Biology- Ecological niches

B4.2

obligate aerobes (def+ex)

require continuous supply of O2 only live in oxic environments. all animals plants

obligate anaerobes

inhibited/killed by oxygen. only live in anoxic environments. tetanus bacteria, methanogenic archaea

facultative anaerobes

use oxygen if available, can live in both oxic and anoxic environments. E. coli, yeast

what domains does photosynthesis happen in

eukaryotes and bacteria, NOT archaea

holozoic nutrition and steps

food is swallowed before being digested

steps:

ingestion- taking food into gut

digestion- breaking large food molecules into smaller molecules

absorption- transport across plasma membrane of epidermis into blood and tissues

assimilation- using digested foods to synthesize proteins and other macromolecules, making them a part of the body’s tissue

egestion- voiding undigested material from end of the gut

mixotrophic nutrition

organisms not only auto or heterotrophic but both like some protists

facultative mixotrophs- can be entirely one or use both. eg. euglena gracilis photosynthesises but also eats detritus or smaller organisms

obligate mixotrophs have to use both

saprotrophic nutrition

secrete digestive enzymes into dead organic matter and digest externally

diversity of nutrition in archaea

phototrophic- absorption of light energy by pigments (not chlorophyll)

chemotrophic- oxidation of inorganic chemicals

heterotrophic- oxidation of carbon compounds from other organisms

dentition and diet

herbivores- large flat teeth grind down fibrous plants

omnivores- mix of teeth. humans- flat molars but sharp canines and incisors

how does secondary metabolism help plants

they can synthesise toxins and chemicals to deter herbivores and store them in seeds or other parts. but sometimes herbivores develop detoxification abilities.

range of tolerance+niche

ROT is the fundamental niche of a species

realized niche

formed by competition exclusion principle. smaller part of fundamental niche. every species must have a realized niche different from all other species to survive in an ecosystem.