Biology Recall

biomass

is the total mass of biological matter (living or dead) in a given area, at the time of measurement, that can be used as an energy source.

what provides the energy for all ecosystems

ultimately all energy starts at the sun (solar energy) and energy and matter interact in the ecosystem

what are the organisms called which are at the start of all food chains?

Light enters an ecosystem through producers (plants/algae), via photosynthesis and are called autotrophs (auto = self, troph = feeding)

what is most of the energy harnessed by the sun in plants used for

power cellular respiration, which sustains their metabolic processes, growth, and maintenance

what do animals use the energy from respiration for

to power essential life processes, maintain homeostasis, and perform physical activities

give an example of units for measuring biomass?

•mass: g m^–2 year ^{– 1}

•energy: kJ m ^{– 2} year ^{– 1}.

what is a benefit of using pyramids of energy over biomass?

they always display an upright, accurate representation of energy flow across time, showing the precise rate of productivity and energy loss

What is GPP

Gross Primary Productivity (GPP) is the total rate at which photosynthetic organisms (producers) capture the total solar energy and convert it into chemical energy (organic matter/biomass) in an ecosystem

what don't plants take in all of the available energy

Plants don't absorb all available sunlight because they primarily use specific wavelengths (blue and red) for photosynthesis, reflecting green light

What is NPP

Net primary productivity is the difference between the total energy that is fixed by the autotrophs and the energy expensed as their own respiration losses

state the question that links NPP/GPP/R

NPP = GPP - R

why isn’t the transfer of energy from producers to primary consumers very efficient

The transfer of energy from producers to primary consumers is inefficient, typically following the "10% rule," because most energy is lost as heat during respiration, excreted as waste, or remains uneaten

what is a keystone specie? give an example

a keystone species is a species with a dramatically large effect on an ecosystem relative to its abundance e.g. migrating birds depend on carcasses

compare the three species concepts

morphological species - classifies species based on distinct physical, anatomical, or structural features

phylogenetic species - defines a species as the smallest, or most basal cluster of organisms that share a common ancestor and can be distinguished from other sets

biological species concept - defines species as a group of interbreeding natural populations that are reproductively isolated from other such groups

Differentiate between fundamental niche and realised niche

fundamental niche - the entire set of conditions under which an organism can survive and reproduce e.g. where it can live without competition

realised niche - the set of conditions actually used by a given organism after interactions with other species are taken into account e.g. where it does live due to competition

what are the three main groups of mammals

monotremes (egg-laying), marsupials (pouch bearing), and placentals (developed in the uterus)

what are the three levels of biodiversity

species diversity - is the variety of different species within an area

ecosystem diversity - the variety of habitats that support different communities

genetic diversity - is the variation in DNA within a population or species

write down the species name for humans, using correct formatting

Homo sapiens

compare archaea, bacteria, fungi, protists, plants and animals

• Archaea and Bacteria are single-celled, nucleus-free prokaryotes, with Archaea often living in extreme environments and differing in cell wall composition.

• Fungi, Protists, Plants, and Animals are eukaryotes (containing a nucleus and organelles), ranging from single-celled to complex multicellular organisms, with distinct nutritional and structural differences

Tropical Rainforest

Summer Temp: Stable and warm, usually 20°C to 34°C

• Precipitation: Very high; 2,000–10,000 mm annually.

• Biodiversity: Highest on Earth; home to over 50% of all species.

Desert

Summer Temp: Very hot, averaging 29°C to 35°C (can peak much higher).

• Precipitation: Very low; less than 250 mm annually.

• Biodiversity: Low; limited to highly specialized, drought-resistant species.

Boreal Forest (Taiga)

Summer Temp: Mild to warm, ranging from 10°C to 21°C

• Precipitation: Moderate; 300–850 mm (mostly snow in winter).

• Biodiversity: Low-Moderate; dominated by coniferous trees and hardy mammals.

Tundra

Summer Temp: Cold and brief, between 3°C and 12°C

• Precipitation: Very low; 150–250 mm (often called a "cold desert").

• Biodiversity: Lowest; restricted by permafrost and a very short growing season.