Lecture 24a Flashcards
What is Emergent Complexity (or Emergence)?
A process whereby larger entities, patterns, and regularities arise through interactions among smaller or simpler entities that themselves do not exhibit such properties.
Why did the emergent complexity of snowflakes occur?
Because it is thermodynamically favored over disorder.
In terms of Emergent Complexity, how can life on Earth be thought of as?
The life currently on Earth can be thought of as emergent complexity that has developed over 4.3 billion years.
Emergent Complexity is continuing, both at the ______________ level and on _____________ levels. For example, humans are getting increasingly integrated/organized.
organismal, broader
Who was the first to theorize that existing species evolved from pre-existing ones?
Charles Darwin
What were the 3 important influences that helped Darwin develop his theory?
1) Theories of Geology
2) Darwin’s own experimental observations
3) Thomas Malthus’ “Essay on the Principle of Population”
How did Theories of Geology influence Darwin’s theory?
The Earth is very old and slow geological processes change the Earth’s characteristics.
How did Darwin’s own experimental observations influence his theory?
He made a voyage aboard the HMS Beagle where he carefully examined many different species. He noted similarities, but also differences that enabled various species to adapt to different environmental conditions.
How did Thomas Malthus’ “Essay on the Principle of Population” influence Darwin’s theory?
In this essay published in 1798, Malthus asserted that resources cannot keep up with the reproductive potential of humans. He argued that famine, war, and disease will limit population growth, especially among the poor.
When had Darwin largely formulated his theory of evolution by? When did he begin to write his book?
By the mid-1840s.
In 1856, he began to write a long book to explain his ideas.
Who was Alfred Wallace and what did he do?
A naturalist working in the East Indies who independently proposed the same ideas as Darwin concerning evolution.
In 1858, two papers, one by ____________ and one by _____________, were published in the Proceedings of the Linnaean Society of London.
Darwin, Wallace
In 1859, what did Darwin publish and what did it talk about?
His book “On the Origin of Species by Means of Natural Selection”
In it, Darwin expounded his ideas in greater detail and with experimental support.
Evolution needs __________ ____________, which is a consistent feature of most natural populations.
Genetic Variation
What did Darwin assume in regard to Genetic Variation? What did he not know?
Darwin assumed that some phenotypic variation is passed from parent to offspring.
However, he did not know the genetic basis for inheritance of traits.
Genetic Variation can involve what 3 things?
1) Allelic differences in genes
2) Changes in chromosome structure
3) Alterations in chromosome number
What is a Species?
A group of individuals whose members can interbreed to produce viable, fertile offspring.
The members of one species cannot successfully interbreed with members of other species.
T/F: Cheetah and lion are the same species.
False! While a cheetah and lion can mate, the offspring they produce would be sterile, thus, they are not part of the same species.
A single species may exist in….?
A single species may exist in 2 or more distinct populations that are evolving slowly into different species.
What is an Ecological Niche?
Describes how an organism or population responds to the available resources, competitors, and challenges (predators, pathogens, etc.), and how it in turn alters those same factors.
How an organism or population responds to and interacts with its environment.
T/F: A species tends to occupy more than a few ecological niches.
False! A species tends to occupy one or a few ecological niches.
Species are ________________ isolated from other species. Thus, they cannot successfully interbreed with other species.
reproductively
The reproductive isolation of a species can be achieved by what 2 mechanisms?
Prezygotic and Postzygotic mechanisms.
What are Prezygotic mechanisms?
Something prevents the formation of a zygote (fertilized egg).
What are Postzygotic mechanisms?
Something prevents the development of a viable or fertile offspring after fertilization has taken place.
