Ecosystems

Producers Producers – autotrophs Make their own food Photosyntheis chemosynthesis

Consumers Heterotrophs obtain their food by feeding on other organisms Herbivores – eat plants Carnivores – eat meat Omnivores – eat plants and animals

Decomposers Consumers that release nutrients in the process of obtaining nutrients Detritivores – feed on wastes or decaying bodies of other organisms

Food chain/food web Sequence of organisms each acting as a nutrient for the next organism Complex network of interconnected food chains

Ecology How organisms interact with one another Five levels: Organisms – an individual being Populations-a group of individuals of the same species Communities-populations of different species living in a particular area Ecosystems-a community interacting with one another and their nonliving environment Biosphere-parts of earth where life is found

Evolution Process whereby earth’s life changes over time through changes in the genetic characteristics of populations Begins with a mutation (change in DNA) that results in a new genetic trait Natural selection-environmental conditions favor some individuals with certain traits that give them an advantage enabling them to survive and reproduce at a higher rate

Spreads northward and southward and separates Early fox population Adapted to cold through heavier fur, short ears, short legs, and short nose. White fur matches snow for camouflage. Arctic Fox Northern population Different environmental conditions lead to different selective pressures and evolution into two different species. Spreads northward and southward and separates Early fox population Gray Fox Figure 4.10: Geographic isolation can lead to reproductive isolation, divergence of gene pools, and speciation. Southern population Adapted to heat through lightweight fur and long ears, legs, and nose, which give off more heat. Fig. 4-10, p. 91

Niche A species’ way of life in a community and includes everything that affects its survival and reproduction How much water and sunlight it needs how much space it requires What it feeds on and what feeds on it

Figure 4.14: This diagram illustrates the specialized feeding niches of various bird species in a coastal wetland. This specialization reduces competition and allows sharing of limited resources. Fig. 4-14, p. 96

Species Interact in Five Major Ways Interspecific Competition-species compete for resources Predation-predator feeds on all or part of the prey as part of a food web Parasitism-one species feeds on or inside the host; host is often harmed Mutualism-two species behave in such a way that both benefit Commensalism

Interspecific Competition Competition for limited resources One species becomes more efficient than another species When 2 species compete their niches overlap Greater overlap – more intense competition

One species takes the larger share of resources Competing species must: Move to another area Adapt by shifting feeding habits/behavior through natural selection to alter its niche Suffer population decline Become extinct

The variety of species and the genetic variety within a species What is biodiversity? The variety of species and the genetic variety within a species

Abiotic factors – the nonliving parts of an ecosystem sunlight water Rocks and soil

Biotic factors - the living parts of an ecosystem Plants, animals and microorganisms

Identify biotic and abiotic factors in each picture.

biome Large regions with distinctive climates and organisms (especially vegetation) adapted to them

Biomes of the 39th parallel of the US

Threats to biodiversity H – habitat destruction I – invasive species P – population growth P – pollution C – climate change O - overexploitation

Native versus nonnative A native species is a species that normally lives in and thrives in an ecosystem. A nonnative species is a species that migrates into or is introduced into an ecosystem (also referred to as exotic species) Invasive species are species that are nonnative and harmful to their new ecosystem (invasive because they have no natural predators or competition to control their numbers)

Invasive species Kudzu – brought from Japan to control erosion Zebra mussels – clog water lines – brought in accidentally on ships Fire ants nutria