A4.2 Ecological Niches

Question 1

What are some of the biotic and abiotic elements for ecological niches?

Answer 1

• Zones of tolerance for abiotic variables determine the habitat of a species.
• Food supply is a (biotic element) that can be autotrophic or heterotrophic. Species become specialist in sourcing food by making adaptations to minimize food competition.
• (biotic) Utilization of other species to provide a diverse range of services, pollination of flowers or nesting sites in tree holes.

Question 2

Where do conditions for anoxic habitats occur?

Answer 2

Swamps, Water-logged soil, deep lakes or seas.

Question 3

Obligate aerobe (definition and example):

Answer 3

Oxygen must be available for aerobic respiration.
Ex: All plants and animals, (Micrococcus Luteus).

Question 4

Obligate anaerobe definition + example

Answer 4

Conditions must be anoxic as oxygen kills the organism.
Ex: Tetanus Bacterium, Methanogenic archae.

Question 5

Facultative Anaerobe definition + example:.

Answer 5

• Oxygen is used if available but anoxic conditions are tolerated, Escherichia Coli, Saccharomyces

Question 6

What groups of organisms use photosynthesis?

Answer 6

• Plants - Mosses, ferns, conifers, and flowering plants.
• Eukaryotic algae - including rocky shore seaweeds and unicellular algae such as chlorella.
• Cyanobacteria (blue-green bacteria) and several bacteria groups.

Question 7

In how many domains does photosynthesis occur in?

Answer 7

2, Eukaryotes and Bacteria. (Not archea)

Question 8

Heterotrophic organisms…

Answer 8

Organisms that get their carbon compounds from other organisms.

Question 9

Basic definition of Holozoic Nutrition

Answer 9

The internal digestion of food after it has been ingested in pieces.

Question 10

What are the 5 stages of holozoic nutrition?

Answer 10

1) Ingestion— Taking food into the gut
2) Digestion— breaking down large food molecules into smaller ones.
3) Absorption— Transport of digested food across epidermis cells to tissues and blood in the body.
4) assimilation— Using Digested foods to synthesize proteins and other macromolecules.
5) Egestion — Voiding Undigested materials from the end of the gut.

Question 11

Some animals digest their food externally, would you classify them as holozoic? give an example of these animals.

Answer 11

They are not holozoic, spiders (for ex) inject their prey with enzymes and suck out the liquids produced, then absorb the products of digestion in their gut then assimilate them.

Question 12

Mixotrophic

Answer 12

• Not exclusively autotrophic or heterotrophic, for example unicellular eukaryotes that can obtain carbon compounds from other organisms or create them themselvesl

Question 13

Mixotrophic

Answer 13

• Not exclusively autotrophic or heterotrophic, for example unicellular eukaryotes that can obtain carbon compounds from other organisms or create them themselves.

Question 14

Facultative Mixotrophs

Answer 14

• Can be entirely autotrophic, entirely heterotrophic, or use both.
• Euglena gracilis, has chloroplasts + carries out photosynthesis but can feed on detritus/ tiny ppl by Endocytosis.

Question 15

Obligate Mixotrophs

Answer 15

• Must utilize both autotrophic and heterotrophic modes of nutrition, because food that they consume supplies them with carbon compounds they cannot synthesize themselves.
• Protists may consume algae to obtain chloroplasts they use for photosynthesis.

Question 16

Features of Archaea

Answer 16

• Unicellular, no nucleus.
• Closer to eukaryotes
• Some adapted to extreme environments (Hot springs, salt lakes, soda lakes)
• Extremely diverse in sources of ATP

Question 17

Chemoheterotrophs

Answer 17

Produce energy through the oxidation of carbon compounds obtained from other organisms, obtain carbon compound from other organisms.

Question 18

Photo heterotrophs

Answer 18

Produce energy through the absorption of light pigments (not chlorophyll), obtain carbon compounds from other organisms.

Question 19

Chemoautotrophs

Answer 19

Produce energy from the oxidation of inorganic chemicals (fe2+ —> fe3+), synthesize carbon compounds from carbon dioxide by anabolic reactions.

Question 20

Saphotrophs

Answer 20

Feed on dead organic matter by secreating proteases to digest proteins into amino acids and other enzymes, the small, soluble products of digestion diffuse inside the cells where they are absorbed and used.

Question 21

Form and Function in dentition of herbivores (plant eaterss):

Answer 21

• Large and Flat to grind down fibrous plant tissues

Question 22

Omnivore dentition

Answer 22

• Mix of different types of teeth to break down both meats and plants in their diets.
• Humans have flat molars to grind food and sharper canines and incisors than herbivores to tear tougher foods and meat.

Question 23

Insects that feed on leaves (beetles for example) adaptations:

Answer 23

• Jaw-like mouthparts, tough mandibles for biting off and chewing leaves.

Question 24

Insects that feed on phloem sieve tubes (aphids for example) adaptations:

Answer 24

• Sharp, Tubular mouth parts for piercing leaves or stems to reach the tubes.

Question 25

Insects that feed on nectar (butterflies for example) adaptations:

Answer 25

• Tubular mouthparts long enough to reach the nevtary on the right in flowers.

Question 26

Adaptations of plants for deterring herbivore attacks:

Answer 26

• Sharp spines (thorns on a rose)
• Strings to cause pain (Stinging nettle)
• Synthesis and storage of secondary metabolites that are toxic to herbivores.
• Toxic substances placed in seeds which are attractive to herbivores due to their protein and starch or oil.

Question 27

Structural adaptations in predators and prey:

Answer 27

• Pointed upper teeth in vampire bats for piercing prey to suck out blood. (Predator)
• Shells of limpets on rocky shores to protect soft parts of the mollusc’s body.

Question 28

Chemical Adaptations in predators and prey:

Answer 28

• Venom produced by black mambas to paralyze and kill prey. (Predators)
• Toxins accumulated from ragwort plants eat in cinnabar moth larvae. (Prey)

Question 29

Behavioral adaptations in predators and prey:

Answer 29

• Luring prey by luminescent fin ray in anglerfish (predator)
• Swimming in tight groups in blue-striped snappers and other fish.

Question 30

Plant adaptations for harvesting light:

Answer 30

• Dominant leading shoot —> rapid growth in height so light isn’t caste by other trees.
• Lianas climb other trees for support —> less xylem tissue than free-standing trees.
• Epiphytes grow on trunks and branches —> receive more light than when in soil.
• Strangler epiphytes outgrow tree branches —> shade out their leaves.
• shade-tolerant shrubs and herbs absorb the small amounts of light that reach the forest floor.