lecture 2

10 inference 3 the unequal ability of individuals to

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: r reading Malthus. •  Observation #4: Members of a population vary extensively in their characteristics –  No two individuals are exactly alike Figure 22.9 15 9/30/12 •  Observation #5: Much of this variation is heritable –  Experiments in plant and animal breeding prove this. •  Inference #2: Survival may depend in part on inherited traits Terminal Lateral buds bud Brussels sprouts Cabbage Flower cluster Leaves Cauliflower Kale Flower and stems Broccoli –  Individuals whose inherited traits give them a high probability of surviving and reproducing are likely to leave more offspring than other individuals Stem Wild mustard Kohlrabi Figure 22.10 •  Inference #3: The unequal ability of individuals to survive and reproduce –  Will lead to a gradual change in a population, with favorable characteristics accumulating over generations •  This is the process called Natural Selection –  All that is required for this process is heritable (that is, genetic) variation that affects fitness Summary of Natural Selection •  Natural selection is differential success in reproduction –  That results from the interaction between individuals that vary in heritable traits and their environment 16 9/30/12 •  Natural selection can produce adaptations of organisms to their environment (a) A flower man8d in Malaysia (b) A s8ck man8d in Africa Figure 22.11 •  If an environment changes over time –  Natural selection may result in adaptation to these new conditions Natural Selection in Action •  Two examples –  Darwin s Finches –  HIV 17 9/30/12 A case study: Natural Selection Darwin s Medium Ground Finch •  Seed eater living on Daphne Major Island •  Drought in 1977 caused 84% mortality •  Only large hard seeds remained for food Evolution by Natural Selection •  Requires heritable variation that affects fitness •  Predicts:...
View Full Document

This note was uploaded on 02/06/2014 for the course BILD 3 taught by Professor Wills during the Fall '07 term at UCSD.

Ask a homework question - tutors are online