Unit 2.1 Species and populations

Question 1

Species

Answer 1

A group of organisms sharing common characteristics and capable of interbreeding to produce fertile offspring.

Examples include the Siberian tiger (Panthera tigris) and the Bald eagle (Haliaeetus leucocephalus).

Question 2

Population

Answer 2

A group of organisms of the same species living in the same area at the same time, capable of interbreeding.

Examples include the population of African wild dogs (Lycaon pictus) in a savanna ecosystem.

Question 3

Habitat

Answer 3

The environment in which a species normally lives.

Examples include coral reefs for marine species and forests for terrestrial species like the redwood (Sequoia sempervirens).

Question 4

Abiotic factors

Answer 4

Non-living physical factors influencing organisms and ecosystems, e.g., temperature, sunlight, pH, salinity, pollutants.

Question 5

Biotic factor

Answer 5

Living components of an ecosystem and their relationships.

Question 6

Niche

Answer 6

The set of abiotic and biotic conditions and resources to which an organism or population responds.

Question 7

Fundamental Niche

Answer 7

Full range of conditions and resources in which a species could survive and reproduce.

Question 8

Realised Niche

Answer 8

Actual conditions and resources in which a species exists due to biotic interactions.

Question 9

What are the types of population interactions

Answer 9

Here are examples with specific animals for each type of interaction:

1. Competition
2. Predation
3. Herbivory
4. Parasitism
5. Mutualism

Question 10

Example of Mutualism

Answer 10

Clownfish and anemones

clownfish gets protection from predators by living among the anemone’s tentacles, and in return, it helps lure fish into the anemone and provides nutrients through its waste.

Question 11

Example of Competition

Answer 11

In the Galápagos Islands, marine iguanas and sea lions compete for basking spots on the rocks to warm up after foraging in the cold water

Question 12

Example of Predation

Answer 12

The Arctic fox preys on lemmings, changing its hunting strategy based on the lemming population size and the season.

Question 13

Example of Herbivory

Answer 13

Koalas feed exclusively on eucalyptus leaves, which are tough and have low nutritional value, but koalas have specialized digestive systems to cope with this diet.

Question 14

Example of Parasitisim

Answer 14

Mosquitoes feeding on human blood. This interaction is necessary for female mosquitoes to develop their eggs. Unfortunately, during this process, mosquitoes can transmit various pathogens (viruses, parasites, and bacteria) to humans, causing diseases such as malaria, denge fever, yellow fever…

Question 15

Sigmoid growth pattern

Answer 15

S-curves depict logistic growth, showing how a population grows rapidly but stabilizes as it reaches carrying capacity.

Question 16

Exponential growth pattern

Answer 16

J-curves represent exponential population growth without environmental limitations

Question 17

Carrying Capacity

Answer 17

Carrying capacity is the maximum population size that the environment can sustain indefinitely, given the food, habitat, water, and other necessities available in the environment.

Question 18

Limiting factors

Answer 18

1. Density-dependent factors: factors that lower birth rates as a population grows in size

Preditation
Availability of resources
Nutrient supply
Disease
Accumulation of waste

2. Density-independent factors: factors that affect a population irrespective of population density

Phenomena
Abiotic factors
Weather conditions

PANDA PAW