenile period of dependency is long.

There is an emphasis on learned behavior and complex social interactions.

Humans and apes are both primates. There are four types of modem apes: gibbons, orangutans, gorillas, and chimpanzees. Humans can be distinguished from modern apes by walking upright, dental features, shape of face, and brain size.

Hominids

•Make use of symbolic language (writing)

•Walk on two legs

Evolutionists say that our ancestors are Australopithecus, which evolved in eastern Africa 4MYA (million years ago). The most famous Australopithecus fossil is called Lucy (The name derives from the Beatles’ song “Lucy in the Sky with Diamonds.”). Although her brain was quite small, Lucy walked upright.

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HomoSapiens

There is only one genus and species of hominids, and that isHomo sapiens. In Latin, it means wise or rational man.

We Are One Species

Races are actually just slight differences in ethnicity that developed as an adaptation to the climate of a region. But inside, our molecules are all the same.