Learning Objectives By the end of this section, you will be able to: An ecosystem is a community of living organisms and their abiotic (non-living) environment. Ecosystems can be small, such as the tide pools found near the rocky shores of many…
Figure 20.1 The (a) Karner blue butterfly and (b) wild lupine live in oak-pine barren habitats in North America. (credit a: modification of work by John & Karen Hollingsworth, USFWS) Chapter Outline 20.1 Energy Flow through Ecosystems 20.2 Biogeochemical Cycles 20.3 Terrestrial Biomes 20.4 Aquatic and…
Population Demographics and Dynamics Populations are individuals of a species that live in a particular habitat. Ecologists measure characteristics of populations: size, density, and distribution pattern. Life tables are useful to calculate life expectancies of individual population members. Survivorship curves…
Learning Objectives By the end of this section, you will be able to: In general, populations of one species never live in isolation from populations of other species. The interacting populations occupying a given habitat form an ecological community. The…
Learning Objectives By the end of this section, you will be able to: Concepts of animal population dynamics can be applied to human population growth. Humans are not unique in their ability to alter their environment. For example, beaver dams…
Learning Objectives By the end of this section, you will be able to: Population ecologists make use of a variety of methods to model population dynamics. An accurate model should be able to describe the changes occurring in a population…
Learning Objectives By the end of this section, you will be able to: Populations are dynamic entities. Their size and composition fluctuate in response to numerous factors, including seasonal and yearly changes in the environment, natural disasters such as forest…
Figure 19.1 Asian carp jump out of the water in response to electrofishing. The Asian carp in the inset photograph were harvested from the Little Calumet River in Illinois in May, 2010, using rotenone, a toxin often used as an insecticide, in…
How Animals Reproduce Reproduction may be asexual when one individual produces genetically identical offspring, or sexual when the genetic material from two individuals is combined to produce genetically diverse offspring. Asexual reproduction in animals occurs through fission, budding, fragmentation, and…
Learning Objectives By the end of this section, you will be able to: As in all animals, the adaptations for reproduction in humans are complex. They involve specialized and different anatomies in the two sexes, a hormone regulation system, and…