Transcript Homework
Ecosystems Part 1 Levels of organization Levels of organization What is a species? Basic unit of biological classification Organisms that resemble each other, that are similar in genetic makeup, chemistry, and behavior, and that are able to interbreed and produce fertile offspring Is it a species? Vocab Intra = “within” Intraspecific interactions = ?? Inter = “Between” Interspecific interactions = ?? Population Dispersal patterns Clumped – most individuals are together Random – little interaction between members of a species In environments with patchy resources Most common in nature In environments with consistent resources Uniform – found when distance between neighbors is maximized Arises from competition for a resource Population dispersal patterns – the visual Ecological Niches Definition: ??? Influenced by the physical environment Take into account: Interactions with the biotic and abiotic environment Available resources To describe: Organisms adaptive traits Habitat Place in the food web Generalist vs. specialist Generalist: live in broad niches and withstand a wide range of environmental conditions Specialist: live in narrow niches and sensitive to environmental change (K-selected) (r-selected) Who has the advantage in the environment? Law of Tolerance The existence, abundance, and distribution of each species depends on the species tolerance to both the physical and chemical factors of the environment Limiting factor: any factor in the environment that limits the growth of a population Resource partitioning Species “share” a resource and avoid direct competition with each other Types: Temporal: use resource at different times Spatial: use the resource in different areas Morphological: evolves different characteristics to use the resource Ecosystem Community Characteristics 1. 2. 3. 4. Physical appearance: relative size, stratification, distribution of the populations and species Species diversity: number of different species Species abundance: number of individuals of each species Niche structure: number of ecological niches, how they resemble or differ from each other, species interactions Biological Interactions amongst species Interaction Description Example Amensalism One species suffers and the other is not affected -due to scarce resource -usually occurs with when one organism engages in chemical warfare Black walnut tree releases a chemical to kill neighboring plants Commensalism One species benefits and the other is not affected 1)Transportation 2)Housing 3)Use of something created 1) 2) 3) Shark and ramora Epiphytic plants Hermit crabs Biological Interactions amongst species Interaction Description Example Competition 1) Interference – directly between individuals 2) Exploitation – indirect by depleting a common resource 3) Apparent – indirectly when sought by same predator 1) Elk Mutualism Interaction where both species benefit Trees and mycorrhizal fungi and moose foraging 2) Grass and trees using water 3) Wolves hunting elk and moose Biological Interactions amongst species Interaction Description Example Parasitism One species benefits and the other is harmed -Tapeworm -cuckoo bird Predation Predator hunts and kills prey for food -?? Saprotrophism Obtain nutrients from -Fungi dead or decaying matter -vultures -dung beetles Key Stone Species A species whose presence contributes to the diversity of life and whose extinction would lead to extinction of other forms of life Dramatic shifts in the ecosystem can occur when a keystone species is removed Keystone species examples Sea Stars “Starfish” Sea stars prey on muscles, urchins, and other shell fish When removed muscle populations explode and out compete other organisms Sea urchins rise to the point they destroy coral reefs Sea Otter Prey on sea urchins Sea urchins eat through kelp holdfasts, which anchor the kelp to the ground, causing entire kelp forests to float away Wolves in Yellowstone Homework: Download the article from my website Read and annotate # paragraphs Highlight main ideas Write a one paragraph summary