Evolution Flashcards

Question

what is an endangered species?

Answer 1

a species that is in danger of becoming extinct

Answer 2

A characteristic of an organism which increases its likelihood of survival in its environment

Answer 3

natural selection

Answer 4

structural, behavioural and physiological

Answer 5

Anatomical or morphological features of an organism. Body coverings (fur, bright feathers, spines…) Limb specialisations (webbed feet, opposable thumbs, wings, flippers…) Sensory organs (eyes, ears….)

Answer 6

The things that an organism does which help them survive and thrive. Communication Social/territorial interactions (including conflict and cooperation) Mating behaviours Obtaining food Maintaining homeostasis

Answer 7

The way an organism responds on a cellular and molecular level. Regulating body temperature Water balance Nutrient balance Reproductive strategies Senses and processing of sensory information

Answer 8

food/water/air shelter/space/freedom from predators access to mates (in order to pass on their genes)

Answer 9

the very slow very gradual changes in the POPULATION (not individual) over many generations that means that the individual animals and therefore the population can thrive in the place where they live

Answer 10

First proposed by Charles Darwin in ‘On the Origin of Species’ in 1859. The main mechanism for evolutionary change. Proposes that organisms that are well adapted to their environment will more likely survive and thrive (produce more offspring) and pass on their genes, whereas those who are not adapted will die off. This process causes species to change and diverge over time.

Answer 11

Selection pressures are external agents which affect an organism's ability to survive in a given environment. They can be biotic (living) or abiotic (non-living)

Answer 12

Resources - Food availability (biotic), Shelter (abiotic), Availability of mates (biotic) Physical environment - Temperature (abiotic), Weather (abiotic), Geography (abiotic) Biological factors - Predators (biotic), Diseases (biotic)

Answer 13

1. Variation exists in populations of organisms, requires differences to exist in the characteristics of individuals in a population. Differences largely arise through random mutations in genes. 2. Specific animals have traits that make them well adapted to their environment (or more successful at meeting their three categories of needs). Some variations help organisms survive (they are selected for/have a selective advantage). Organisms with less favourable characteristics die out (selected against). 3. Survival of the fittest - those that have the traits to make them more successful are more likely to survive, reproduce and increase those traits in the gene pool of the next generation. There is a struggle for survival referred to as ‘selective pressures’. Not all individuals in the population can survive. 4. Over a LONG, LONG time the gene pool of the population will change, resulting in greater adaptation and the evolution of species. The organisms that survive pass on their traits to the following generations and over time the population changes to become better adapted to its environment.

Answer 14

If the environment changes (e.g. a new predator arrives, climate change...), or if a population migrates to a new environment, then different characteristics may be selected for – and the population will evolve in a different direction.

Answer 15

Most evolutionary change is slow and gradual. Complex structures, like eyes and wings, evolved through small changes over many generations. Existing structures were built upon over generations. Each stage provided a survival advantage to that species.

Answer 16

Also known as selective breeding. Artificial selection involves humans selecting individuals (plants or animals) that have the most desirable phenotypes, and exclusively breeding these individuals. Over several generations, this process will change the population to become more suited to human needs/desires.

Answer 17

Artificial selection - humans select individuals with the most desirable phenotypes Natural selection - nature selects individuals with the fittest phenotypes

Answer 18

- Reduces genetic diversity - increasing susceptibility to disease - Often contradicts natural selection - creating individuals with health issues and unsuitable traits

Answer 19

- Artificial selection is certainly beneficial for humans who want plants and animals to show particular traits (such as better quality meat, wool, more aesthetic)

Answer 20

All organisms can be uniquely identified using levels of classification. As you move down the levels - each grouping contains fewer organisms, but the organisms become more similar and more closely related.

Answer 21

Members of the same species are able to interbreed to produce viable and fertile offspring. If the offspring of two organisms are not fertile (able to reproduce), then they are considered to be different species

Answer 22

Some species exhibit considerable variation across their range, and therefore groups in different regions are further classified as subspecies. (in time they may become separate species)

Answer 23

Speciation is the process where over time populations that are separated and experience different selective pressures, evolve (over many, many generations) to the point that they are no longer able to produce fertile offspring. The process by which new species are formed from an original ancestral species.

Answer 24

the inability of a species to breed successfully with related species due to geographical, behavioural, physiological, or genetic barriers or differences

Answer 25

able to survive and reproduce

Answer 26

able to reproduce

Answer 27

1. variation exist in the population/species 2. Original population/species become geographically isolated into populations, cutting off migration between populations Physical barriers: River, Mountains, Continental drift, Rising sea levels, Climate change 3. Different selection pressures act on the populations and favour those individuals with traits suited to each environment. 4. Over a long period of time reproductive isolation occurs - even if the barriers are removed, individuals from different groups are unable to interbreed to produce viable/fertile offspring. They have become different species.

Answer 28

The evolution of life on this planet has already occurred. Therefore it cannot be directly observed. Various forms of evidence can be used to conclude that all life is related and evolved from a common ancestor.

Answer 29

Fossilisaton provides a record of how creatures evolved and how this process can be represented by a 'tree of life', showing that all species are related to each other.

Answer 30

Palaeontology Comparative anatomy Comparative embryology Molecular biology Biogeography

Answer 31

The study of fossils. Include: direct evidence, such as fossilised bones, teeth and shells, indirect evidence, traces of fossils such as footprints Provide evidence of the pre-existing life forms that lived on Earth. However the fossil record is largely incomplete.

Answer 32

Fossils which are an intermediate between an ancestral species and a descendent species. Help to establish an evolutionary relationship between species which appear very different to each other.

Answer 33

The process of a fossil forming. Most commonly occurs when: The organism is rapidly covered by oxygen poor sediment, meaning it is hidden from scavengers and decomposition is slowed. Over a long period of time the sediment surrounding the fossil forms into sedimentary rock.

Answer 34

Determining the order of age of fossils (without finding their precise age). Stratigraphy, studying rock layers, allows us to determine the relative age of fossils Deeper layers = older fossils

Answer 35

Provides a precise estimate of a fossil’s age. Radioisotopes, such as carbon-14 (carbon dating) can be measured in a fossil sample. The relative amount of these isotopes in the fossils is used to determine its age. if we measure the speed of breakdown of the isotope (called radioactive decay), we can work out how long an organism has been dead

Answer 36

Similarity in the structural features of organisms provides evidence of their evolutionary relationship

Answer 37

Structures that serve the same function in different organisms, but have evolved independently, eg; Wings in birds, insects, bats, pterosaurs Fins in fish and flipper in whales/dolphins

Answer 38

Structures in different species which are similar due to being inherited from a recent common ancestor. Eg; although different mammalian species have highly modified forelimbs there are similarities in the bone structure. These similarities suggest a common evolutionary ancestor for all mammals.

Answer 39

Structures that no longer perform the same function as in other organisms. These organs must have been important in some ancestral form, but became redundant in later species.

Answer 40

Similarities in the developing embryos of different species. Suggests a common evolutionary ancestor.

Answer 41

The study of the geographical distribution of organisms.

Answer 42

Comparing the similarities in the molecules that make up organisms. Eg; Genes (sequences of DNA bases) Proteins (sequences of amino acids) Haemoglobin Cytochrome C The more similar the molecules of two different species, the more closely related they are.

Answer 43

DNA hybridisation is a technique to compare the DNA sequences of two species to find out how closely they are related.

Answer 44

a large difference in amino acid sequences between two organisms means they had a distant common ancestor, while a small difference in amino acid sequences mean they had a recent common ancestor

Answer 45

A visualisation of the relatedness of different species. Each branch point represents a shared ancestor between groups of species.

Answer 46

refers to any parts of, or impressions made by, a plant or animal that survives following death

Answer 47

Rather than evolving from chimpanzees, they are our closest living relatives We share a common ancestor with the apes Gorillas diverged from this common ancestor earlier than chimpanzees and bonobos did

Answer 48

- Bipedalism (ability to walk on two legs) - Large and complex brain

Answer 49

- Energy-efficient form of movement - Helps avoid predators (standing taller enables you to see further), better gathering - Frees up the hands - Keeps the body cool with less direct surface area exposed to the sun and greater air flow in drier air to increase sweat evaporation.

Answer 50

- Enables us to store more information - Enables us to collect and process information - Enables us to solve problems BUT - It is energy inefficient, and means we need larger skulls - Makes for difficult births

Answer 51

* Spinal cord enters human skull (through foramen magnum) from beneath * This means less energy is needed to balance the the head * Ape skulls attach from behind.

Answer 52

Warm blooded vertebrates, Give birth to live young

Answer 53

Opposable thumb, Flattened nails (not claws), 3D colour vision, Relatively large brains

Answer 54

No tail (unlike monkeys), Posture is partially or fully erect allowing hands to manipulate food, care for young or use tools, Larger body size and brain

Answer 55

Centering of hole in base of skull: Head is above centre of gravity - maintain balance Reduction in relative arm length: Closer to centre of gravity Femur: Longer and angled inwards from the hips. Positions upper body over the centre of gravity. Shape of Foot: Platform shape (loss of opposable big toe)

Answer 56

- Carrying offspring. - Carrying food away from a kill site or growing site to a position of safety. - Efficient Locomotion: Bipedalism provides an energy efficient method that favours low speed, long distance movement – walking. - Seeing over the grass may have helped to spot predators at a distance. - Holding tools and weapons

Answer 57

- Parasite control - Retention of head hair: Hair on the head reflects solar radiation (heat) before it reaches the skin. - Thermoregulation: Well developed sweat glands allow us to lose heat more efficiently.

Answer 58

Increasing height/body size Increasing brain size and change in skull shape/structure to suit

Answer 59

- Increased cranial capacity (brain size) - Results in an increased cognitive capacity, and therefore problem solving skills and cultural behaviours. - Reduction in brow ridge - Facial angle sloped to vertical - Reduction in jaw size (skull becomes less about processing food, more about big brain storage) - Centring of hole in base of skull (assists bipedalism)

Evolution Flashcards

(83 cards)