B4.2 Ecological niches

What is an ecological niche?

A unique role a species plays in an ecosystem, including biotic and abiotic factors.

What determines the habitat of a species?

Zones of tolerance for abiotic variables.

What are the two methods of obtaining food in ecosystems?

Synthesis using light, water, and carbon dioxide, or by consuming other organisms.

Why must species specialize in their mode of nutrition?

To minimize competition.

What is the multidimensional aspect of an ecological niche?

It is made up of many factors that must all be satisfied for survival, growth, and reproduction.

What is the oxygen requirement for aerobic cell respiration?

Oxygen is required.

Where can anoxic conditions occur?

In swamps, water-logged soil, animal intestines, and deep lakes or seas.

What are the three categories of organisms based on oxygen requirements?

Aerobic, anaerobic, and facultative anaerobes.

Which two domains of life carry out photosynthesis?

Eukaryotes and bacteria.

What are the three groups of photosynthesizers?

Plants, eukaryotic algae, and photosynthetic bacteria.

How do animals obtain carbon compounds?

By consuming food; they are heterotrophic.

What is holozoic nutrition?

Nutrition involving ingestion, digestion, absorption, assimilation, and egestion.

How do spiders digest their food?

They inject digestive enzymes into their prey and suck out the liquids.

What is an autotroph?

An organism that makes its own carbon compounds from simple substances.

What is a heterotroph?

An organism that obtains carbon compounds from other organisms.

What is a mixotroph?

An organism that uses both autotrophic and heterotrophic nutrition.

What is a facultative mixotroph?

An organism that can switch between autotrophic, heterotrophic, or both modes of nutrition.

What are klepto-chloroplasts?

Chloroplasts obtained by consuming algae, used temporarily for photosynthesis.

What are saprotrophs?

Organisms that digest dead organic matter externally and absorb the products.

What role do decomposers play in ecosystems?

They recycle carbon compounds and release elements like nitrogen back into the ecosystem.

What are the three domains of life?

Archaea, bacteria, and eukaryotes.

What are phototrophic archaea?

Archaea that use light energy but not chlorophyll for ATP production.

What are chemotrophic archaea?

Archaea that oxidize inorganic chemicals for ATP production.

What is the main dietary feature of herbivorous Hominidae?

Large, flat molars for grinding fibrous plant tissue.

What type of dentition do omnivorous Hominidae have?

A mix of sharp canines, incisors, and flat molars for both plants and meat.

What adaptations help insects feed on plants?

Jaw-like mouthparts for chewing or tubular mouthparts for piercing and feeding on sap.

What are secondary metabolites in plants?

Toxic substances synthesized to deter herbivores.

What are some structural defenses in plants against herbivores?

Sharp spines, tough tissues, and stings.

What is the predator-prey adaptation relationship?

Predators develop adaptations to catch prey, while prey develop adaptations to resist predation.

What are behavioral adaptations?

Quickly evolving actions, such as blue tits feeding on milk bottle cream.

What are structural adaptations?

Physical changes like finch beak size evolving to fit seed size.

Why are chemical adaptations slower to evolve?

They often require new enzymes or regulatory mechanisms.

How do trees compete for light in forests?

By growing a dominant leading shoot to great heights.

What are lianas and how do they obtain light?

Climbing plants that use tree support to reach the canopy.

What are epiphytes and their adaptation for light?

Plants growing on tree trunks or branches to access higher light intensity.

What are strangler epiphytes?

Plants that encircle and outgrow trees, eventually killing them.

What is the fundamental niche of a species?

The full range of conditions it can tolerate without competition.

What is the realized niche of a species?

The actual range occupied due to competition.

What is competitive exclusion?

When one species outcompetes and excludes another from parts of its range.

What happens if two species' fundamental niches completely overlap?

One species will be competitively excluded from the ecosystem.

What is a unique ecological niche essential for?

The survival of a species in an ecosystem.

What is the role of light competition in forests?

It drives the diversity of plant forms and strategies.

What adaptations help predators catch prey?

Structural, chemical, or behavioral features.

What is the role of decomposers in nutrient cycles?

Breaking down dead organic matter to release nutrients for reuse.

How do facultative mixotrophs survive in changing conditions?

By switching between autotrophic and heterotrophic nutrition.

What are examples of facultative mixotrophs?

Euglena gracilis, which photosynthesizes or feeds on detritus.

What are obligate mixotrophs?

Organisms requiring both autotrophic and heterotrophic nutrition.

What adaptations allow beetles to feed on leaves?

Jaw-like mouthparts for biting and chewing.

What is the significance of photosynthesis?

It provides carbon compounds like sugars and amino acids for life.

What is the role of shade-tolerant plants in forests?

Absorbing limited light that reaches the forest floor.

What are the components of holozoic nutrition?

Ingestion, digestion, absorption, assimilation, and egestion.

What distinguishes archaea from other domains of life?

Adaptations to extreme environments and diverse ATP production methods.

What do herbivorous diets indicate about dentition?

Large molars for grinding plant tissue.

Why are adaptations important in ecological niches?

They enable species to survive and reduce competition.

What is assimilation in holozoic nutrition?

Synthesizing proteins and macromolecules from digested food.

What is the main role of saprotrophs?

Recycling organic matter by external digestion.

What is the primary function of epiphytes?

Accessing light without growing from the soil.

What does competitive exclusion demonstrate?

The importance of unique realized niches for species coexistence.

What factors define a species' ecological niche?

Biotic and abiotic elements essential for survival.