Evolution

Chapter 15

Two schools of thought Creation – God worshipping people Evolution – atheist

Creation vs. Evolution

Creation Evolution

Definition God created everything in the universe

Change of organisms over a long period of time

Time of Earth’s existence

More than 4,000 years

4.5 billion years

Life started with God made animals, plants, and people

A single cell organism

Creation vs. Evolution

Issue # 1: The origin of the earth Creation – God (or an intelligent designer) created

the heavens and earth Evolution – several ideas (have not decided on

one theory) Solar nebular theory – Hydrogen and helium came

together to form stars. When stars die, they explode releasing clouds of gas and dust. The dust started to stick together. Over millions of years, they formed planets.

Creation vs. Evolution

Creation vs. Evolution

Issue # 2: People believed the earth was flat Columbus “proved” that the earth is round in the

15th century

Isaiah 40: 21-22 states that the earth has a circular shape

Evolution

Evolution – a change in an organism over a long period of time

Charles Darwin – the father of evolution Darwin had some proof to support his theory

The shape of fossils Darwin’s time on the HMS Beagle Darwin’s trip to the Galapagos Islands

Located off of South America Galapagos tortoises and Galapagos finches

Evolution

Galapagos tortoises

Evolution

Galapagos finches

Artificial Selection

Artificial selection – breeding organisms with specific traits in order to produce offspring with identical traits Man chooses which traits

organisms should have Example – dogs and

cows

Artificial Selection

Example – beef cows vs. dairy cows

Natural Selection

Natural selection – occurs when organisms with favorable variations survive, reproduce, and pass their variations to the next generation Selection occurs on its

own or “naturally” Example – birds with

long tail feathers

Natural Selection

Darwin called natural selection “survival of the fittest” Stronger organisms with

preferred traits lived and made fertile offspring

Example – Two populations of fish One population is faster

than the other

Natural selection would favor which population?

“X” indicates faster swimmer

Natural Selection

Natural selection would favor polar bears in the arctic and grizzly bears in the taiga. Why?

Adaptations: Evidence for Evolution Adaptation – any

variation that aids an organism’s chances of survival in its environment

Adaptations in species develop over many generations

Adaptations of a frog

Adaptations: Evidence for Evolution Several forms of

adaptations: Mimicry – a structural

adaptation that enables one species to resemble another species

Adaptations: Evidence for Evolution

Aggressive mimicry – a technique used by some animals to lure prey to them by mimicking something else Angler fish

Adaptations: Evidence for Evolution

Aggressive mimicry Golden orb weaver will

weave heavy zig-zag lines of web to attract insects Found in Australia

Adaptations: Evidence for Evolution

Aggressive mimicry Snapping turtle’s tongue

resembles a worm

Adaptations: Evidence for Evolution

Camouflage – an adaptation that enables species to blend with their surroundings

Adaptations: Evidence for Evolution

Warning coloration – A protection adaptation used by some animals that uses color to warn other animals to keep away Yellow jacket Poison dart frog

Other Evidence for Evolution

Anatomy Homologous structures – structures with common

evolutionary origins Provides evidence of evolution from a common ancestor Examples: forelimbs of lizards, whales, humans, and

birds

Other Evidence for Evolution

Analogous structures – structures that do not have a common evolutionary origin but are similar in function

Other Evidence for EvolutionInsect

PterodactylBat

Bird

Analogous structures

Other Evidence for Evolution

Vestigial structure – a structure in a present-day organism that no longer serves its natural purpose, but was probably useful to an ancestor Example: appendix

Other Evidence for Evolution

Embryology – the earliest stage of growth and development of both plants and animals

Population Genetics and Evolution Evolution occurs on populations, not

individuals Variation coupled with natural selection fuels

evolution Gene pool – all of the alleles in a population’s

genes

Population Genetics and Evolution Natural selection acts on variations

Stabilizing selection –favors average individuals in a population

Directional selection – favors one of the extreme variations of a trait

Disruptive selection – individuals with either extreme of a trait’s variation are selected for Tends to eliminate intermediate phenotypes

The Evolution of Species

Speciation – the evolution of a new species Several ways for speciation to occur:

Geographical isolation – a physical barrier divides a population

The Evolution of Species

Reproduction isolation – formerly interbreeding organisms can no longer mate and produce fertile offspring

Patterns of Evolution

Adaptive radiation (divergent evolution) – an ancestral species evolves into an array of species to fit a number of diverse habitats

Laysan finches from the Hawaiian islands

Patterns of Evolution

Convergent evolution – occurs when unrelated species evolve similar traits