{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Ch 13 how populations evolve

Ch 13 how populations evolve - Chapter 13 How Populations...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 13- How Populations Evolve Biologist’s definition Evolution=the processes of change in the forms of life over earth’s history Never in the life of one individual Never by self-will Limited by inherent genetic variation 1) Charles Darwin and his theory a) Historical Context i) Concept of “fixed” or “ideal” species prevailed until 1700’s (1) Aristotle ii) Buffon (mid-1700s): old earth, changed life forms iii) Erasmus Darwin (late 1700’s, grandpa to Charles): proposed life “improved” over millions of ages from simple, minute forms iv) Lamarck (1809): present-day forms evolved from older forms (1) But wrong about how “acquired characteristics” v) Lyell (1830): Principles of Geology (1) Evidence that earth is extremely old (2) Major features in earth caused by small changes over vast time: gradualism b) What Darwin did i) Naturalist on HMS Beagle 1831-1836[13.4] (1) Visited South America, Galapagos Island, Australia (2) Studied and collected life, rocks, and fossils ii) Studied and Wrote in England for 23 years iii) Origin of Species in 1859 c) Darwin’s Observations i) Great geographic diversity of life ii) Distinct island species resembled nearby continental species, yet “adapted”
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
(1) Ex- iguanas [13.5] (2) Galapagos finches [13.5] iii) Rock formations suggested very old earth (1) As Lyell wrote (2) Yet fossils in local areas resembled living species iv) For all life, reproduction far exceeds resources (1) Inspired by Malthus’ ideas about human populations: the poor and weak suffer the most v) Tremendous amounts of variation possible thru artificial selection [1.15] (1) Ex- cabbage, broccoli, cauliflower all on species (2) Ex- pigeons d) Darwin’s Theory i) Part 1: Descent with modification (evolution) = all life is related thru descent from a common ancestor in past (like a branching tree) ii) Part 2: Natural Selection (mechanism for evolution) (1) Observation #1- overproduction: (a) All organisms produce more offspring than needed to replace them (b) Most populations remain stable in size (c) Resources for life are limited (2)
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 7

Ch 13 how populations evolve - Chapter 13 How Populations...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon bookmark
Ask a homework question - tutors are online