Download HUMAN BIOLOGY 102

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 selection occurs 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
4 MYA (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.
Homo Sapiens
There is only one genus and species of hominids, and that is Homo 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.