Transcript Chapter 16 - Biology

Chapter 16
DARWIN
Evolution Game
 Play the game “Who wants to live a million years” on
Miss D’s wikispace
 If you finish before time is called, click around on the
other links (Quiz, Natural Selection, or Darwin’s Bio)
With your partner…
 Was the game easy or hard? Explain.
 Was there a trick to the game? Explain.
 What mechanism of evolution is this game
explaining?
 What types of forces cause evolution to occur?
Darwin’s Theory of Evolution
 Darwin is the father of
evolution
 Evolution = the process of
change over time, descent
from common ancestors
 Evidence:
1. Species vary globally
2. Species vary locally
3. Species vary over time
Why study tropical areas?
Species vary Globally
 Rheas = flightless birds that look and act a lot like
ostriches, yet rheas lived in South America
 Ostriches lived in Africa
 Emu lived in Australia
 Darwin noticed that different, yet
ecologically similar, animal species
inhabited separate, but ecologically similar,
habitats around the globe.
Species vary
locally
 Two species of Rhea’s living in South America
 Species = population that can breed and produce
fertile offspring
 Different shell shapes in tortoises of Galapagos
 Darwin noticed that different, yet related,
animal species often occupied different
habitats within a local area
Species vary over time
 Darwin collected fossils (preserved remains of
animals)
 Some fossils of extinct animals were similar
to living species.
Ideas that Shaped Darwin’s Thinking
 Hutton and Lydell proved that Earth is extremely old
and that the processes that changed Earth in the past
are the same processes that operate in the present.
 Examples?
 Darwin - If Earth changed over time, could life too?
Lamarck’s Evolutionary Hypthesis
 Read p. 456 with a partner and explain why
Lamarck’s ideas were not correct
Malthus’s view
 If human population grew unchecked, there would
not be enough living space and food for everyone.
Artificial Selection
 Artificial selection: the selective breeding of
domesticated plants and animals
 Shows convincing evidence that humans were
playing the role of the environment in nature
Natural Selection
 Natural selection the basic
mechanism of evolution
1. Struggle for existence
2. Variation and adaptation
3. Survival of the fittest
(fitness = survival and
reproduction)
Struggle for Existence
 Members of a population must compete for food,
living space, etc.
Variation and Adaptation
 Some variants are better suited than others
 Faster, longer claws, camouflage, sharper teeth
 Adaptation = heritable characteristic that increases
organisms ability to survive and reproduce
 Bowerbird display
Survival of the Fittest
 Differences in adaptation affect fitness (how well an
organism can survive and reproduce
 Different in rates of survival and reproduction=
survival of the fittest
Natural selection
 Process by which organisms with variations most
suited to their local environment survive and leave
offspring
 Similar to artificial, but nature is controlling
 When does it occur?



More individual are born than can survive (struggle for
existence)
Natural heritable change (variation and adaptation)
Variable fitness among individuals (survival of the fittest)
Natural Selection Myths
 Does not make organisms better
 But does enable them to pass on their genes
 Does not move in a fixed direction
 No one perfect way of doing something, ex pollination
 Not the only mechanism that drives evolution
Common descent
 According to the
principal of common
descent, all species –
living and extinct –
are descended from
ancient common
ancestors
 Evidence?
Evidence of Evolution
Biogeography (distribution)
2. The Age of Earth and Fossils
3. Comparing Anatomy and Embryology
(homologous, analogous and vestigial structures)
4. Genetics and Molecular Biology (amino acid
sequences)
1.
Lab – Evidence of Evolution