4.1 - Species, communities and ecosystems

Question 1

Define species

Answer 1

Groups of organisms that have the potential to produce fertile offspring

Question 2

What is the difference between interbreeding and crossbreeding?

Answer 2

Interbreeding: two members of the same species mating and producing fertile offspring

Crossbreeding: two members of different species mating to produce infertile offspring

Question 3

Define population

Answer 3

Population: a group of the same species in the same area at the same time.

Question 4

Define community

Answer 4

Community: all the populations of different species living and interacting together in an area at the same time.

They are interdependent and cannot survive alone. Typically there will be hundreds to thousands of species in one community.

Question 5

Define ecosystem

Answer 5

Ecosystem: a highly complex system involving interactions within a community as well as the community’s interactions with the abiotic environment (the place where the community lives).

Question 6

Define nutrition

Answer 6

A supply of organic nutrients required for growth and reproduction

Question 7

Define nutrient

Answer 7

An element an organism needs to survive

Question 8

Name the methods of nutrition with named examples

Answer 8

Autotrophic: self-feeding, makes its own organic compounds from pre-existing simple inorganic substances. e.g. Arabidopsis thaliana

Heterotrophic: feeding on others, obtains carbon compounds from others e.g. hummingbirds

Mixotrophic: both auto- and heterotrophic. e.g. Euglena gracilis

Question 9

What are the types of heterotroph?

Answer 9

Consumer: ingest other organisms - take in undigested material, internally digest it, absorb products. Ranked primary, secondary, tertiary. e.g. human

Detritivore: obtain nutrients from dead organic matter (detritus) - ingest then internally digest e.g. earthworm

Saprotroph: obtain nutrients from dead organix matter - secrete digestive enzymes into detritus, externally digest then absorb e.g. fungi

Question 10

What are the 5 elements required to sustain life?

Answer 10

C H O N P

Can make most carbon compounds required to sustain life. About 15 other elements present as traces

Question 11

What is a nutrient cycle? What is its function?

Answer 11

Nutrient cycle: cycle of inorganic nutrients between reserves in abiotic environment and element forming part of living organism

Purpose: maintain inorganic nutrient supply

Question 12

Define sustainable

Answer 12

Sustainable: able to continue indefinitely

Question 13

What things make an ecosystem sustainable?

Answer 13

1) Nutrient availability: recycling of others’ waste as food
2) Detoxification of waste products (a form of recycling waste) e.g. ammonium ions
3) Energy availability: mostly sunlight

Question 14

What is a mesocosm?

Answer 14

A mini ecological experiment - kind of like a little controlled section of an ecosystem