Ecological Niche The ecological niche of an organism Is a complex set of interactions between an organism and its surroundings For example, a beaver's ecological niche includes building dams and flooding forested areas, killing trees providing habitat for the ducks and other animals, serving as food for predators
Ecological Niche The ecological niche of an organism is a complex set of interactions between an organism and its surroundings. For example, a beaver’s ecological niche includes building dams and flooding forested areas, killing trees, providing habitat for the ducks and other animals, serving as food for predators
The Niche of a dandelion a dandelion serves as food to various herbivores, supplies nectar to bees, and can regrow quickly from its root if its leaves are removed
The Niche of a Dandelion A dandelion serves as food to various herbivores, supplies nectar to bees, and can regrow quickly from its root if its leaves are removed
Role of natural selection and evolution Genes, Populations, and Species: Three interrelated concepts Genes: Genes are distinct pieces of DNA (deoxyribonucleic acid) that determine the characteristics an individual displays Population: a population is considered to be all the organisms of the same kind found within a specific geographic region Species: A species is a population of all the organisms potentially capable of reproducing naturally among themselves and having offspring that also reproduce An individual organism is not a species but a member of a species
• Genes, Populations, and Species: Three interrelated concepts – – Genes: Genes are distinct pieces of DNA (deoxyribonucleic acid) that determine the characteristics an individual displays. – Population: A population is considered to be all the organisms of the same kind found within a specific geographic region. – Species: A species is a population of all the organisms potentially capable of reproducing naturally among themselves and having offspring that also reproduce. An individual organism is not a species but a member of a species. Role of Natural Selection and Evolution
Natural selection Natural Selection: Process that determines which individuals within a species will reproduce and pass their genes to the next generation Evolution: The changes in the genes and the characteristics displayed by successive generations of a population of organisms over time Natural selection is the mechanism that causes evolution to occur Conditions Involved in the process of natural Selection: Individuals within a species show variation Organisms within a species typically produce huge numbers of offspring most of which die
Natural Selection • Natural Selection: Process that determines which individuals within a species will reproduce and pass their genes to the next generation. • Evolution: The changes in the genes and the characteristics displayed by successive generations of a population of organisms over time. – Natural selection is the mechanism that causes evolution to occur. • Conditions Involved in the Process of Natural Selection: – Individuals within a species show variation. – Organisms within a species typically produce huge numbers of offspring, most of which die
Natural selection Conditions Involved in the process of natural Selection Excess number of individuals results in a shortage of specific resources Due to individual variation some individuals have a greater chance of obtaining needed resources and thus have a greater likelihood of survival and reproduction As time passes, percentage of individuals showing favorable variations will increase and percentage showing unfavorable variations will decrease
Natural Selection • Conditions Involved in the Process of Natural Selection: – Excess number of individuals results in a shortage of specific resources. – Due to individual variation, some individuals have a greater chance of obtaining needed resources and thus have a greater likelihood of survival and reproduction. – As time passes, percentage of individuals showing favorable variations will increase and percentage showing unfavorable variations will decrease