10 adaptations and diversity

Question 1

explain how genetic diversity allows populations to survive in a changing environment

Answer 1

• Increases the number of individuals that can survive and reproduce
• Increases biodiversity in ecosystems
• Allows natural selection to act, as there are many alleles to select from

Question 2

describe three factors that can affect the gene pool of the population

Answer 2

Mutation (random change in the DNA of a gene):

• can form new allele
• can be passed on to offspring if in reproductive cells

Recombination forms new combinations of alleles:

• usually occurs during meiosis: crossing over and independent assortment

Gene immigration (gene flow): transfer of genetic material from one population to another by migration of individuals or gametes.

• can alter genetic diversity by changing the frequencies of alleles in populations

Question 3

explain how humans can use technology to allow us to survive outside our normal tolerance range

Answer 3

Biomimicry: science that looks at nature for inspiration and comes up with ideas for solving problems. Humans use biomimicry to survive outside our normal tolerance range by learning from the designs and adaptations in nature.

Question 4

define and provide three examples of physiological adaptations

Answer 4

Physiological adaptation: internal body processes and chemicals involved

• Camel humps store fat and use it as nourishment when food is scarce
• Female black widow spiders produce toxins and venom to catch prey
• Plants produce thick and waxy skin to help prevent water loss

Question 5

define and provide three examples of behavioural adaptations

Answer 5

Behavioural adaptation: actions of the organism

• Desert lizards dig underground burrows or holes to escape the heat
• Fennec foxes are active at night to avoid the high temperatures during the day
• Scorpions bury themselves in the sand to avoid heat and also catch prey

Question 6

define and provide three examples of structural adaptations

Answer 6

Structural adaptation: physical features of the organism

• Spines on cactus allows protection from animals and provides shade which limits water loss
• Camels have large and flat feet which makes it more efficient to travel on sand
• Large ears of jackrabbits allow them to cool down their body temperature

Question 7

explain the adaptations desert animals have to survive low water availability

Answer 7

Behavioural adaptation: Being nocturnal means they’re active during the cooler nighttime hours and rest during the scorching daytime. This helps them avoid losing water through excessive sweating.
Physiological adaptation: Many desert animals have concentrated urine, which means they produce less urine so they don’t lose as much water.
Structural adaptation: Some lizards have scales that absorb water through their skin.

Question 8

explain the adaptations desert plants have for survival and reproduction

Answer 8

Decreasing heat uptake:

• Lightly coloured and reflective leaves (or photosynthetic organs)
• Producing leaves with small surface areas
• Orienting leaves vertically to minimise surface area

Increasing water uptake:

• Maximising water uptake (deep roots, horizontal roots, many small roots)
• Plants store water to save for use in the dry season (large water reserves in hollow trunks, cacti cells in stems or underground)

Minimising water loss:

• Thick, waxy cuticle
• Reduced number of stomata
• Leaf shape and orientation
• Sunken stomata and stomatal hairs
• Rolled up leaves

Question 9

explain the adaptations aquatic animals have for survival in very cold conditions

Question 10

explain how plants survive in freezing conditions

Question 11

define ecosystem

Answer 11

multiple communities interacting with one another and their physical environment. Ecosystems are made up of both biotic and abiotic factors

Question 12

define community

Answer 12

populations of organisms living together in the same habitat

Question 13

define population

Answer 13

group of organisms of the same species in the same area

Question 14

explain how energy is gained and transferred within ecosystems

Answer 14

producers > consumers > decomposers

Question 15

state the features that allow organisms to be classified as producers, consumers or decomposers

Answer 15

Producers/Autotrophs:

• Captures sunlight energy and converts it into useable chemical energy
• Organic compounds made by producers provide chemical energy that supports their own needs & other members of a community indirectly or directly

Consumers:

• Heterotrophs that obtain their energy by absorbing or digesting other organisms or parts of them
• Rely directly or indirectly on the chemical energy of producers

Decomposers:

• Typically fungi and bacteria
• Heterotrophs obtain energy and nutrients from organic matter & their food is dead organic material
• Breaks down dead organisms and wastes from consumers which are converted back into simple mineral nutrients that return back to the environment

Question 16

define and give an example of a keystone species

Answer 16

Keystone species: organisms that have a large impact on the ecosystem in which they live

• e.g. Sea otters, beavers

Question 17

explain the consequences of the removal of keystone species

Answer 17

Loss of Biodiversity: keystone species often regulate the populations of other species in their ecosystem. When they’re removed, the population sizes of other species can experience dramatic changes, leading to a decline in biodiversity as some species may become overabundant, while others may decline or disappear entirely.

Disruption of Food Chains: keystone species may be top predators, controlling the population sizes of their prey species. When they’re removed, the prey species can become overpopulated leading to a cascade of effects throughout the food chain.

Altered Habitat Structure: keystone species shape and modify their environment. When they’re removed, the habitat structure can change, affecting the resources available to other organisms.

Loss of Ecosystem Services: Keystone species provide essential ecosystem services that benefit the environment and humans. For example, some keystone species, like bees, play a crucial role in pollination, which is necessary for the reproduction of many plants. When a keystone species is lost, the ecosystem services it provides can be significantly diminished.

Question 18

state the factors that affect population size

Answer 18

• births
• deaths
• immigration
• emigration

Question 19

compare density-dependant and density-independent factors

Answer 19

Density-dependent: factors that change based on how many individuals are in a population

• Competition
• Disease and parasitism
• Predation

Density-independent: factors that affect a population regardless of how many individuals there are

• Natural disasters
• Climate
• Human activities

Question 20

define and explain why can’t populations maintain a J-curve

Answer 20

J-curve: graph that shows how a population grows over time. It starts with a small population and then increases rapidly

• Populations can maintain a J-curve when there are enough resources available, limited factors controlling the population size, and a higher reproduction rate than death rate. However, this growth pattern is not sustainable in the long term, as limitations and carrying capacity come into play.

Question 21

define carrying capacity and draw a graph of its shape

Answer 21

Carrying capacity: maximum number of individuals of a species that an environment can support

• S shape

Question 22

compare K- and r-selection using specific examples - include the conditions in which each will be more successful

Answer 22

K-selection: strategy that focuses on producing few offspring but gives them a lot of care to increase their chances of survival e.g. Humans

• successful in stable environments where resources are limited, competition is high, and there is enough time and resources to invest in raising and nurturing offspring

r-selection: strategy that focuses on producing many offspring quickly without providing a lot of care for each individual e.g. Insects

• successful in unpredictable environments where resources are abundant and competition is lower

Question 23

describe techniques that the Aboriginal and Torres Strait islander used to modify the environment

Answer 23

Cool-burning: Aboriginal peoples used controlled fires to manage the landscapes.

• Burn specific areas at certain times of the year to encourage the growth of different plants and grasses
• Help with hunting, improved the quality of pastures for animals, and reduced the risk of larger, uncontrolled bushfires.

Question 24

describe how observations by Aboriginal and Torres Strait islanders allowed them to survive (resources and tools)

Question 25

interactions between ecosystems

Answer 25

Commensalism: one member gains the benefit and the other member neither suffers harm nor gains apparent benefit

• e.g. Whale and barnacle

Mutualism: two different species in which both gain some benefit

• e.g. Sea anemone and clownfish

Parasitism: one kind of organism (the parasite) lives on or in another kind (the host) and feeds on it

• e.g. Dog and tick