Ecological Niche

Define niche

every species in an ecosystem fulfills a unique role

Niche is determined by…(4)

-habitat (where the organisms if found/lives)

-zone of tolerance

-how organisms obtain its food

-competition

Obligate aerobe

require a continuous oxygen supply so only live in oxic environments

Examples of obligate aerobes

Animals and plants; Micrococcus luteus (a skin bacterium)

Obligate anaerobe

inhibited or killed by oxygen so only live in anoxic environments

Examples of obligate anaerobe

Clostridium tetari (tetanus bacterium), methanogenic archaea

Facultative anaerobe

use oxygen if available;e so live in toxic or anoxic environments

Examples of facultative anaerobe

Escherichia coli (a gut bacterium), Saccharomyces (yeast)

Photosynthesis

energy from sunlight is used for fixing carbon dioxide and using carbon from it to produce sugars

List three groups or organisms that photosynthesize

plants, eukaryotic algae (some unicellular algae), and some bacteria (I.e. cyanobacteria)

What 2 domains are able to photosynthesize?

Eukaryotes and bacteria

What are the three modes of nutrition?

Holozoic, mixotrophic, and saprotrophic nutrition

Describe holozoic nutrition

whole pieces of food are swallowed before being digested

What are the five stages of holozoic nutrition?

Ingestion, digestion, absorption, assimilation, egestion

Ingestion

taking food into the gut

Digestion

breaking large food molecules into smaller molecules

Absorption

transportation of digested food across the plasma membrane of epidermis cell and thus into the blood or tissue

Assimilation

using digested foods to synthesize protein and other macromolecules and thus making them part of body’s tissues

Egestion

voiding undigested material from the end of the gut

Examples of organisms that use holozoic nutrition

humans and animals

Describe mixotrophic nutrition (the organisms that use it)

organisms use this who are not exclusively autotrophic or heterotrophic

Facultative mixotrophs can be…

entirely autotrophic, heterotrophic, or both modes

Obligate mixotrophs

must use both modes

What do some obligate mixotrophs do to use both modes?

some consume organisms to use their chloroplasts

Examples of organisms that use mixotrophic nutrition

Euglena gracilis (has chloroplasts for photosynthesis, but can also feed on detritus or smaller organisms by endocytosis)

Describe saprotrophic nutrition

organisms secrete enzyme into dead organic matter and digest it externally

What are some examples of organisms that use saprotrophic nutrition

bacteria and fungi

List the three modes of nutrition in the Domain Archaea

phototrophic, chemotrophic, heterotrophic

Phototrophic

absorption of light energy by pigments (other than chlorophyll)

Chemotrophic

oxidation of inorganic chemicals (i.e. Fe²⁺ ions to Fe³⁺)

Heterotrophic

oxidation of carbon compounds obtained from other organisms

List examples of family Hominidae

humans (Homo), orangutans (Pongo), gorillas (Gorilla), chimpanzees (Pan)

What type of animals have mostly molars?

Herbivores

What type of organisms have varied teeth types?

Omnivores, humans

List two organisms that have adaptations for feeding on plants

beetles and aphids

What is the adaptation of beetles (and similar organisms) for feeding on plants?

they have (and other insects) jawlike mouthparts for biting off, chewing, ingesting leaf parts

What is the adaptation of aphids (and similar organisms) for feeding on plants?

they have (and other insects) tubular mouthparts for piercing leaves/stems to reach phloem sieve tubes

Some do some herbivores do with plants that use toxins?

Some detox toxic compounds in plants

What are some adaptations that plants have to avoid being eaten?

tough sharp-pointed spines, stings, some synthesize toxic substances to herbivores in seeds

Describe a predator and how they have physically adapted to catch prey

Vampire bats (Desmodus rotundus) have unique dentition with small premolars and no molars, but large incisors and canines (pointed, razor sharp)

What do vampire bats use their physical adaptation for?

They use it to pierce prey to feed on the blood

Describe a predator and how they have chemically adapted to catch prey?

Black mambas (Dendroaspis polylepis) produce venom with neurotoxins (including an inhibitor of the enzyme acetylcholinesterase) paralyzes prey when injected via poison fangs

Describe an organism that has behaviorally adapted to catch prey?

Grizzly bear (Ursus arctos) learns ambush strategies for catching migration salmon by trial and error or copying others

Describe a prey that is physically adapted to resist predation

Buff-tip months (Phalera bucephala) have adapted to resemble broken birch twigs, giving them camouflage when roosting during daylight or during when they’re on the ground (times when they are most vulnerable for predation)

Describe a prey that is chemically adapted to resist predation

caterpillars of the cinnabar moth (Tyria jacobaeae) feed on ragwort and accumulate toxic alkaloids from it. They also yellow and black stripes to deter predators since it serves as a warning for retaining toxins

Describe a prey that is behaviorally adapted to resist predation

blue-striped snappers (Lutjanus kasmira) swim in a tight group with sudden changes of direction to reduce chance of predation

What is the result of environments where there is enough water for abundant plant growth and temperature are suitable for photosynthesis?

Increased competition for light

What do trees do during light competition?

They have dominant leading shoot that grows rapidly

What do lianas do during light competition?

climb through other trees for support

What do epiphytes do during light competition?

gain higher light intensity by growing on trunks and branches of trees

What do strangler epiphytes during light competition?

encircle tree trunks to shade leaves of trees

What type of plants must use light that reaches the forest floor?

Shade-tolerant shrubs and herbs

Fundamental niche

range of tolerance (tolerance to biotic and abiotic conditions) of a species

Realized niche

the actual extent of the potential range that a species occupies

Competitive exclusion principle

when the fundamental niches of two species overlap, one species is expected to exclude the other from the part of its range by competition