Bio Chapter 17

evolution

change over time - most living things have genes that aren’t being used and evolution turns these genes on

Biogeography

discovery of new organisms in previously unknown places could not be explained by accepted beliefs

Examples of biogeography

ostrich, emu and rhea

What question does biogeography seek to answer?

How did these species get from center of creation to all these places?

Comparative morphology

study of similarities and differences in body plans of major groups

examples of comparative morphology

animals such as whales and bats have similar bones/forelimbs (some parts seem to have no function)

what do both humans and snakes share in common

pelvic girdle

George Cuvier

catastrophism - mass extinctions and survivors repopulated the world

Jean Lamark

inheritance of acquired characteristics forces drives to perfection up the chain of being

Darwins voyage

five year world voyage aboard the Beagle

Who was Darwin?

A naturalist who collected and examined species that inhabited the regions the ship visited

Galapagos Island

volcanic islands with finches with different types of beaks

blue footed boobie

different feet color → one baby kicked out of nest so mother can give best chance of life

Galapagos Finches

Darwin observed finches with a variety of lifestyles (13 species) → he attempted to correlate variations in their traits with environmental challenges

Lyell’s principles of geology

theory of uniformity - subtle repetitive processes of change had shaped earth challenged the view that earth was only 6,000 years

examples of theory of uniformity

earthquakes and tsunamis

reproductive capacity and competition

1. all populations have the capacity to increase in numbers

2. no population can increase indefinitely → eventually the individuals of a population will end up competing for resources

Variations in populations

all individuals have the same genes that specify the same assortment of traits but most genes occur in different forms (alleles) that produce different phenotypes and some phenotypes compete better than others

change over time

over time alleles that produce most successful phenotypes will increase population and less successful alleles will become less common

Darwins Theory

theory of natural selection (survival of the fittest)

a population can change over tine when individuals differ in one or more heritable traits that are responsible for differing in the ability to survive and reproduce

alfred wallace

naturalist who arrived at the same conclusion as Darwin did and wrote to him about it → prompted Darwin to finally present his ideas in a formal paper

Fossils

recognizable evidence of ancestral life

What do fossils tell us?

1. Each species is a mosaic of ancestral and novel traits

2. all species that ever evolved are related of one another by way of descent