3 - 1 © 2000 pearson education canada inc.,toronto, ontario evolution, heredity, and behaviour...

Evolution, Heredity, and Behaviour 3 - 1 © 2000 Pearson Education Canada Inc.,Toronto, Ontario

Lecture # 3 GENETICS and EVOLUTION


Evolution, Heredity, and Behaviour

The Development of Evolutionary Theory Charles Darwin and origin of species

a species’ behaviour (and physical make-up) is due to the constant (natural occurring) reproductive pressure to propagate the species ie giraffes, sickle cell anemia, bacterial antibiotic resistance


A Couple of (important) definitions:

Genotype: the collection of genes which define the biological potential of an organism

Phenotype: the actual behavioural or physical state that results from gene expression and other outside influences


Biological evolution: alterations in the the phenotype of an organism due to changes in the genetic make-up (genotype).

HOW DOES THIS WORK?


Natural Selection and Evolution

Artificial Selection – A procedure in which animals are deliberately mated to produce offspring that possess particularly desirable characteristics.

Natural Selection – The consequence of the fact that organisms reproduce differentially, which is caused by behavioural differences among them. Within any given population, some animals – the survivors – will produce more offspring than will other animals.


The Development of Evolutionary Theory

Varieties of pigeons believed to have been produced through artificial selection:

(1) Wild rock pigeon (ancestor)(b) Blue grizzle frillback(c) English pouter(d) Indian Fantail

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SO…why aren’t there wolves who can run as

fast as a cheetah?

There are a number of factors…•Genetic potential

• i.e. biomechanics•Confounding disadvantages

•inability to change direction quickly reduces hunting success


Reproductive success – the number of viable offspring an individual produces relative to the number of viable offspring produced by other members of the same species

Variation – the differences found across individuals of any given species in terms of their genetic, biological, and psychological characteristics



Environment can play an important role. Consider the role of intereuterine sex hormones

Adaptive modification: alteration in behaviour due to an outside source of variabilty.

Are the genes you are “dealt” the only factor in

your reproductive success ?

NO!


Heredity and Genetics

The structure and composition of DNA. Genes serve as “recipes” for the synthesis of proteins and enzymes.

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The Flow of Genetic Information

DNA

Protein

translation

FUNCTION

transcription

UCGA

RNA

Enviromental factors



The determination of sex. The sex of human offspring depends on whether the sperm that fertilizes the ovum caries an X or a Y chromosome.

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Sociobiology Sociobiology – the study of the genetic bases

of social behaviour

Parental Investment – the resources that a parent spends in procreations and feeding, nurturing, and protecting of offspring

Sexual Selection – selection of traits specific to sex, such as body size or particular patterns of behaviour

Reproductive Strategies – different systems of mating and rearing offspring, including monogamy, polygyny, polyandry, and polygynandry


Sociobiology

Monogamy – the mating of one female and one male

Polygyny – the mating of one male with more than one female

Polyandry – the mating of one female with more than one male

Polygynandry – the mating of several females with several males


Reproductive Strategies

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3 - 1 © 2000 pearson education canada inc.,toronto, ontario evolution, heredity, and behaviour...

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