o A. Invagination of plasma membrane
o B. Endosymbiosis
Symbiosis : An ecological relationship between organisms of 2 different
species that live together in direct contact.
How did this get started?
prey or parasite
Extinction Is Forever
o Passenger pigeon was hunted to extinction by 1900 when a young boy in Ohio
killed the last in the wild
o In 1813, John James Aududon saw a huge flock that took 3 days to pass and
was so dense it darkened the sky
o Many uses from f
Endless Forms Most Beautiful
o A new era of biology began in 1859 when Charles Darwin published The Origin
o The Origin of Species focused biologists attention on the great diversity of
Darwin noted that current species are descenda
o Natural populations of a species typically are not completely isolated, but
instead exchange genes with one another to a greater or lesser extent
o Gene flow, if unopposed by other factors, homogenizes a population
o Models of Gene flow
o Between plants and animals
o A relationship develops between two organisms such that, as they interact with
each other over time, each exerts a selection pressure on the other.
o Evolution of each becomes interdependent on that interaction
o Infinite populations
Gene frequencies remains constant over generations
o What if populations are finite?
o Genetic drift versus
Selection: fitness of alleles differs
Drift: fitness of all
o Heredity is the passing on of characteristics or traits from one generation
to the next. It is the reason why offspring look like their parents. It also
explains why cats always give birth to kittens and never puppies. The
process of he
Origin of Life
o Aristotle (384 322 BC)
Proposed the theory of spontaneous generation
Also called abiogenesis
Idea that living things can arise from nonliving matter
Idea lasted almost 2000 years
o Spontaneous Generation
For centuries, people based
o Organisms are classified into a hierarchical classification that groups closely
related organisms and progressively includes more and more organisms.
The species is the basic biological unit around which classifications are
Charles Darwin (1809-1882) Sailed around the world 1831-1836
o 2. What did Darwins Travels reveal
The diversity of living species was far greater than anyone had
These observations led him to develop the theory of evolution!
o 3.How d
Evidence for Evolution
o The Fact of Evolution
Evolution-the progressive change of organisms as they descend from
ancestral species-is a fact. By now, the evidence for it is overwhelming
It is of such obvious clinical significance in me
o What Are Mutations?
Changes in the nucleotide sequence of DNA
May occur in somatic cells (arent passed to offspring)
May occur in gametes (eggs & sperm) and be passed to offspring
o Are Mutations Helpful or Harmful?
Mutations happen regul
Habitats and Adaptations
A Habitat is the place where a plant or animal lives. Every living thing has
a place which can be called its habitat.
Your habitat might include your home, your school and the places where
you shop for things you req